阅读说明：本技术 使用衍射光学元件的激光发生器 (Laser generator using diffractive optical element ) 是由 K·格拉斯 于 2018-07-13 设计创作，主要内容包括：本公开总体涉及用于激光发生器的设备、方法和系统,并且更具体涉及具有光学组件的激光发生器,其允许光纤导管耦合到激光发生器,同时递送激光射束。(The present disclosure relates generally to apparatus, methods, and systems for a laser generator, and more particularly to a laser generator having an optical assembly that allows a fiber optic conduit to be coupled to the laser generator while delivering a laser beam.)

1. A laser generator comprising:

a laser source that generates a beam of light; and

an optical assembly downstream of the laser source, wherein the optical assembly receives the light beam, wherein the optical assembly comprises:

a wave plate receiving the light beam;

a thin film polarizer downstream of the wave plate and receiving the optical beam and reflecting a first portion of the beam and allowing a second portion of the beam to pass through the thin film polarizer;

a beam stop receiving the first portion of the beam;

a beam expander downstream of the wave plate and receiving the second portion of the beam;

a diffuser downstream of the beam expander and receiving the second portion of the light beam; and

a hybrid fiber downstream of the diffuser and receiving the second portion of the light beam, wherein the hybrid fiber emits the second portion of the light beam.

2. The laser generator of claim 1, wherein the laser source generates a light beam comprising approximately 355 nanometers.

3. The laser generator of claim 1, wherein the laser source generates a light beam between about 10 nanometers and about 5000 nanometers.

4. The laser generator of claim 1, wherein the diffuser is a diffractive optical element.

5. A laser generator comprising:

a laser source that generates a light beam having a plurality of pulses, wherein the pulses comprise a pulse width; and

an optical assembly downstream of the laser source, wherein the optical assembly receives the light beam, wherein the optical assembly comprises:

a wave plate receiving the light beam;

a thin film polarizer downstream of the wave plate and receiving the optical beam and reflecting a first portion of the beam and allowing a second portion of the beam to pass through the thin film polarizer, wherein the second portion of the beam has the pulse width;

a beam stop receiving the first portion of the beam;

means for stretching the pulse width of at least one pulse of the plurality of pulses in the second portion of the beam; and

a diffuser downstream of the means for stretching the pulse width and receiving and transmitting another portion of the second beam.

6. The laser generator of claim 5, wherein the means for stretching the width of at least one of the plurality of pulses comprises a beam splitter and a plurality of mirrors that create a beam path.

7. The laser generator of claim 6, wherein at least one of the mirrors is translatable.

8. The laser generator of claim 5, wherein the means for stretching the width of at least one pulse of the plurality of pulses comprises a beam splitter.

9. The laser generator of claim 8, wherein the beam splitter splits the second portion of the beam into a first beam and a second beam.

10. The laser generator of claim 9, wherein the beam combines the second beam with the first beam after the second beam has passed through a time delay loop.

11. The laser generator of claim 10, wherein the time delay loop comprises a plurality of mirrors.

12. The laser generator of claim 10, wherein the time delay loop comprises a hybrid fiber.

13. The laser generator of claim 12, wherein the hybrid fiber is a coherent hybrid fiber.

14. A method of using the laser generator of claim 5, wherein the method comprises coupling the laser generator to a catheter having a plurality of optical fibers and inserting the catheter into a vessel of a patient and removing at least a portion of an obstruction with respect to the vessel of the patient.

Technical Field

The present disclosure relates generally to apparatus, methods, and systems for a laser generator, and more particularly to a laser generator having an optical assembly that allows a fiber optic conduit to be coupled to the laser generator while delivering a laser beam.

Background

When performing a laser atherectomy procedure in a patient's vasculature and utilizing a disposable fiber optic catheter, the catheter is typically coupled to a laser generator, such as CVX-300 manufactured by Spectranetics Corporation, Colorado Springs, CO, USA^TMAn excimer laser system. Different laser generators typically produce different laser beams. CVX-300^TMExcimer laser systems produce a 308 nanometer laser beam with a pulse width of approximately 135 nanoseconds (nsec). Other laser systems may produce laser beams having different wavelengths and pulse widths. For example, a Nd: YAG laser operating at its third harmonic produces a 355nm laser beam with a pulse width of approximately 8 nsec. A 308 nanometer laser beam having a pulse width of approximately 135nsec may be capable of producing a maximum energy output of 140 millijoules (mJ), and a 355 nanometer laser beam having a pulse width of approximately 8nsec may be capable of producing a maximum energy output of 200 millijoules (mJ). But if the energy in the pulse exceeds a certain threshold, the optical fiber in the laser catheter used to deliver the energy is potentially subject to failure. The likelihood of such a failure increases if the laser beam inherently has a large peak power. For example, due to the relatively short duration of the pulse width of the 355nm laser beam (e.g., 8nsec) compared to the 308nm laser beam having a pulse width of 135nsec, the 355nm laser beam must have a substantially higher peak power for a given pulse because the pulse width of the 355nm beam is more than sixteen times shorter than the length of the pulse width of the 308nm beam. Therefore, it is desirable to increase the pulse width of the laser beam in order to reduce the peak power of the energy passing through the fiber to reduce the peak power of the energyThe power level is prevented from exceeding the damage threshold of the fiber delivery device. Furthermore, regardless of the wavelength of the laser beam, it may be desirable to improve the symmetry and uniformity of the intensity of the laser beam exiting the laser system and/or disposable fiber optic catheter in order to further reduce the likelihood of damaging the optical fiber.

