阅读说明：本技术 透镜组件、太赫兹波层析成像系统、方法及过滤器 (Lens assembly, terahertz wave tomography system, terahertz wave tomography method and filter ) 是由 王春雷 郭兰军 于 2018-08-07 设计创作，主要内容包括：本公开提供了一种透镜组件、太赫兹波层析成像系统、方法及过滤器。透镜组件包括：相对设置的第一基板和第二基板；密封件,与所述第一基板和所述第二基板围成腔体,所述腔体中填充有磁流体；和多个电磁产生单元,设置在所述第一基板靠近所述腔体的第一侧和远离所述腔体的第二侧中的至少一侧,其中,所述电磁产生单元在施加电压的情况下能够产生磁场,以使得所述磁流体形成菲涅尔波带片图案。(The disclosure provides a lens assembly, a terahertz wave tomography system, a terahertz wave tomography method and a filter. The lens assembly includes: the first substrate and the second substrate are oppositely arranged; the sealing element, the first substrate and the second substrate enclose a cavity, and magnetic fluid is filled in the cavity; and a plurality of electromagnetic generating units disposed on at least one of a first side of the first substrate close to the cavity and a second side of the first substrate far from the cavity, wherein the electromagnetic generating units are capable of generating a magnetic field under application of a voltage, so that the magnetic fluid forms a fresnel zone plate pattern.)

1. A lens assembly, comprising:

the first substrate and the second substrate are oppositely arranged;

the sealing element, the first substrate and the second substrate enclose a cavity, and magnetic fluid is filled in the cavity; and

a plurality of electromagnetic generation units disposed on at least one of a first side of the first substrate close to the cavity and a second side thereof far from the cavity, wherein the electromagnetic generation units are capable of generating a magnetic field under application of a voltage such that the magnetic fluid forms a Fresnel zone plate pattern.

2. The lens assembly of claim 1, said electromagnetic generation unit comprising a solenoid.

3. The lens assembly of claim 1, wherein projections of the plurality of electromagnetic generating units on a surface parallel to the surface of the first substrate are arranged in concentric circles or in a row-column matrix.

4. The lens assembly of claim 1, wherein at least one of the plurality of electromagnetic generating units is disposed on the first side;

the lens assembly further includes:

a first insulating layer disposed between the at least one electromagnetic generating unit and the magnetic fluid.

5. The lens assembly of claim 1, further comprising:

and the second insulating layer is arranged between the second substrate and the magnetic fluid.

6. The lens assembly of claim 1, at least one of the plurality of electromagnetic generating units being disposed on the second side;

the lens assembly further includes:

a protective layer covering the at least one electromagnetic generating unit.

7. The lens assembly of claim 1, wherein the plurality of electromagnetic generating units are symmetrically disposed with respect to the first substrate.

8. A terahertz wave tomography system comprising: the lens assembly of any one of claims 1-7, configured to receive terahertz waves and focus terahertz waves transmitted from the lens assembly at a position to be imaged of a sample to be imaged.

9. The imaging system of claim 8, further comprising:

a transmitter for transmitting a terahertz wave to the lens assembly;

and the processing device is used for receiving the terahertz waves transmitted from the sample to be imaged and processing the received terahertz waves to obtain an image of the position to be imaged.

10. A terahertz wave filter comprising: the lens assembly of any one of claims 1-7 and an aperture stop located at the light-emitting side of the lens assembly, wherein the lens assembly is configured to receive terahertz waves of different wavelengths and focus terahertz waves of a set wavelength at the aperture stop.

11. A terahertz wave tomography method comprising:

transmitting terahertz waves to the lens assembly of any one of claims 1-7;

applying a voltage to at least part of the plurality of electromagnetic generation units to enable the magnetic fluid to form a Fresnel zone plate pattern, so that the terahertz waves transmitted from the lens assembly are focused at a position to be imaged of a sample to be imaged; and

and receiving the terahertz waves transmitted from the sample to be imaged and processing the received terahertz waves to obtain an image of the position to be imaged.

