阅读说明：本技术 准分子激光器放电腔的窗片结构及准分子激光器 (Window sheet structure of excimer laser discharge cavity and excimer laser ) 是由 赵江山 郭馨 王倩 刘广义 刘斌 沙鹏飞 詹绍通 刘明雷 胡馨月 江锐 于 2020-06-30 设计创作，主要内容包括：本发明涉及准分子激光器领域,具体涉及一种准分子激光器放电腔的窗片结构,包括：光学窗片V1、V2、V3、V4；其中V2、V3为内部光学窗片,V1、V4为外部光学窗片,单侧的光学窗片V1、V2和单侧的光学窗片V3、V4在放电腔体两侧对称布置。本发明中双光学窗片结构设计极大改善了以往单一光学窗片结构容易因为应力变形所导致的使用寿命下降和传输效能降低的问题。另单侧的光学窗片V1、V2和单侧的光学窗片V3、V4在放电腔体两侧对称布置,且各光学窗片接近布儒斯特角设置可以起到有效的激光传输偏振特性增强作用。双光学窗片结构的设计对于腔体内部气体密封特性也得到显著的改善。本发明能够有效提升光学窗片使用寿命,提升激光传输效能。(The invention relates to the field of excimer lasers, in particular to a window sheet structure of an excimer laser discharge cavity, which comprises: optical window pieces V1, V2, V3, V4; wherein V2, V3 are inner optical window sheets, V1, V4 are outer optical window sheets, and one-sided optical window sheets V1, V2 and one-sided optical window sheets V3, V4 are symmetrically arranged at two sides of the discharge cavity. The double-optical window structure design greatly solves the problems that the service life of the traditional single-optical window structure is easy to be reduced and the transmission efficiency is easy to be reduced due to stress deformation. The other single-sided optical window sheets V1 and V2 and the single-sided optical window sheets V3 and V4 are symmetrically arranged on two sides of the discharge cavity, and the arrangement of the optical window sheets close to the Brewster angle can play an effective role in enhancing the polarization characteristic of laser transmission. The design of the dual optical window structure also provides significant improvement in the gas sealing characteristics inside the cavity. The invention can effectively prolong the service life of the optical window and improve the laser transmission efficiency.)

1. A window structure of excimer laser discharge cavity is characterized in that: the method comprises the following steps: optical window pieces V1, V2, V3, V4; wherein V2, V3 are inner optical window sheets, V1, V4 are outer optical window sheets, and one-sided optical window sheets V1, V2 and one-sided optical window sheets V3, V4 are symmetrically arranged at two sides of the discharge cavity.

2. The louver structure of an excimer laser discharge chamber of claim 1, wherein: the included angle between the normal lines of the optical window pieces V1 and V2 on the single side and the transmission direction of the laser is 55-58 degrees; or the normal of one of the optical window sheets V1 and V2 on one side forms an included angle of 55-58 degrees with the transmission direction of the laser, and the normal of the other optical window sheet is the same with the transmission direction of the laser;

the included angle between the normal lines of the optical window pieces V3 and V4 on one side and the transmission direction of the laser is 55-58; or the normal line of one of the optical window sheets V3 and V4 on one side forms an included angle of 55-58 degrees with the transmission direction of the laser, and the normal line of the other optical window sheet is the same with the transmission direction of the laser.

3. The louver structure of an excimer laser discharge chamber of claim 2, wherein: the included angle between the normal lines of the optical window pieces V1 and V2 on the single side and the transmission direction of the laser is a Brewster angle; or the normal of one of the optical window sheets V1 and V2 on one side forms an included angle with the transmission direction of the laser light, the included angle is the Brewster angle, and the normal of the other optical window sheet is the same with the transmission direction of the laser light;

the included angle between the normal lines of the optical window pieces V3 and V4 on one side and the transmission direction of the laser is a Brewster angle; or the normal of one of the optical window pieces V3 and V4 on one side forms the Brewster angle with the transmission direction of the laser light, and the normal of the other optical window piece is the same with the transmission direction of the laser light.