Disclosure of Invention

The devices of the present disclosure increase the pulse width of the laser beam and reduce the peak power through the optical fiber, thereby minimizing and/or preventing the power level from exceeding the damage threshold of the fiber delivery device. Furthermore, the apparatus of the present disclosure improves the symmetry and uniformity of the intensity of the laser beam exiting the laser system and/or disposable fiber optic catheter to further reduce the likelihood of damaging the optical fiber.

An apparatus for performing intravascular ablation comprising a laser generator including a laser source producing a light beam and an optical assembly downstream of the laser source, wherein the optical assembly receives the light beam, wherein the optical assembly comprises: a wave plate (waveplate) receiving the light beam; a thin film polarizer downstream of the wave plate and receiving the optical beam and reflecting a first portion of the beam and allowing a second portion of the beam to pass through the thin film polarizer; a beam stop (dump) receiving a first portion of the beam; a beam expander downstream from the wave plate and receiving a second portion of the beam; a diffuser downstream of the beam expander and receiving a second portion of the light beam; and a hybrid fiber downstream of the diffuser and receiving a second portion of the light beam, wherein the hybrid fiber emits the second portion of the light beam.

The laser generator of the preceding paragraph, wherein the laser source generates a light beam comprising approximately 355 nanometers.

The laser generator of any of the preceding paragraphs, wherein the laser source generates a light beam between about 10 nanometers and about 5000 nanometers.

The laser generator of any of the preceding paragraphs, wherein the diffuser is a diffractive optical element.

Another apparatus for performing intravascular ablation, comprising a laser generator comprising: a laser source that generates a light beam having a plurality of pulses, wherein the pulses comprise a pulse width; and an optical assembly downstream of the laser source, wherein the optical assembly receives the light beam, wherein the optical assembly comprises: a wave plate receiving the light beam; a thin film polarizer downstream of the wave plate and receiving the optical beam and reflecting a first portion of the beam and allowing a second portion of the beam to pass through the thin film polarizer, wherein the second portion of the beam has the pulse width; a beam stop receiving a first portion of the beam; means for stretching a pulse width of at least one pulse of a plurality of pulses in a second portion of the beam; and a diffuser downstream of the means for stretching the pulse width and receiving and transmitting another portion of the second beam.

The laser generator of the preceding paragraph, wherein the means for stretching the width of at least one of the plurality of pulses comprises a beam splitter and a plurality of mirrors that create the beam path.

The laser generator of any of the preceding paragraphs, wherein at least one of the mirrors is translatable.

The laser generator of any of the preceding paragraphs, wherein the means for stretching the width of at least one of the plurality of pulses comprises a beam splitter.

The laser generator of any of the preceding paragraphs, wherein the beam splitter splits the second portion of the beam into a first beam and a second beam.

The laser generator of any of the preceding paragraphs, wherein the beam combines the second beam with the first beam after the second beam has passed through a time delay loop.

The laser generator according to any of the preceding paragraphs, wherein the time delay loop comprises a plurality of mirrors.

The laser generator of any of the preceding paragraphs, wherein the time delay loop comprises a hybrid fiber.

The laser generator of any of the preceding paragraphs, wherein the hybrid fiber is a coherence hybrid fiber.

The present disclosure also includes a method of using a laser generator according to any of the preceding paragraphs, wherein the method includes coupling the laser generator to a catheter having a plurality of optical fibers and inserting the catheter into a vessel of a patient and removing at least a portion of an obstruction with respect to a blood vessel of the patient.

The phrases "at least one," "one or more," and/or "are open-ended expressions that both connect and disconnect in operation. For example, each of the expressions "at least one of A, B and C", "at least one of A, B or C", "one or more of A, B and C", "one or more of A, B or C", "A, B and/or C" means a alone, B alone, C, A and B together alone, a and C together, B and C together, or A, B and C together. When each of A, B and C in the above expressions refers to an element (such as X, Y and Z) or a class of elements (such as X1-Xn, Y1-Ym, and Z1-Zo), the phrase is intended to refer to a single element selected from X, Y and Z, a combination of elements selected from the same class (e.g., X1 and X2), and a combination of elements selected from two or more classes (e.g., Y1 and Zo).

The terms "a" or "an" entity refer to one or more of that entity. As such, the terms "a" (or "an"), one or more, and "at least one" may be used interchangeably herein. It should also be noted that the terms "comprising," "including," and "having" may be used interchangeably.

The term "unit" as used herein shall be given its broadest possible interpretation in terms of 35 u.s.c.section 112 (f). Accordingly, the claims including the term "unit" are intended to cover all structures, materials, or acts set forth herein as well as all equivalents thereof. Further, the described structures, materials, or acts, as well as equivalents thereof, are intended to include all structures, materials, or acts described in this summary of the invention, the description of the drawings, the detailed description of the invention, the abstract, and the claims themselves, as well as equivalents thereof.

The following documents are incorporated herein by reference: (1) U.S. patent nos. 5315614; (2) U.S. patent nos. 7050692; and (3) U.S. patent No. 8059274; (4) references listed on the last page of Exhibit 1, including but not limited to: (a) tianheng Wang, Patrick D.Kumavor and Quing Zhu, Application of laser pulsing scheme for influencing laser energy in photoacousticing, Journal of Biomedical Optics 17(6), 061218-1 to 061218-8 (6 months 2012); (b) rajeev Khare and Paritosh K.Shukla, Ch.10-Temporal striking of Laser lasers, Coherence and Ultrashort Pulse Laser Emission (11 months 2010); and (c) air Herzog, driver Malka, Zeev Zalevsky and AmielA. Ishaya, Effect of spatial coherence on damage occurence in multimodiopical fibers, p.415, p.2015, 1/40, and 3/OptiCS LETTERS.