12. The method of claim 11, wherein the electromagnetic generating units of the plurality of electromagnetic generating units to which a voltage is applied and the electromagnetic generating units to which no voltage is applied are distributed in a fresnel zone plate pattern.

13. The method of claim 11, wherein applying a voltage to at least some of the plurality of electromagnetic generation units to cause the magnetic fluid to form a fresnel zone plate pattern such that the terahertz waves transmitted from the lens assembly are focused at a location to be imaged of a sample to be imaged comprises:

applying a voltage to a first part of the plurality of electromagnetic generation units to enable the magnetic fluid to form a first Fresnel zone plate pattern, so that the terahertz waves transmitted from the lens assembly are focused at a first position to be imaged of a sample to be imaged;

applying a voltage to a second part of the plurality of electromagnetic generation units to enable the magnetic fluid to form a second Fresnel zone plate pattern, so that the terahertz waves transmitted from the lens assembly are focused at a second position to be imaged of the sample to be imaged;

wherein the second portion of electromagnetic generation units includes at least one electromagnetic generation unit different from the first portion of electromagnetic generation units such that a half-wave band radius of the second fresnel zone plate pattern is formed different from a half-wave band radius of the first fresnel zone plate pattern.

Technical Field

The disclosure relates to a lens assembly, a terahertz wave tomography system, a terahertz wave tomography method and a terahertz wave filter.

Background

With the development of terahertz technology, terahertz waves are widely used in various fields, such as biopsy, nondestructive detection, security inspection, and secure communication. In many application fields of terahertz waves, it is necessary to collect or focus terahertz waves.

Disclosure of Invention

The inventors have noted that the focal length of a lens for focusing terahertz waves in the related art is fixed, and such a lens cannot be applied to tomography.

In view of this, the disclosed embodiments provide a lens assembly with a variable focal length.

According to an aspect of embodiments of the present disclosure, there is provided a lens assembly including: the first substrate and the second substrate are oppositely arranged; the sealing element, the first substrate and the second substrate enclose a cavity, and magnetic fluid is filled in the cavity; and a plurality of electromagnetic generating units disposed on at least one of a first side of the first substrate close to the cavity and a second side of the first substrate far from the cavity, wherein the electromagnetic generating units are capable of generating a magnetic field under application of a voltage, so that the magnetic fluid forms a fresnel zone plate pattern.

In some embodiments, the electromagnetic generation unit comprises a solenoid.

In some embodiments, projections of the plurality of electromagnetic generating units on a surface parallel to the surface of the first substrate are arranged in concentric circles or in a row-column matrix.

In some embodiments, at least one of the plurality of electromagnetic generating units is disposed on the first side; the lens assembly further includes: a first insulating layer disposed between the at least one electromagnetic generating unit and the magnetic fluid.

In some embodiments, the lens assembly further comprises: and the second insulating layer is arranged between the second substrate and the magnetic fluid.

In some embodiments, at least one of the plurality of electromagnetic generating units is disposed on the second side; the lens assembly further includes: a protective layer covering the at least one electromagnetic generating unit.

In some embodiments, the plurality of electromagnetic generating units are symmetrically disposed with respect to the first substrate.

According to another aspect of the embodiments of the present disclosure, there is provided a terahertz wave tomography system including: the lens assembly according to any one of the above embodiments is configured to receive a terahertz wave and focus the terahertz wave transmitted from the lens assembly at a position to be imaged of a sample to be imaged.

In some embodiments, the imaging system further comprises: a transmitter for transmitting a terahertz wave to the lens assembly; and the processing device is used for receiving the terahertz waves transmitted from the sample to be imaged and processing the received terahertz waves to obtain an image of the position to be imaged.

According to still another aspect of the embodiments of the present disclosure, there is provided a terahertz wave filter including: the lens assembly and the aperture stop located on the light-emitting side of the lens assembly are used for receiving terahertz waves with different wavelengths and focusing the terahertz waves with set wavelengths at the aperture stop.