4. A louver structure for an excimer laser discharge chamber according to any one of claims 1 to 3, wherein: the optical window sheets V1 and V2 on one side are arranged in parallel or in axial symmetry; the optical sheets V3 and V4 on one side are arranged in parallel or axisymmetric.

5. A louver structure for an excimer laser discharge chamber according to any one of claims 1 to 3, wherein: when the normal of one of the optical window sheets on one side is the same as the transmission direction of the laser, the distance between the horizontal middle lines of the two window sheets on one side is 0-20 mm;

when the optical window pieces V1 and V2 on one side are arranged in parallel, the distance between the optical window pieces V1 and V2 is 10-20 mm; when the optical window pieces V1 and V2 on one side are arranged in an axisymmetric manner, the distance between the horizontal middle lines of the optical window pieces V1 and V2 is 10-20 mm;

when the optical window pieces V3 and V4 on one side are arranged in parallel, the distance between the optical window pieces V3 and V4 is 10-20 mm; when the optical sheets V3, V4 on one side are arranged axisymmetrically, the distance between the horizontal center lines of the optical sheets V3, V4 is 10-20 mm.

6. The louver structure of an excimer laser discharge chamber of claim 1, wherein: the space between the outer optical louver V1 and the inner optical louver V2 and the space between the outer optical louver V4 and the inner optical louver V3 are filled with inert gas.

7. The louver structure of an excimer laser discharge chamber of claim 6, wherein: the ratio of the refractive index of the medium in the discharge cavity to the refractive index of the medium between the inner and outer optical window sheets is the same as the ratio of the refractive index of the medium between the inner and outer optical window sheets to the refractive index of the outside air.

8. The louver structure of an excimer laser discharge chamber of claim 6, wherein: the filling pressure of the inert gas is 0-3 bar.

9. The louver structure of an excimer laser discharge chamber of claim 1, wherein: the inner optical window sheets V2 and V3 are isolated and sealed optical window sheets and are communicated with the discharge cavity; the external optical louvers V1, V4 are leading output optical louvers and communicate with the external environment.

10. An excimer laser characterized by: a louver structure comprising an excimer laser discharge chamber as claimed in any one of claims 1 to 9.

Technical Field

The invention relates to the field of excimer lasers, in particular to a window sheet structure of an excimer laser discharge cavity and an excimer laser.

Background

The effective application and lifetime characteristics of brewster optical panes are one of the important issues in the gas laser technology research. The main working principle of the gas excimer laser is the energy level transition and particle number inversion process caused by the breakdown of working gas under the condition of high-voltage discharge pumping, and finally laser radiation corresponding to the energy level bandwidth of a working medium is formed. The discharge cavity is a place for realizing excitation-inversion-radiation by a gas working medium. For excimer lasers used in the ultraviolet (wavelength <400nm), an optical window is usually set at an angle close to brewster to obtain a certain polarization transmission characteristic. The traditional discharge cavity generally adopts a single optical window with a Brewster angle as a window, mainly aims to play the roles of gas sealing of the discharge cavity and directional resonance guiding of laser radiation, and meanwhile, the arrangement mode of the Brewster angle plays a certain role in polarization purification in the laser transmission process.

The high-voltage discharge process with gas as working medium is the basis for realizing laser radiation and is limited by electro-optic conversion efficiency, only 1% -2% of electric energy is injected and converted into final laser output, and the rest of a large amount of energy is injected and converted into heat and exists in a discharge cavity. Meanwhile, in order to ensure the effective and stable discharge process, the matching of electric Paschen characteristics between the discharge voltage, the discharge electrode and the working gas pressure is required, and the gas pressure of a discharge cavity is usually 2-6 bar. In addition, for some high repetition rate pulsed laser applications, the gaseous working medium needs to establish a high-speed circulating pneumatic flow field.