It should be understood that each maximum numerical limitation given throughout this disclosure is considered to include every lower numerical limitation as an alternative, as if such lower numerical limitations were expressly written herein. Each minimum numerical limitation given throughout this disclosure is considered to include each higher numerical limitation as an alternative, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this disclosure is considered to include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

The foregoing is a simplified summary of the disclosure to provide an understanding of some aspects of the disclosure. This summary is neither an extensive nor exhaustive overview of the disclosure and its various aspects, embodiments, and configurations. This summary is intended to neither identify key or critical elements of the disclosure nor delineate the scope of the disclosure, but rather to present selected concepts of the disclosure in a simplified form as an introduction to the more detailed description presented below. As will be appreciated, other aspects, embodiments and configurations of the present disclosure are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below.

Drawings

The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application with color drawing(s) will be provided by the office upon request and payment of the necessary fee.

The accompanying drawings are incorporated in and form a part of the specification to illustrate several examples of the present disclosure. Together with the description, these drawings explain the principles of the disclosure. The drawings simply illustrate possible and alternative examples of how the disclosure may be made and used and are not to be construed as limiting the disclosure to only those examples illustrated and described. Further features and advantages will become apparent from the following more detailed description of the various aspects, embodiments and configurations of the disclosure as illustrated by the drawings referenced below.

Fig. 1 illustrates an exemplary ablation system including a laser generator and a laser catheter of the present disclosure.

Fig. 2A is a perspective view of a laser catheter or fiber optic catheter of the present disclosure.

Fig. 2B is a cross-sectional view of an optical fiber of a rectangular fiber coupler.

Fig. 3 is a perspective view of a distal portion of a laser catheter or fiber optic catheter of the present disclosure.

Fig. 4 is an end view of the distal end of a laser catheter or fiber optic catheter of the present disclosure.

Fig. 5 is a schematic view of an ablation system of the present disclosure.

Fig. 6 is a schematic view of an alternative ablation system of the present disclosure.

Fig. 7A is a graphical representation of an energy signal emitted from the ablation system depicted in fig. 6, wherein the energy signal is approximately 40 percent of the energy initially entering the beam splitter.

Fig. 7B is a graphical representation of an energy signal emitted from the ablation system depicted in fig. 6, wherein the energy signal is a resulting signal formed by combining and overlapping approximately 40 percent of the energy initially entering the beam splitter with the remaining energy traversing the time delay loop.

Fig. 8A is a color plot depicting the energy density of a laser beam emitted from the ablation system depicted in fig. 6 using a circular optical assembly.

Fig. 8B is a color plot depicting the energy density of a laser beam emitted from the ablation system depicted in fig. 6 using a rectangular optical assembly.

Fig. 9 is a comparison of ablation rate emitted from a 355nm laser system similar to or the same as the laser system illustrated in fig. 6 including a beam stretching technique versus a 308nm laser system without a beam stretching technique.

FIG. 10A is an image of a hole ablated in the pig aorta with a single 600 micron fiber using a 355nm laser system similar to or the same as the laser system illustrated in FIG. 6, with the fiber outputting about 60mJ/mm at 20Hz, and applying a downward force of about 5g²。

FIG. 10B is an image of a hole ablated in the pig aorta with a single 600 micron fiber applying a downward force of about 5g and using a 308nm laser system, where the fiber outputs about 60mJ/mm at 20Hz²。

FIG. 11A is an image of a histological cross-section of a hole ablated in the porcine aorta with a single 600 micron fiber applying a downward force of about 5g and using a 355nm laser system similar or identical to the laser system illustrated in FIG. 6, wherein the fiber outputs about 60mJ/mm at 20Hz²。

FIG. 11B is an image of a histological cross-section of a hole ablated in the porcine aorta with a single 600 micron fiber applying a downward force of about 5g and using a 308nm laser system, where the fiber outputs about 60mJ/mm at 20Hz²。

Fig. 12 is a schematic view of a further alternative ablation system of the present disclosure.

It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the present disclosure or that provide other details that are difficult to perceive may have been omitted. Of course, it should be understood that this disclosure is not necessarily limited to the particular embodiments illustrated herein.

Detailed Description

Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof is meant to encompass the items listed herein and equivalents thereof as well as additional items.

In the drawings, similar components and/or features may have the same reference numerals. Further, components of the same type may be distinguished by following the reference label by a letter that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label regardless of the second reference label.

Referring to fig. 1, an exemplary ablation system 100 of the present disclosure is depicted. The ablation system 100 includes a laser device 130 coupled to a laser controller 135. Controller 135 includes one or more computing devices programmed to control laser 130. The controller 135 may be internal or external to the laser device 130 (such as a laser generator). The laser device 130 may comprise an excimer laser, a Nd: YAG laser, or another suitable laser. In some embodiments, laser 130 generates light in the ultraviolet frequency range. In one embodiment, the laser 130 generates optical energy in pulses.

The laser 130 is connected to the proximal end of the laser energy delivery system 120, illustratively a laser catheter 150, via a coupler 140. The laser catheter 150 includes one or more transparent members that receive laser energy from the laser 130 and transmit the received laser energy from the first proximal end 160 of the laser energy catheter 150 toward the second distal end 170 of the laser catheter 150. The distal end 170 of the catheter 150 may be inserted into a blood vessel or tissue of the human body 110. In some embodiments, the system 100 employs a plurality of light guides as transmission members, such as optical fibers, that direct laser light from the laser 130 through the catheter 150 toward a target area in the human body 110.