According to still another aspect of the embodiments of the present disclosure, there is provided a terahertz wave tomography method including: emitting terahertz waves to the lens assembly according to any one of the above embodiments; applying a voltage to at least part of the plurality of electromagnetic generation units to enable the magnetic fluid to form a Fresnel zone plate pattern, so that the terahertz waves transmitted from the lens assembly are focused at a position to be imaged of a sample to be imaged; and receiving the terahertz waves transmitted from the sample to be imaged and processing the received terahertz waves to obtain an image of the position to be imaged.

In some embodiments, the electromagnetic generating units with applied voltage and the electromagnetic generating units without applied voltage in the plurality of electromagnetic generating units are distributed in a fresnel zone plate pattern.

In some embodiments, applying a voltage to at least some of the plurality of electromagnetic generation units to cause the magnetic fluid to form a fresnel zone plate pattern such that the terahertz waves transmitted from the lens assembly are focused at a location to be imaged of a sample to be imaged comprises: applying a voltage to a first part of the plurality of electromagnetic generation units to enable the magnetic fluid to form a first Fresnel zone plate pattern, so that the terahertz waves transmitted from the lens assembly are focused at a first position to be imaged of a sample to be imaged; applying a voltage to a second part of the plurality of electromagnetic generation units to enable the magnetic fluid to form a second Fresnel zone plate pattern, so that the terahertz waves transmitted from the lens assembly are focused at a second position to be imaged of the sample to be imaged; wherein the second portion of electromagnetic generation units includes at least one electromagnetic generation unit different from the first portion of electromagnetic generation units such that a half-wave band radius of the second fresnel zone plate pattern is formed different from a half-wave band radius of the first fresnel zone plate pattern.

In the lens assembly provided by the embodiment of the disclosure, the electromagnetic generation unit can generate a magnetic field under the condition of applying voltage, so that the magnetic fluid forms a Fresnel zone plate pattern. The distribution of the magnetic fluid can be changed by controlling the applied voltage of the plurality of electromagnetic generating units, so that the half-wave band radius of a Fresnel zone plate pattern formed by the magnetic fluid is changed, and the focal length of the lens assembly can be changed. The focal length of such a lens assembly can be conveniently adjusted.

Other features, aspects, and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments thereof, which is to be read in connection with the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure, in which:

FIG. 1A is a schematic structural diagram of a lens assembly according to some embodiments of the present disclosure;

FIG. 1B is a schematic structural diagram of a lens assembly according to further embodiments of the present disclosure;

FIG. 1C is a schematic structural diagram of a lens assembly according to still further embodiments of the present disclosure.

FIG. 2A illustrates a schematic structural diagram of an electromagnetic generation unit, according to some embodiments of the present disclosure;

FIG. 2B illustrates an arrangement of a plurality of electromagnetic generating units according to some embodiments of the present disclosure;

FIG. 3A shows a schematic diagram of a Fresnel zone plate pattern;

FIG. 3B shows an imaging schematic of the lens assembly;

FIG. 4 is a schematic structural diagram of a lens assembly according to still further embodiments of the present disclosure;

FIG. 5 is a schematic structural diagram of a terahertz wave tomography system according to some embodiments of the present disclosure;

FIG. 6 is a schematic structural diagram of a terahertz wave tomography system according to further embodiments of the present disclosure;

FIG. 7 is a schematic structural diagram of a terahertz wave filter according to some embodiments of the present disclosure;

FIG. 8 is a schematic flow diagram of a terahertz wave tomography method according to some embodiments of the present disclosure;

FIG. 9 is a flow diagram of a method of manufacturing a lens assembly according to some embodiments of the present disclosure.

It should be understood that the dimensions of the various parts shown in the figures are not drawn to scale. Further, the same or similar reference numerals denote the same or similar components.

Detailed Description

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the disclosure, its application, or uses. The present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments are to be construed as merely illustrative, and not as limitative, unless specifically stated otherwise.

The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered. "upper", "lower", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

In the present disclosure, when a specific component is described as being located between a first component and a second component, there may or may not be intervening components between the specific component and the first component or the second component. When it is described that a specific component is connected to other components, the specific component may be directly connected to the other components without having an intervening component, or may be directly connected to the other components without having an intervening component.