For the analysis, an extreme environment of extreme high temperature (1000 ℃ instantaneous high temperature) and high pressure (2-6bar) can be formed inside the gas discharge cavity in the discharge operation process, for a Brewster optical window sealed by the cavity, the high-temperature and high-pressure environment inside the cavity is arranged on the inner side of the optical window, the room temperature (20 ℃) and normal pressure (1bar) are arranged on the outer side of the optical window, and huge temperature and pressure differences can be formed on the two sides of the optical window, so that the optical window is deformed under the stress action, the laser transmission efficiency, the polarization characteristic and the like are influenced, and the service life of elements is prolonged. Meanwhile, in the discharging process, the gasification decomposition product particles of the electrode and the wall material in the cavity are filled in the cavity, the optical window is contaminated by the dispersion splashing process, so that the service life of the optical window is greatly shortened, and the laser with high strength, high repetition frequency and long working time even can cause the optical window to be cracked seriously, so that the service life of the optical window, the laser transmission efficiency and the gas sealing characteristic are influenced.

Fig. 1 is a schematic diagram of a resonant cavity structure in a conventional gas excimer laser. The discharge cavity DC is filled with working gas, laser radiation is generated under the excitation of a power supply PS, the laser radiation is emitted through an optical window W1 and an optical window W2, then the laser radiation is transmitted to and fro under the action of a resonant cavity consisting of a resonant cavity end reflecting mirror M1 and a resonant cavity output coupling mirror M2, and laser output is finally formed through the mode selection and gain amplification processes. The optical window W1 and the optical window W2 have a certain purification effect on the polarization characteristics of the transmission laser under the Brewster angle setting condition.

Fig. 2 is a schematic diagram of a discharge cavity structure in a conventional gas excimer laser. The discharge chamber DC is filled with a working gas, and excited by the power supply PS, generates laser radiation, and exits through the optical window W1 and the optical window W2. The discharge cavity DC is a place where high-voltage working gas carries out high-voltage discharge, and the optical window sheets W1 and W2 play a role in sealing gas inside the cavity and are symmetrically arranged to be used as direction selection of laser radiation guide output. Working gas in the discharge cavity DC forms laser radiation under the action of high-voltage discharge excitation, and simultaneously a large amount of energy is converted into heat to be stored in the cavity. The interiors of the optical window sheets W1 and W2 on the two sides of the discharge cavity DC are communicated with the environment in the cavity under the discharge condition, and are in a high-temperature and high-pressure state.

The outer parts of the optical window W1 and the optical window W2 are communicated with the working environment of the laser and are in a normal temperature and normal pressure state, and the temperature and pressure difference between the two sides of the two optical windows can cause the generation of corresponding stress deformation, thereby reducing the service life and the transmission efficiency of the optical window. Meanwhile, the high-voltage gas discharge process is accompanied with the gasification and dissociation of the electrode and the wall material in the cavity to form discharge product particles which are dispersed in the cavity. The optical window piece contaminated with dust particles can affect the laser transmission characteristics, and in severe cases, the optical window piece fails or even is broken due to high repetition frequency and high-intensity laser transmission and long-time working, so that the service life and the sealing characteristics are affected, the structural design of the optical window piece is effectively improved, and the service life, the transmission efficiency and the sealing characteristics of the optical window piece are very important for improving the operating efficiency of the gas excimer laser.

Disclosure of Invention

The embodiment of the invention provides a window sheet structure of an excimer laser discharge cavity, which at least solves the technical problem of low laser transmission efficiency of the existing gas excimer laser.

According to an embodiment of the present invention, there is provided a window structure of an excimer laser discharge chamber, including: optical window pieces V1, V2, V3, V4; wherein V2, V3 are inner optical window sheets, V1, V4 are outer optical window sheets, and one-sided optical window sheets V1, V2 and one-sided optical window sheets V3, V4 are symmetrically arranged at two sides of the discharge cavity.

Furthermore, the included angle between the normal lines of the optical window pieces V1 and V2 on the single side and the transmission direction of the laser is 55-58 degrees; or the normal of one of the optical window sheets V1 and V2 on one side forms an included angle of 55-58 degrees with the transmission direction of the laser, and the normal of the other optical window sheet is the same with the transmission direction of the laser;

the included angle between the normal lines of the optical window pieces V3 and V4 on one side and the transmission direction of the laser is 55-58; or the normal line of one of the optical window sheets V3 and V4 on one side forms an included angle of 55-58 degrees with the transmission direction of the laser, and the normal line of the other optical window sheet is the same with the transmission direction of the laser.