Exemplary laser catheter devices or assemblies may include a laser catheter and/or a laser sheath. An example of a laser catheter or laser sheath is represented by ELCA^TMAnd Turbo Elite^TM(each of which is used for coronary or peripheral interventions, such as re-occluding an artery, altering lesion morphology and facilitating scaffold placement), and SLSIII^TMAnd GlideLight^TM(which is used for surgical implant lead removal) are sold. The working (distal) end of the laser catheter typically has a plurality of laser emitters that emit energy and ablate the target tissue. The opposite (proximal) end of the laser catheter typically has a fiber optic coupler 140 and an optional strain relief member 145. The fiber coupler 140 is connected to the laser system or generator 130. One such example of a laser system is the CVX-300 excimer laser system, which is also sold by spectra corporation.

The laser controller 135 of fig. 1 includes a non-transitory computer-readable medium (e.g., memory) including instructions and/or logic that, when executed, cause one or more processors to control the laser 130 and/or other components of the ablation system 100. The controller 135 includes one or more input devices to receive input from an operator. Exemplary input devices include keys, buttons, touch screens, dials, switches, mice, and trackballs, which provide for user control of laser 130. The controller 135 also includes one or more output devices that provide feedback or information to the operator. Exemplary output devices include displays, lights, audio devices, which provide user feedback or information.

The laser source of laser 130 is operatively coupled to laser controller 135. The laser source is operable to generate a laser signal or beam and provide the laser signal to a human through the fiber optic bundle of the catheter 150. The fiber optic bundle serves as a delivery device for delivering the laser signal to a target region of the human body 110.

Fig. 1 depicts a catheter 150 entering a leg of a human body, preferably through a femoral artery. As discussed above, it may be desirable to treat either Cardiac Artery Disease (CAD) or Peripheral Artery Disease (PAD). After entering the femoral artery, if the catheter 150 is intended to treat CAD, the catheter 150 will be guided through the patient's vasculature and to the coronary arteries. Alternatively, if the catheter 150 is intended to treat PAD, the catheter 150 will be passed through the patient's vasculature catheter and to a peripheral artery, such as a blood vessel below the knee, particularly in the patient's leg and/or foot.

Fig. 2A depicts a non-limiting example of a laser energy delivery system 120 (illustratively a laser catheter 150) via a coupler 140 adapted to be coupled to a laser generator 130. For example, laser catheter 150 includes a proximal end 160 and a distal end 170. Catheter coupler 140 is disposed at catheter proximal end 160. Catheter coupler 140 includes a plurality of optical fibers 205, which may be arranged in one or more sets of optical fibers 205, wherein optical fibers 205 are disposed throughout the length of laser catheter 150, including being disposed within coupler 140 and exposed at distal tip 175 of distal end 170. The laser catheter 150 may also include a T or Y connector 180, wherein the connector 180 has an inlet end 185 for a guidewire 190 to be inserted therein. The laser catheter 150 may also include a lumen extending from the connector 180 to the distal end 170 of the catheter 150 at the distal tip 175, thereby allowing a guidewire 190 to be inserted through the catheter 150.

Referring to FIG. 2B, a cross-sectional view of a bundle of multiple fibers 205 of a rectangular fiber coupler 140 (particularly the proximal end of the coupler 140) is shown. The cross section of the coupler 140 in this figure is depicted as being rectangular, with the rectangular shape having a width (W) and height (H) that match the aspect ratios of the different beams entering the coupler 140. The width (W) and height (H) may be different from those shown in the figure, such as smaller or larger widths and/or smaller or larger heights to match the aspect ratios of the different beams entering the coupler 140. Although the cross-section of the fiber optic bundle is depicted as rectangular, the cross-section of the fiber optic bundle may be square, triangular, circular, or some other shape.

Referring now to fig. 3 and 4, the distal end of a laser catheter 150 for use in an atherectomy procedure according to the present disclosure is shown. The laser catheter 150 may or may not include a lumen 210 (as depicted in fig. 3 and 4). If a lumen 210 is included in the laser catheter 150, the clinician can slide the laser catheter over a guidewire (not shown) through the lumen 210. However, it may be preferable for the laser catheter to have a separate guidewire lumen between the inner band 220 and the outer sheath 215.

As shown, the catheter 150 includes an outer sheath 215 or sheath. The outer jacket 215 includes a flexible component having the ability to resist user-applied forces, such as torque, tension, and compression. The proximal end (not shown) of the laser catheter 150 is attached to a fiber optic coupler (not shown and discussed above). The distal end of the laser catheter 150 includes: a tapered outer band 225 attached to the distal end of the outer jacket 215; a plurality of optical fibers 205 acting as laser emitters; an inner band 220 that creates an aperture that provides access to the inner lumen 210. The energy emitted by the optical fiber 205 cuts, separates, and/or ablates body material within the vasculature of the subject in a pattern that is substantially similar to the pattern of the cross-sectional configuration of the laser emitter 10, scar tissue, plaque buildup, calcium deposits, and other types of undesirable lesions.

In this particular example, the optical fibers 205 are provided in a generally concentric arrangement. When the energy emitted by the optical fiber 205 contacts undesirable bodily materials within the subject's vasculature, it separates and cuts such materials in a generally concentric configuration. Although fig. 3 and 4 illustrate the optical fibers 205 in a generally concentric configuration, those skilled in the art will appreciate that there are many other ways and configurations to arrange multiple laser generators. Thus, fig. 3 and 4 are not intended to represent the only manner in which the distal end of the laser catheter 150 may be configured.

Referring to fig. 5, an ablation system 400 of the present disclosure is shown that includes means for coherence mixing. Coherence mixing is a method for reducing the spatial coherence impairments used in optical fibers that emit light of relatively short pulse widths, such as 355 nm. Examples of lasers 405 that produce relatively short pulse width light include Quantel DRL lasers (Quantel inc. bozeman, MT) having a width of 355 nanometers (nm), a pulse width of 8 nanoseconds (nsec), a repetition rate of 1 to 30 hertz (Hz), and a maximum energy output of 140 millijoules (mJ). Alternative examples of laser 405 include the CVX-300 excimer laser system from spectra, inc, having a pulse width of 308 nanometers (nm), 135 nanoseconds (nsec), a repetition rate of 1 to 80 hertz (Hz), and a maximum energy output of approximately 200 millijoules (mJ).