All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

FIG. 1A is a schematic structural diagram of a lens assembly according to some embodiments of the present disclosure; FIG. 1B is a schematic structural diagram of a lens assembly according to further embodiments of the present disclosure; FIG. 1C is a schematic structural diagram of a lens assembly according to still further embodiments of the present disclosure.

As shown in fig. 1A, 1B and 1C, the lens assembly comprises a first substrate 101 and a second substrate 102 arranged opposite to each other. Here, the first substrate 101 and the second substrate 102 are spaced apart from each other. In some embodiments, the first substrate 101 and the second substrate 102 are glass substrates.

The lens assembly further includes a seal 103, such as a sealant or the like. The sealing member 103, the first substrate 101 and the second substrate 102 enclose a cavity 104, and a magnetic fluid 105 is filled in the cavity 104. In some embodiments, the magnetic fluid may include magnetic particles such as ferric oxide, ferroferric oxide, nickel, cobalt, and liquids such as water, organic solvents, oils, and the like. In certain embodiments, the magnetic fluid may also include an active agent such as oleic acid to prevent agglomeration of the magnetic particles.

In some embodiments, the cavity 104 may be a cylinder, such as a cylinder, prism, or the like. In this case, the sealing member 103 is a side surface of a pillar, and the first substrate 101 and the second substrate 102 are both bottom surfaces of the pillar. It is to be understood that the cavity 104 is not limited to a cylinder, and for example, the first substrate 101 and the second substrate 102 may be disposed non-parallel, so that the shape of the cavity 104 is irregular.

The lens assembly further comprises a plurality of electromagnetic generating units 106. The plurality of electromagnetic generating units 106 are disposed on at least one of a side (may also be referred to as a first side) of the first substrate 101 close to the cavity 104 and a side (may also be referred to as a second side) far from the cavity 104. The electromagnetic generation unit 106 can generate a magnetic field with a voltage applied thereto so that the magnetic fluid 105 forms a fresnel zone plate pattern.

In some embodiments, as shown in fig. 1A, all of the plurality of electromagnetic generating units 106 are disposed on a first side of the first substrate 101 near the cavity 104.

In other embodiments, as shown in fig. 1B, all of the plurality of electromagnetic generating units 106 are disposed on the second side of the first substrate 101 away from the cavity 104.

In still other embodiments, as shown in fig. 1C, some of the electromagnetic generating units 106 of the plurality of electromagnetic generating units 106 are disposed on a first side of the first substrate 101 close to the chamber 104, and other electromagnetic generating units 106 are disposed on a second side of the first substrate 101 away from the chamber 104.

In some implementations, at least one electromagnetic generating unit 106 of the plurality of electromagnetic generating units 106 is disposed at the second side, in which case the lens assembly may further include a protective layer, such as plastic or the like, at the second side and covering the electromagnetic generating unit 106 at the second side. The protective layer may protect the electromagnetic generating unit 106 disposed at the second side from an external environment, for example, from being oxidized, and the like.

In the above embodiments, the electromagnetic generating unit can generate a magnetic field under application of a voltage, so that the magnetic fluid forms a fresnel zone plate pattern. The distribution of the magnetic fluid can be changed by controlling the applied voltage of the plurality of electromagnetic generating units, so that the half-wave band radius of a Fresnel zone plate pattern formed by the magnetic fluid is changed, and the focal length of the lens assembly can be changed. The focal length of such a lens assembly can be conveniently adjusted.

Fig. 2A illustrates a schematic structural diagram of an electromagnetic generation unit, according to some embodiments of the present disclosure.

As shown in fig. 2A, the electromagnetic generating unit 106 may be a solenoid. The number of turns of the spiral of the solenoid may be, for example, one or more turns, and the shape of the coil in the solenoid may be circular, square, rectangular, or the like.