Furthermore, the included angle between the normal lines of the optical window pieces V1 and V2 on the single side and the transmission direction of the laser is the Brewster angle; or the normal of one of the optical window sheets V1 and V2 on one side forms an included angle with the transmission direction of the laser light, the included angle is the Brewster angle, and the normal of the other optical window sheet is the same with the transmission direction of the laser light;

the included angle between the normal lines of the optical window pieces V3 and V4 on one side and the transmission direction of the laser is a Brewster angle; or the normal of one of the optical window pieces V3 and V4 on one side forms the Brewster angle with the transmission direction of the laser light, and the normal of the other optical window piece is the same with the transmission direction of the laser light.

Furthermore, the optical window pieces V1 and V2 on one side are arranged in parallel or in axial symmetry; the optical sheets V3 and V4 on one side are arranged in parallel or axisymmetric.

Further, when the normal of one of the optical window sheets on one side is the same as the transmission direction of the laser, the distance between the horizontal middle lines of the two window sheets on one side is 0-20 mm;

when the optical window pieces V1 and V2 on one side are arranged in parallel, the distance between the optical window pieces V1 and V2 is 10-20 mm; when the optical window pieces V1 and V2 on one side are arranged in an axisymmetric manner, the distance between the horizontal middle lines of the optical window pieces V1 and V2 is 10-20 mm;

when the optical window pieces V3 and V4 on one side are arranged in parallel, the distance between the optical window pieces V3 and V4 is 10-20 mm; when the optical sheets V3, V4 on one side are arranged axisymmetrically, the distance between the horizontal center lines of the optical sheets V3, V4 is 10-20 mm.

Further, the space between the outer optical louver V1 and the inner optical louver V2 and the space between the outer optical louver V4 and the inner optical louver V3 are filled with inert gas.

Further, the ratio of the refractive index of the medium in the discharge cavity to the refractive index of the medium between the inner and outer optical sheets is the same as the ratio of the refractive index of the medium between the inner and outer optical sheets to the refractive index of the outside air.

Further, the filling pressure of the inert gas is 0 to 3 bar.

Further, the filling pressure of the inert gas is 2 bar.

Further, the inner optical window sheets V2 and V3 are isolation sealing optical window sheets and are communicated with the discharge cavity.

Further, the external optical louvers V1, V4 are leading output optical louvers, and communicate with the external environment.

In the window structure of the excimer laser discharge cavity in the embodiment of the invention, the double-optical window structure design greatly improves the problems of service life reduction and transmission efficiency reduction caused by stress deformation of the traditional single optical window structure. The other single-sided optical window sheets V1 and V2 and the single-sided optical window sheets V3 and V4 are symmetrically arranged on two sides of the discharge cavity, and the arrangement of the optical window sheets close to the Brewster angle can play an effective role in enhancing the polarization characteristic of laser transmission. The design of the dual optical window structure also provides significant improvement in the gas sealing characteristics inside the cavity. The invention can effectively prolong the service life of the optical window and improve the laser transmission efficiency.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a schematic diagram of a resonant cavity structure in a conventional gas excimer laser;

FIG. 2 is a schematic diagram of a discharge cavity of a conventional gas excimer laser;

FIG. 3 is a schematic view of a dual optical louver configuration according to the present application, shown in a parallel configuration;

FIG. 4 is a schematic view of a dual optical louver configuration according to the present application, shown schematically as I, in an axisymmetric arrangement;

FIG. 5 is a schematic view II of a dual optical louver configuration according to the present application, shown in a parallel configuration;

fig. 6 is a schematic diagram i of the dual optical window structure proposed in the present application, which is designed as an outer window V1, the normal of V4 is the same as the transmission direction of the laser, and the included angle between the normal of the inner windows V2, V3 and the transmission direction of the laser is set to be close to the brewster angle;