As discussed above, the optical fiber 205 in the laser catheter 150 used to deliver energy is potentially subject to failure if the amount of energy in the pulse exceeds a certain threshold. The likelihood of such a failure increases if the laser beam inherently has a large peak power. For example, due to the relatively short duration of the pulse width of the 355nm laser beam (e.g., 8nsec) compared to the 308nm laser beam having a pulse width of 135nsec, the 355nm laser beam must have a substantially higher peak power for a given pulse because the pulse width of the 355nm beam is more than sixteen times shorter than the length of the pulse width of the 308nm beam. Therefore, it is desirable to increase the pulse width of the laser beam in order to reduce the peak power of the energy traveling through the optical fiber in order to prevent the power level from exceeding the damage threshold of the fiber delivery device.

With continued reference to fig. 5, laser energy is emitted from the laser 405 and launched into a single fiber 520 (or fiber bundle). For example, as discussed above, the laser may include a wavelength of 355 nm. After exiting laser 405, the laser light may be deflected by mirror 410, which directs the laser light to energy control system 415. Energy control system 415 controls the amount or intensity of energy entering ablation system 400 after the laser exits laser 405. For example, the energy control system 415 may reduce the level of energy. The energy control system 415 may include a waveplate 420 and a thin film polarizer 425. Wave plate 420 is an optical device that changes the polarization state of light passing through it. One type of wave plate is a half-wave plate that shifts the polarization direction of linearly polarized light. The half-wave plate may be mounted in a manual or motorized rotating mount and may be positioned in front of the thin film polarizer 425 with respect to the path of travel of the laser. Thus, the energy control system 415, such as the waveplate 420 and the thin film polarizer 425, reduces the energy level(s) of the light and the output of the delivery fiber and/or conduit 150 during alignment of the components and fiber inputs. The light that passes through the wave plate 420 and is then reflected by the thin film polarizer 425 is directed into a beam stop 430, which is an optical element for absorbing the light beam.

As shown in fig. 5, the thin film polarizer 425 reflects a portion of the light to the beam stop 430 and reflects the remaining portion of the light to the mirror 435. Thus, after the light passes through the energy control system 415, the light beam may be deflected by the mirror 435 and subsequently expanded by the beam expander 440. Beam expander 440 may assist in reducing the energy intensity of the laser light incident on the optics further downstream along the optical path of the system. Reducing the energy intensity of the laser assists in preventing light from exceeding the threshold damage level of the optical component, thereby increasing the useful life of the optical component. For example, the beam expander 440 may expand the size of the light beam by a factor of 2.5 or other increments, such as 1.5, 2.0, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, etc., or any sub-increment therebetween. One type of beam expander 440 may comprise a keplerian telescope, which includes two optical lenses 445, 450.

After exiting the beam expander 440, the light beam then passes through a shutter 455 followed by a diffuser lens assembly 460. The shutter 455 is used to switch (open/close) light entering or not entering the downstream optical system. The diffuser lens assembly 460 may include an engineered diffuser 465, such as a Diffractive Optical Element (DOE), and a lens 470 downstream of the diffuser 465. The engineered diffuser 465 will preferably be designed and/or selected such that the shape of the beam exiting the engineered diffuser 465 will resemble the shape of the mixing optical fiber 475 and/or the delivery optical fiber 510. For example, if it is desired that the shape of the beam exiting the engineered diffuser 465 be circular, then it may be desirable to use P.N.: RH-217-U-Y-A manufactured by Holo/Or Ltd.13B Einstein Street, Science Park, Ness Ziona, 7403617Israel because the engineered diffuser outputs a circular beam. The specifications for this diffuser are as follows:

as an alternative example, if it is desired that the shape of the beam exiting the engineered diffuser 465 is square, then it may be desired to use a p.n.: HM-271-U-Y-A, because the engineered diffuser outputs a square beam. The specifications of the diffuser are as follows:

as mentioned above, the diffuser lens assembly 460 may include an engineered diffuser 465, such as a Diffractive Optical Element (DOE), and a lens 470 downstream of the diffuser 465. The lens 470 may be a 100mm focal length lens that produces a 1.17mm spot that is focused incident on the input face of the coherence blending fiber 475. The coherence mixing fiber 475 generally allows coherent laser light entering the fiber to become out of phase due to the relatively long length and large diameter of the mixing fiber, thereby emitting a portion of the light that is time delayed relative to other portions. Photons of light that enter the fiber and follow the shortest possible path down the center of the fiber have a much shorter path length than photons that enter the fiber at a steeper angle and continuously bounce off the inner wall of the fiber. Due to the different angles of the photons entering the fiber and the length of the fiber, the coherence of the laser light is mixed and/or scrambled at the output, thereby producing a resulting beam of light that is less coherent than the beam of light entering the hybrid fiber. When this less coherent light is launched into a smaller delivery fiber, the ability to achieve constructive interference light is greatly reduced. The coherence mixing fiber 475 may be a 1.5mm core diameter by 1.5 meter long fused silica multimode fiber. The light exiting the hybrid fiber 475 is collimated using a collimator 480, which may include two focal length lenses 485, 490. For example, lens 485 may be a 75mm focal length lens and lens 490 may be a 25mm focal length lens.