Fig. 2B illustrates an arrangement of a plurality of electromagnetic generating units 106, according to some embodiments of the present disclosure. Here, fig. 2B illustrates an arrangement of projections of the plurality of electromagnetic generating units 106 on a surface parallel to the surface of the first substrate 101, taking the electromagnetic generating units 106 as solenoids as an example.

As shown in fig. 2B, projections of the plurality of electromagnetic generating units 106 on the surface parallel to the surface of the first substrate 101 may be arranged in a matrix of rows and columns. It should be understood that such an arrangement is not a limitation of the present disclosure, for example, in other implementations, the projections of the plurality of electromagnetic generating units 106 on the surface parallel to the surface of the first substrate 101 may be arranged in other arrangements such as a concentric ring arrangement.

For example, a magnetic field for forming the magnetic fluid 106 into a fresnel zone plate pattern may be generated by controlling the applied voltages of the plurality of electromagnetic generating units 106. In some embodiments, a plurality of Thin Film Transistors (TFTs) may be disposed in the first substrate 101, and a voltage may be applied to the corresponding electromagnetic generating unit 106 via the TFTs. For example, taking the electromagnetic generating unit 106 as a solenoid, one end of the solenoid may be connected to the TFT (positive terminal +), and the other end of the solenoid may be connected to the ground (negative terminal-). In some embodiments, the solenoid may be disposed such that a magnetic field perpendicular to the first substrate 101 is generated when a voltage is applied thereto, for example, the solenoid may be disposed to spirally extend in a direction perpendicular to the first substrate 101. The magnetic field perpendicular to the first substrate 101 more easily controls the distribution of the magnetic fluid 105, thereby making the magnetic fluid forming the fresnel zone plate pattern more accurate.

In the case where no voltage is applied to the plurality of electromagnetic generating units 106, the magnetic fluid 106 is uniformly distributed in the cavity 105. In this case, the magnetic fluid 106 absorbs or reflects the terahertz waves, so that the terahertz waves cannot penetrate the cavity 104.

By controlling the applied voltages of the plurality of electromagnetic generating units 106, the electromagnetic generating units 106 to which voltages are applied and the electromagnetic generating units 106 to which voltages are not applied can be distributed in a fresnel zone plate pattern, that is, the circular rings of the electromagnetic generating units 106 to which voltages are applied and the circular rings of the electromagnetic generating units 106 to which voltages are not applied are concentrically staggered. In this case, the electromagnetic generating unit 106 to which the voltage is applied generates a magnetic field, and the magnetic fluid 106 is gathered above the electromagnetic generating unit 106 to which the voltage is applied by the magnetic field and is distributed in a substantially circular ring shape. A circular channel through which terahertz waves can pass is formed above the electromagnetic generating unit 106 to which no voltage is applied. In this way, the magnetic fluid 106 forms a fresnel zone plate pattern.

For example, the case where the voltages are applied to the plurality of electromagnetic generating units 106 disposed on the first side may be individually controlled so that the circular ring made up of the electromagnetic generating units 106 to which voltages are applied and the circular ring made up of the electromagnetic generating units 106 to which voltages are not applied among the electromagnetic generating units 106 located on the first side are distributed in a fresnel zone plate pattern.

For another example, the applied voltages of the plurality of electromagnetic generating units 106 disposed on the second side may be individually controlled such that a circular ring of electromagnetic generating units 106 with applied voltages and a circular ring of electromagnetic generating units 106 without applied voltages among the plurality of electromagnetic generating units 106 disposed on the second side are distributed in a fresnel zone plate pattern.

For another example, the voltages applied to the plurality of electromagnetic generating units 106 disposed on the first side and the second side may be controlled simultaneously, so that the circular ring formed by the electromagnetic generating units 106 applied with voltages in the electromagnetic generating units 106 disposed on the first side, the electromagnetic generating units 106 applied with voltages in the electromagnetic generating units 106 disposed on the second side, and the circular rings formed by the other electromagnetic generating units 106 not applied with voltages are distributed in a fresnel zone plate pattern.

The principle of changing the focal length of the lens assembly by changing the half-band radius of the fresnel zone plate pattern is described in detail below in conjunction with fig. 3A and 3B.