FIG. 7 is a schematic view II of the dual optical louver structure proposed in the present application, designed as an outer louver V1, with the normal to V4 being the same as the laser propagation direction and the inner louvers V2, V3 having an angle with the laser propagation direction that is set near the Brewster angle;

fig. 8 is a schematic diagram iii of the proposed dual optical louver structure of the present application, in which the external louver V1 has a normal line of V4 that is the same as the transmission direction of the laser light, and the internal louvers V2 and V3 have an angle with the transmission direction of the laser light that is set close to the brewster angle.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In view of the application condition of the Brewster optical window in the existing gas excimer laser, the technical scheme of the application mainly adopts the design of a single-side double-optical window structure, the single-side optical window is divided into an inner optical window and an outer optical window, the two optical windows on two sides are symmetrically arranged, the distance between the two optical windows on the same side is 10-20mm, inert gas is blown and filled, the gas pressure value is 1-3bar, preferably 2bar, and the mutual arrangement mode of the two optical windows on one side can be freely selected within the range of being close to a Brewster angle, such as 55-58 degrees, and can be parallel to the Brewster angle, or axially symmetric to the same direction and different directions of other angles; or one of the two optical panes on one side is disposed at approximately the brewster angle and the other is disposed at the other angle.

Compared with the existing design, the temperature and pressure difference at two sides of the optical window is reduced, the stress deformation influence of the optical window is reduced, and the service life is prolonged. Compared with the prior design, the external optical window sheet of the invention is used as a guide output optical window sheet and communicated with the external environment, the temperature and pressure difference at two sides of the external optical window sheet is smaller, and the stress deformation influence of the external optical window sheet is reduced. Meanwhile, due to the isolation and sealing effect of the internal optical window, the pollution influence of a discharge generation product on the external optical window is effectively reduced, and the laser radiation guided by the internal optical window can be effectively transmitted, so that the service life of the optical window is greatly prolonged.

The design of the single-side double-optical window structure greatly improves the problems that the service life of the traditional single-side single-optical window structure is easy to be reduced and the transmission efficiency is reduced due to stress deformation. In addition, when the mutual setting angle of the internal optical window and the external optical window is close to the Brewster angle, the effective laser transmission polarization characteristic enhancement effect can be achieved, and certainly, if the mutual setting angle of the internal optical window and the external optical window is the Brewster angle, the laser transmission polarization characteristic enhancement effect is best. The design of the dual optical window structure also provides significant improvement in the gas sealing characteristics inside the cavity. The invention can effectively prolong the service life of the optical window and improve the laser transmission efficiency.

The structure of the window of the excimer laser discharge chamber of the present invention is described in detail below with specific examples.

Example 1

According to an embodiment of the present invention, there is provided a window structure of an excimer laser discharge chamber, as shown in fig. 3 to 8, including: optical window pieces V1, V2, V3, V4; wherein V2, V3 are inner optical window sheets, V1, V4 are outer optical window sheets, and one-sided optical window sheets V1, V2 and one-sided optical window sheets V3, V4 are symmetrically arranged at two sides of the discharge cavity.

In the window structure of the excimer laser discharge cavity in the embodiment of the invention, the double-optical window structure design greatly improves the problems of service life reduction and transmission efficiency reduction caused by stress deformation of the traditional single optical window structure. In addition, when the single-side optical window sheets V1 and V2 and the single-side optical window sheets V3 and V4 are symmetrically arranged on two sides of the discharge cavity, the effective laser transmission polarization characteristic enhancement effect can be achieved. The design of the dual optical window structure also provides significant improvement in the gas sealing characteristics inside the cavity. The invention can effectively prolong the service life of the optical window and improve the laser transmission efficiency.

Wherein, the included angle between the normal lines of the optical window sheets V1 and V2 on one side and the transmission direction of the laser is 55-58 degrees; or the normal of one of the optical window sheets V1 and V2 on one side forms an included angle of 55-58 degrees with the transmission direction of the laser, and the normal of the other optical window sheet is the same with the transmission direction of the laser;

the included angle between the normal lines of the optical window pieces V3 and V4 on one side and the transmission direction of the laser is 55-58; or the normal line of one of the optical window sheets V3 and V4 on one side forms an included angle of 55-58 degrees with the transmission direction of the laser, and the normal line of the other optical window sheet is the same with the transmission direction of the laser.