The pulse width of the beam entering and/or exiting the diffuser lens assembly 460 is measured using a pulse detector 465, such as a Thorlabs DET10A photodiode (Thorlabs, Newton, NJ.). Pulse detector 465 also triggers an oscilloscope for counting pulses during a tissue ablation experiment. The beam exiting the diffuser lens assembly 460 enters the delivery fiber 510 and is measured by the energy detector 495. An example of an energy detector 495 is a Gentec Maestro energy meter (Gentec-EO, Lake Oswego, OR.). An example of delivery fiber 510 includes a UV graded fused silica core and a cladding with a polyimide buffer coating, where the fiber has a 1.1 to 1 core-to-cladding ratio and a.22 numerical aperture (polymicro technologies, Phoenix, AZ). Although the delivery fiber 510 in fig. 5 is described as a single fiber, the delivery fiber 510 may alternatively be a bundle of fibers 205 in the laser catheter 150, as described above with respect to fig. 1, 2A, 2B, 3, and 4.

Coherency mixing paradigm

Using the ablation system 400 in FIG. 5, including the use of the coherent blending method created by incorporating the coherent blending fiber 475 into such a system, corresponds to 150mJ/mm at 20Hz²Energy output of up to 42mJ of flux is consistently achieved through a 600 μm core diameter fiber. The coupling efficiency from the laser output to the 600 μm fiber was approximately 30%. 150mJ/mm of optical fiber reported in these results²Limited by the 140mJ laser output. This transmission test was repeated 5 times with a duration of 5 minutes per run and resulted in 0 fiber failures. That is, the optical fiber is not broken or becomes damaged due to light that exceeds the damage threshold of the fused silica material from which the optical fiber is constructed.

Referring to fig. 6, an ablation system 500 of the present disclosure is shown that includes a unit for stretching the pulse width of the beam. By stretching the width of the pulses of the original laser beam and creating a resulting laser beam, the peak power of the resulting light pulse(s) can be reduced relative to the peak power of the original light pulse while maintaining the overall energy contained in the original pulse. Likewise, by reducing the peak power of the original pulse, higher energy levels can be delivered through the fiber. The unit for stretching the pulse width of the beams includes splitting one beam into two beams, passing one of the split beams through an optical delay loop, and recombining the split beams into a resulting beam.

With continued reference to fig. 6, the ablation system 500 is similar to the ablation system 400 of fig. 5 in that the optical components upstream of the wave plate 520 in fig. 6 are the same as the optical components upstream of the diffuser lens assembly 460 in fig. 5. For the sake of brevity, those optical components will not be discussed again with respect to fig. 5. The ablation system in fig. 6 includes a waveplate 520 between the shutter 455 and the beam splitter 525. By rotating the wave plate 455, the transmission and/or reflection characteristics of the split beams exiting the beam splitter 525, such as the energy intensity of the split beams and the ratio of the split beams, can be adjusted, thereby allowing modification of the heights or amplitudes of the pulses 705 and 710 in fig. 7A and 7B such that the amplitudes of the pulses are the same or similar. Thus, the resulting pulse 715 has an effective width that has a more relatively uniform and similar amplitude.

The means for stretching the pulse width of the beam may comprise a beam splitter 525 and a series of mirrors 530, 535, 540, 545. The series of mirrors are designed to create an optical path that forces the beam in the optical delay ring to travel a certain distance in order to create a predetermined time delay. For example, a 120 inch optical path length may create a predetermined time delay of about 10 nsec. A longer optical path length will create a longer time delay and a shorter optical path length will create a shorter time delay. The present disclosure contemplates the use of other optical path lengths to create time delays other than 10 nsec. One way to adjust the optical path length and time delay includes moving one or all of the mirrors 530, 535, 540, 545. Although all mirrors 530, 535, 540, 545 may be fixed or movable, fig. 6 illustrates an example of a mirror 535 that is capable of translating axially, thereby allowing adjustment(s) of the length of the optical delay path and the corresponding distance between the peaks of the pulses.

The optical delay loop begins with a beam splitter 525 that splits the original beam entering the beam splitter 525 into two beams: one of the two beams travels through an optical delay ring; and the other of the two beams does not enter the ring and is directed to mirror 550 and collimator 480. After the beam traveling through the delay loop passes there, the beam splitter 525 recombines the beam passing through the delay loop with the beam not entering the delay loop, thereby creating a resulting beam. And when the two separate beams are recombined by the beam splitter 525, the resulting beam will include the same energy as the original beam entering the beam splitter 525, but the peak power of the resulting beam will be substantially reduced (e.g., less than half the peak power of the original beam). The peak power of the resulting beam is substantially reduced compared to the original beam entering the beam splitter 525 because the optical delay loop causes the beam passing through the delay loop to overlap with the portion of the beam that did not enter the optical delay loop at the predetermined time such that the peak power levels of the two portions are offset by the predetermined time, thereby creating a resulting beam that appears to have a longer pulse width because the peak energy levels of the two separate beams are adjacent to each other and appear to be a single peak for a longer duration.

Referring to fig. 7A, an energy signal is depicted emanating from beam splitter 525 toward mirror 550 in the ablation system depicted in fig. 6. Assuming that beam splitter 525 is an 40/60 beam splitter, beam splitter 525 receives the original beam from wave plate 520 and splits the original beam into two beams, wherein one beam has 40 percent of the energy initially entering beam splitter 525, does not pass through the optical delay loop and is directed to mirror 550, and the other split beam has about 60 percent of the energy initially entering beam splitter 525 and passes through the optical delay loop. This energy signal 705 in fig. 7A represents a split beam that does not pass through the optical delay loop, and the beam has a pulse width of about 7.5 nanoseconds (nsec). Thus, the original beam entering beam splitter 525 will have a peak power that is greater than about 2.5 times the peak power shown in fig. 7A, but the pulse width of the original energy signal will still be about 7.5 nsec. Thus, the energy produced by the signal in fig. 7A is about 40 percent of the energy of the original signal entering beam splitter 525. Thus, 60 percent of the energy entering beam splitter 525 is in the split beam entering the time delay loop. Although 40/60 beam splitters are discussed, the scope of the present disclosure includes other beam splitters having other ratios, such as 5/95, 10/90, 15/85, 20/80, 25/75, 30/70, 36/65, 45/55, 50/50, 55/45, 60/40, 65/35, 70/30, 75/25, 80/20, 85/25, 90/10, 95/5, and any other ratio(s). Likewise, a beam splitter receiving the original beam can split the original beam into two beams, and one beam passing through the optical delay loop can have any percentage of the energy initially entering the beam splitter, and the other split beam can have the remaining percentage of the energy and not pass through the optical delay loop. Other ratios using the beam splitter will adjust the peak energy of the resulting signal.