The included angle between the normal lines of the optical window pieces V1 and V2 on one side and the transmission direction of the laser is preferably the Brewster angle; or the normal line of one of the optical window sheets V1 and V2 on one side forms an angle with the transmission direction of the laser light, preferably the angle is Brewster's angle, and the normal line of the other optical window sheet is the same as the transmission direction of the laser light;

the included angle between the normal lines of the optical window pieces V3 and V4 on one side and the transmission direction of the laser is preferably the Brewster angle; or the normal of one of the optical panes V3, V4 on one side is preferably at brewster's angle to the direction of propagation of the laser light, while the normal of the other optical pane is the same as the direction of propagation of the laser light.

Wherein, the optical window sheets V1 and V2 on one side are arranged in parallel or in axial symmetry; the optical sheets V3 and V4 on one side are arranged in parallel or axisymmetric.

When the normal of one of the optical window sheets on one side is the same as the transmission direction of laser, the distance between the horizontal middle lines of the two window sheets on one side is 0-20 mm;

when the optical window pieces V1 and V2 on one side are arranged in parallel, the distance between the optical window pieces V1 and V2 is 10-20 mm; when the optical window pieces V1 and V2 on one side are arranged in an axisymmetric manner, the distance between the horizontal middle lines of the optical window pieces V1 and V2 is 10-20 mm;

when the optical window pieces V3 and V4 on one side are arranged in parallel, the distance between the optical window pieces V3 and V4 is 10-20 mm; when the optical sheets V3, V4 on one side are arranged axisymmetrically, the distance between the horizontal center lines of the optical sheets V3, V4 is 10-20 mm.

The space between the outer optical louver V1 and the inner optical louver V2 and the space between the outer optical louver V4 and the inner optical louver V3 are filled with inert gas.

The ratio of the refractive index of the medium in the discharge cavity to the refractive index of the medium between the inner optical window and the outer optical window is the same as the ratio of the refractive index of the medium between the inner optical window and the outer optical window to the refractive index of the outside air.

Wherein the filling pressure of the inert gas is 0-3 bar.

Wherein, preferably, the filling pressure of the inert gas is 2 bar.

The inner optical window sheets V2 and V3 are isolation sealing optical window sheets and are communicated with the discharge cavity.

The external optical window pieces V1 and V4 are guiding output optical window pieces and are communicated with the external environment.

Specifically, according to an embodiment of the present invention, a window structure of an excimer laser discharge chamber is provided, as shown in fig. 3, with single-sided dual-optical windows arranged in parallel.

The window structure of the laser discharge cavity comprises: optical window pieces V1, V2, V3, V4; wherein V2, V3 are inner optical window sheets, V1, V4 are outer optical window sheets, and one-sided optical window sheets V1, V2 and one-sided optical window sheets V3, V4 are symmetrically arranged at two sides of the discharge cavity.

The discharge chamber DC is filled with working gas, and generates laser radiation under the excitation of the power supply PS. The discharge cavity DC is a place where high-voltage working gas is subjected to high-voltage discharge, and the inner optical window sheets V2 and V3 and the outer optical window sheets V1 and V4 play a role in sealing gas inside the cavity.

In the window structure of the excimer laser discharge cavity in the embodiment of the invention, the design of the single-side double-optical window structure greatly improves the problems of the service life reduction and the transmission efficiency reduction of the traditional single-optical window structure caused by stress deformation.

In fig. 3, the one-sided optical windows V1 and V2 and the one-sided optical windows V3 and V4 are arranged in parallel at an angle close to the brewster angle, and can perform polarization twice, thereby effectively enhancing the polarization characteristics of laser light transmission. The included angle between the normal lines of the optical window pieces V1 and V2 on one side and the transmission direction of the laser is close to the Brewster angle, specifically 55-58 degrees, and the included angle between the normal lines of the optical window pieces V3 and V4 on one side and the transmission direction of the laser is also close to the Brewster angle, specifically 55-58 degrees; when the included angle is the Brewster angle, the polarization enhancement effect is best.