Referring to fig. 7B, a resulting energy signal emitted from the ablation system depicted in fig. 6 is shown, wherein the resulting energy signal is a combination of a split beam that does not enter the time delay loop and has approximately 40 percent of the energy initially entering the beam splitter 525 and a split beam that enters the time delay loop containing the remaining energy that passed through the time delay loop. As shown in fig. 7B, a first peak 705 is associated with a beam or pulse that does not pass through the optical delay loop and a second peak 710 is associated with a beam or pulse that passes through the optical delay loop. As can be seen by those skilled in the art, the two peaks have substantially the same height, which means that each pulse has substantially the same energy, and when the two pulses are combined, the resulting signal has substantially the same energy entering the beam splitter 525, but the peak energy of the resulting signal is reduced and spread over a longer duration 715 having a stretched pulse width (15ns) effectively twice the pulse width (7.5ns) entering the beam splitter. Although this example illustrates stretching the width of the original pulse to a pulse width in the resulting beam that is twice as long, the present disclosure contemplates stretching the width of the original pulse to other lengths, such as any increment between 1 and 10.

Referring again to fig. 6, the ablation system 500 is similar to the ablation system 400 of fig. 5 except that the coherence mixing fiber 475 of fig. 5 is replaced with a unit for stretching the pulse width of the beam, and the ablation system 500 of fig. 6 also includes a waveplate 520 between the shutter 455 and the beam splitter 525. The means for stretching the pulse width of the beam may comprise a beam splitter 525 and a series of mirrors 530, 535, 540, 545. The series of mirrors are designed to create a predetermined time delay of about 10nsec over an optical path length of about 120 inches. It may also be desirable to axially translate one or more of the mirrors, such as mirror 535, thereby allowing adjustment(s) of the length of the optical delay path and the corresponding distance between the peaks of the pulses.

As discussed above, the engineered diffuser 465 assists in focusing the beam into a desired shape, such as a circular shape or a square shape. An engineering diffuser 465 is also included in the ablation system 500 of fig. 6 such that the engineering diffuser 465 is located downstream of the means for stretching the pulse width of the beam. The combination of such cells and the engineered diffuser 465 allows the ablation system 500 to output a resulting beam with increased symmetry and uniformity as compared to the resulting beam exiting the ablation system 500 without the engineered diffuser. As depicted in fig. 8A, the energy density of the beam produced by the engineered diffuser 465 outputting a circular beam is symmetric and relatively uniform, and as depicted in fig. 8B, the energy density of the beam produced by the engineered diffuser 465 outputting a square beam is symmetric and relatively uniform. Although delivery fiber 510 in fig. 6 may be a single fiber, delivery fiber 510 may alternatively be a bundle of fibers 205 in laser catheter 150, as described above with respect to fig. 1, 2A, 2B, 3, and 4.

Pulse width stretching example 1

Using the above described pulsed tensile initiation method with 355nm laser, energy outputs of up to 56mJ at 20Hz were achieved through a single 600 μm optical fiber. The output energy corresponds to 200mJ/mm²The flux of (c). The coupling efficiency from the laser output to the 600 μm fiber was in the range of 40%. The achieved fiber output energy is limited by the 140mJ laser output energy. This transmission test was repeated 5 times with a duration of 5 minutes per run and resulted in 0 fiber failures.

Pulse width stretching example 2

Using the pulsed draw initiation method described above with 355nm laser, 2.0mm (97X 100 μm fiber)Core diameter fiber) multi-fiber conduit to correspond to 55mJ/mm²The energy of 43.5mJ of flux of (A) was tested in air. The coupling efficiency from the laser output to the multifiber guide is approximately 31%. The achieved fiber output energy is limited by the total energy available using this launch method. No damage to the fiber at the coupler, tip or central axis of the catheter was observed. This transmission test was repeated 5 times with a duration of 5 minutes per run and resulted in 0 fiber failures. The lack of fiber damage observed in section 3.2 and lacking using this initiation method is believed to be due to the homogenized input beam profile achieved with the placement of the DOE before the fiber coupling lens.

Tissue ablation paradigm

To perform a 355nm laser to 308nm light tissue ablation comparison, fresh porcine aortic tissue was used. The organization is delivered via overnight delivery holidays. It was placed in a bag with saline and stored at 15 ℃ until use. All tissues were tested over 5 days of rest to limit tissue degeneration prior to testing. When the comparison results are presented, the samples are derived from the same tissue and the tests are performed on the same day.

The porcine aorta was trimmed to produce a flat tissue sample that was consistent in thickness. The sample was then nailed to the surface of an inner film of a cork sheet. The cork plate has through holes for tissue crossing. The cork and tissue samples were then placed in a petri dish and submerged in saline. The petri dish was then placed in numerical proportion to set and monitor the downward force of the fiber. The fiber is held in a teeter-totter type balance that allows fine tuning of the applied downward force.