The space between the outer optical window V1 and the inner optical window V2 and the space between the outer optical window V4 and the inner optical window V3 are filled with inert gas IG purging under a certain pressure. The ratio of the refractive index of the medium in the discharge cavity DC to the refractive index of the medium between the inner and outer optical louvers is substantially the same as the ratio of the refractive index of the medium between the inner and outer optical louvers to the refractive index of the outside air.

As the isolated sealed optical window, the internal optical windows V2 and V3 are communicated with the discharge cavity DC, compared with the existing design, the temperature and pressure difference at two sides of the optical window is reduced, the stress deformation influence of the optical window is reduced, and the service life is prolonged; the external optical window pieces V1 and V4 are used as guiding output optical window pieces and communicated with the working environment of an external laser.

The design of the dual louver structure requires inert gas purging and filling between the internal optical louvers and the external optical louvers to ensure effective implementation of the functions of the internal optical louvers and the external optical louvers. The inert gas purge is charged at a pressure of 1-3bar, preferably 2 bar. The distance between the corresponding inner optical window pieces V2 and V3 and the corresponding outer optical window pieces V1 and V4 is 10-20mm, so that the pressure and temperature difference at two sides of the inner optical window pieces can be reduced to a certain extent on the premise of ensuring effective pressure gas sealing, and the service life of the inner optical window pieces is prolonged; meanwhile, under the action of inert gas heat insulation and isolation, the temperatures of the two sides of the external optical window are the same, stress deformation damage caused by temperature and pressure difference is greatly reduced, and the service life is correspondingly prolonged.

The design of the dual-optical window structure greatly improves the problems that the service life of the traditional single-optical window structure is easy to be reduced and the transmission efficiency is easy to be reduced due to stress deformation. In addition, the internal optical window and the external optical window are arranged in parallel at an angle close to the Brewster angle (55 degrees to 58 degrees), so that the effective laser transmission polarization characteristic enhancement effect can be achieved, and when the Brewster angle theta B is arranged in parallel, the polarization enhancement effect is the best. The dual-optical window sheet structure design enables the gas sealing property inside the cavity to be remarkably improved. The invention can effectively prolong the service life of the optical window and improve the laser transmission efficiency.

Fig. 4 is a schematic view of a dual optical louver configuration according to yet another embodiment of the present application, illustrating an example of an axisymmetric arrangement. The dual-optical window of fig. 4 is disposed axisymmetrically and at an angle close to brewster, and specifically, the inner optical windows V2 and V3 and the outer optical windows V1 and V4 are symmetrically disposed at both sides of the cavity, and the two optical windows at one side are disposed axisymmetrically at brewster angle. The single-side internal optical window and the single-side external optical window are arranged in an axial symmetry mode, when the normal direction of the optical window and the laser transmission direction are at Brewster angle theta B (55 degrees to 58 degrees), the included angle between the two single-side optical windows is close to 180 degrees to 2 theta B, at the moment, laser transmission can be carried out twice and related to Brewster angle transmission, a good polarization enhancement effect can be formed, and when the normal direction of the optical window and the laser transmission direction are at Brewster angle theta B, the polarization enhancement effect is best. The space between the outer optical window V1 and the inner optical window V2 and the space between the outer optical window V4 and the inner optical window V3 are purged and filled with inert gas under a certain pressure. The related structural design analysis is consistent with the parallel arrangement content of the angle close to the Brewster shown in the figure 3, and the method is more flexible and diversified in structural design and forms selective application under different structures by matching with an inert gas purging and filling mode.