A shutter in the laser beam path prior to fiber coupling is opened to allow light into the delivery fiber. The tissue is monitored as the fiber passes through it. When the fiber exits through the back side of the tissue, the shutter is closed and the number of pulses for penetration is recorded. The tissue was removed after testing and the thickness was measured in the location of the ablation holes using a dial thickness gauge. Then, the penetration per pulse is calculated and compared.

The tissue test was performed using a flux emitting 60mJ/mm2 and a flux for 355nm and 30 nm8nm, at a pulse repetition rate of 20Hz, is performed on a single 600 μm fiber. Typically, 60mJ/mm²The flux output represents the energy flux setting used by physicians currently using spectra CVX excimer lasers. The 20Hz pulse repetition rate was chosen to fall within the specifications of the 355nm laser being tested. The test was performed with 4 different downward forces applied to the fiber. Ten fully penetrating samples were then collected at each downward force setting for 355nm and 308 nm. After testing, tissue samples were photographed at 50 x magnification and fixed in 10% formalin solution.

The tissue samples are sent to an external laboratory and processed for histopathology. The slide for each specimen was stained with hematoxylin and eosin (H & E) for light microscopy evaluation and imaging. Fig. 9 shows comparative tissue penetration rates between 355nm and 308nm at different applied fiber forces using the method(s) described in the tissue ablation example. Penetration of 308nm light is approximately 3 times faster with 1gr of downward force and approximately 8 times faster with 10gr of downward force on the fiber. The appearance of the ablation holes is similar at 1gr of force, but smaller for the 308nm holes created with 10gr of downward force on the fiber. These test results were analyzed for penetration only.

During testing, the far end fiber fault was observed 4 times from among 40 samples during 355nm sample testing and 0 times from among 40 samples during 308nm testing. It is believed that the fiber damage is a result of the higher peak power of the short pulse width 355nm laser.

FIG. 10A is an image of a hole ablated in the porcine aorta with a single 600 micron fiber applying a downward force of about 5g and using a 355nm laser system similar or identical to the laser system illustrated in FIG. 6, where the fiber outputs about 60mJ/mm at 20Hz². FIG. 10B is an image of a hole ablated in the porcine aorta with a single 600 micron fiber applying a downward force of about 5g and using a laser system 308nm laser system, where the fiber outputs about 60mJ/mm at 20Hz². The ablation holes in fig. 10A and 10B have a similar appearance and are not viewed at 50 x magnificationShowing visible charring.

FIG. 11A is an image of a histological cross-section of a hole ablated in the porcine aorta with a single 600 micron fiber applying a downward force of about 5g and using a 355nm laser system similar to or the same as the laser system illustrated in FIG. 6, wherein the fiber outputs about 60mJ/mm at 20Hz². FIG. 11B is an image of a histological cross-section of a hole ablated in the porcine aorta with a single 600 micron fiber applying a downward force of about 5g and using a 308nm laser system, where the fiber outputs about 60mJ/mm at 20Hz². Many variations and modifications of the present disclosure may be used. It will be possible to provide some of the features of the present disclosure without providing others. Fig. 11A and 11B show that the laser-produced holes are thermally generated degenerations through the full thickness of the vessel wall with the resulting local tissue disruption and through (lining) defects. Fiber penetration is initiated from the intimal surface of the aortic sample.

Referring to fig. 12, a further alternative ablation system 600 of the present disclosure is shown. The ablation system 600 is similar to the ablation system 500 of fig. 6, except that the means for stretching the pulse width of the beam in fig. 12 may include a beam splitter 525 and a sufficient length of optical coherence fiber 610 to cause the split beam to pass there through and instead create the desired predetermined time delay using the beam splitter 525 and a series of mirrors 530, 535, 540, 545 as shown in fig. 6. With continued reference to FIG. 2, it may be desirable to include a coupling lens 605 between the beam splitter 525 and the optical coherence mixing fiber 610, and it may be desirable to include a collimator 615, the collimator 615 including two optical lenses 620, 625 to collimate the light as it re-enters the optical path (including the beam splitter). Incorporating the optical coherence blending fiber 610 into the unit for stretching the pulse width of the beam provides the ablation system with the following advantages: by spreading the energy over a longer duration, the peak energy of the original beam is reduced and a more uniform signal is created, thereby minimizing potential damage to the delivery fiber(s) 510.

In various aspects, embodiments, and/or configurations, the present disclosure includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various aspects, embodiments, configuration embodiments, subcombinations, and/or subsets thereof. Those of skill in the art will understand how to make and use the disclosed aspects, embodiments, and/or configurations after understanding the present disclosure. In various aspects, embodiments, and/or configurations, the disclosure includes providing devices and processes in the absence of items not depicted and/or described herein or in various aspects, embodiments, and/or configurations hereof, including in the absence of such items as may have been used in various devices or processes, e.g., for improving performance, achieving ease and/or reducing cost of implementation.

The foregoing discussion has been presented for purposes of illustration and description. The foregoing is not intended to limit the disclosure to the form(s) disclosed herein. In the foregoing summary, for example, various features of the disclosure are grouped together in one or more aspects, embodiments, and/or configurations for the purpose of streamlining the disclosure. Features of aspects, embodiments and/or configurations of the present disclosure may be combined in alternative aspects, embodiments and/or configurations other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention that the claims require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed aspect, embodiment, and/or configuration. Thus, the following claims are hereby incorporated into this summary, with each claim standing on its own as a separate embodiment of the disclosure.

Moreover, although the description has included description of one or more aspects, embodiments, and/or configurations and certain variations and modifications, other variations, combinations, and modifications are within the scope of the disclosure, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to include alternative aspects, embodiments, and/or configurations, to the extent permitted, including interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such interchangeable, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.