The inert gas purging and filling pressure is 1-3bar, preferably 2bar, the distance between the corresponding inner optical window pieces V2 and V3 and the corresponding outer optical window pieces V1 and V4 is 10-20mm, namely the distance between the horizontal center lines of the optical window pieces V1 and V2 is 10-20mm, and the distance between the horizontal center lines of the optical window pieces V3 and V4 is 10-20mm, so that the pressure and temperature difference on two sides of the inner optical window pieces can be reduced to a certain extent on the premise of ensuring effective pressure gas sealing, and the service life of the inner optical window pieces is prolonged; meanwhile, under the action of inert gas heat insulation and isolation, the temperatures of the two sides of the external optical window are the same, stress deformation damage caused by temperature and pressure difference is greatly reduced, and the service life is correspondingly prolonged. The design of the dual-optical window structure greatly improves the problems that the service life of the traditional single-optical window structure is easy to be reduced and the transmission efficiency is easy to be reduced due to stress deformation. In addition, the internal optical window and the external optical window are arranged in parallel by adopting an angle (55-58 degrees) close to the Brewster angle, so that the effective laser transmission polarization characteristic enhancement effect can be realized. The dual optical louver structure design also has a significant improvement in the gas sealing characteristics inside the cavity.

Fig. 5 is a schematic diagram of a dual optical louver structure according to yet another embodiment of the present disclosure, and for the example of parallel arrangement, the optical louvers V2 and V3 generate a sub-cavity resonance effect, i.e., the laser oscillates between the optical louver V2 and the optical louver V3, but not between the optical louver V1 and the optical louver V4.

Fig. 6 is a schematic diagram of a dual optical window structure design according to yet another embodiment of the present disclosure, which is a setting example in which a normal of the outer window V1 and the V4 is the same as a transmission direction of laser light, and an included angle between a normal of the inner window V2 and the V3 and the transmission direction of the laser light is close to a brewster angle (55 ° -58 °), where the optical windows V2 and V3 in fig. 6 can achieve a primary polarization effect when being set close to the brewster angle, and can effectively shield a sub-cavity resonance effect from transmission and resonance amplification of the light, and suppress an influence of the transmitted laser light on laser emission during gas discharge in the cavity due to the sub-cavity effect. And because the outer optical window sheets V1 and V4 are vertically arranged, the installation difficulty is low.

Fig. 7 is a schematic diagram of a dual optical louver structure according to yet another embodiment of the present application, in which the normal line of the outer louver V1 and V4 is the same as the transmission direction of the laser light, and the included angle between the normal line of the inner louvers V2 and V3 and the transmission direction of the laser light is set to be close to the brewster angle (55 ° -58 °), and the effect of the structure design shown in fig. 7 is the same as that shown in fig. 6.

Fig. 8 is a schematic diagram of the dual optical louver structure proposed in the present application, which is an example of the arrangement where the normal of the outer louver V1 and V4 is the same as the transmission direction of the laser light, and the included angle between the normal of the inner louver V2 and V3 and the transmission direction of the laser light is close to brewster angle (55 ° -58 °), and the effect of the structure design shown in fig. 8 is the same as that of the structure design shown in fig. 6, which can generate the sub-cavity resonance effect.

The distance between the single-sided optical panes in the examples shown in fig. 5-8 is 10-20mm, i.e., the distance between the horizontal centerlines of the single-sided optical panes is 10-20 mm; and the space between the outer optical window piece V1 and the inner optical window piece V2 and the space between the outer optical window piece V4 and the inner optical window piece V3 are filled with inert gas under certain pressure, and the related structural design is consistent with the embodiment shown in FIG. 3.

The examples shown in fig. 5-8 are consistent with other designs except that the angles of the inner and outer louvers are set as variations of fig. 3.

Example 2

According to another embodiment of the present invention, there is provided a gas excimer laser comprising a louver structure of an excimer laser discharge chamber as defined in any one of the above.

In the gas excimer laser in the embodiment of the invention, the double-optical window structure design greatly improves the problems of service life reduction and transmission efficiency reduction caused by stress deformation of the traditional single optical window structure. In addition, when the single-side optical window sheets V1 and V2 and the single-side optical window sheets V3 and V4 are symmetrically arranged on two sides of the discharge cavity, the effective laser transmission polarization characteristic enhancement effect can be achieved. The design of the dual optical window structure also provides significant improvement in the gas sealing characteristics inside the cavity. The invention can effectively prolong the service life of the optical window and improve the laser transmission efficiency.

The sequence numbers of the above embodiments of the present invention are merely for description and do not represent the order of merits of the embodiments.

In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described system embodiments are merely illustrative, and for example, a division of a unit may be a logical division, and an actual implementation may have another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.