Fig. 3A shows a schematic diagram of a fresnel zone plate pattern.

As shown in fig. 3A, the black rings and the white rings are alternately arranged with the O as the center. It is noted that the middle white dot is merely to show the position of the center O. Here, the 1 st ring is a 1 st white ring closest to the center O, the 2 nd ring is a 1 st black ring adjacent to the 1 st white ring, and so on. Radius rho of the k-th half-wave band_kThe inner diameter of the kth ring is denoted by k, 1, 2, 3 ….

Fig. 3B shows an imaging schematic of the lens assembly.

In FIG. 3B, S is a point light source (e.g., a terahertz wave light source), R is an object distance (i.e., a distance between the point light source S and the lens element), and B is an image distance (i.e., a distance between the lens element and the imaging point P)₀Distance therebetween), ρ_kThe radius of the kth half-wave band.

The following equations (1) and (2) can be obtained from the optical principle of the fresnel zone plate:

equation (3) can be obtained from equations (1) and (2):

in the above equations (1), (2) and (3), λ is the wavelength of light emitted from the point light source S, and f is the focal length of the lens assembly.

From the formula (3), the focal length f and the radius ρ of the half-wave band_kAnd wavelength lambda. Under the condition of unchanging wavelength lambda, the radius rho of half-wave band can be adjusted_kTo adjust the focal length of the lens assembly. In addition, the radius ρ in the half-wave band_kInvariably, different wavelengths of light may be focused at different focal points.

In some implementations, the size of the electromagnetic generation unit 106 (e.g., the radius of the solenoid) may be set to be much smaller than the radius ρ of the half-wave band of the fresnel zone plate pattern formed by the electromagnetic generation unit 106 with voltage applied and the electromagnetic generation unit 106 without voltage applied_k. This may be such that the shape of the electromagnetic generating unit 106 does not have a large influence on the fresnel zone plate pattern.

In some embodiments, the plurality of electromagnetic generating units 106 may be symmetrically disposed at both sides of the first substrate 101.

In this case, the case where the plurality of electromagnetic generation units 106 located on the first side and the plurality of electromagnetic generation units 106 located on the second side apply voltages may be controlled simultaneously such that the ring made up of the electromagnetic generation units 106 to which voltages are applied and the ring made up of the electromagnetic generation units 106 to which voltages are not applied among the plurality of electromagnetic generation units 106 located on the first side are distributed in the first fresnel zone plate pattern, and the ring made up of the electromagnetic generation units 106 to which voltages are applied and the ring made up of the electromagnetic generation units 106 to which voltages are not applied among the plurality of electromagnetic generation units 106 located on the second side are distributed in the second fresnel zone plate pattern. Here, the second fresnel zone plate pattern and the first fresnel zone plate pattern are substantially the same. In this way, the magnetic field generated by the electromagnetic generating unit 106 on the first side to which the voltage is applied and the magnetic field generated by the electromagnetic generating unit 106 on the second side to which the voltage is applied will be superimposed, thereby enhancing the magnetic field strength to better control the distribution of the magnetic fluid 105.

In the above-described embodiment, the applied voltages of the plurality of electromagnetic generating units 106 provided on the first side or the second side may be controlled individually, or the applied voltages of the plurality of electromagnetic generating units 106 provided on the first side and the second side may be controlled simultaneously. In some cases, for example, in the case where the plurality of electromagnetic generation units 106 disposed on one of the first side and the second side do not normally operate, the case where the plurality of electromagnetic generation units 106 disposed on the other of the first side and the second side are applied with voltages may be individually controlled to generate a magnetic field that causes the magnetic fluid 105 to form a fresnel zone plate pattern. In this way, the reliability of the lens assembly may be improved.

FIG. 4 is a schematic structural diagram of a lens assembly according to still further embodiments of the present disclosure.

The lens assembly shown in fig. 4 differs from the lens assembly shown in fig. 1A in that it further comprises at least one of a first insulating layer 401 and a second insulating layer 402.

In some embodiments, referring to fig. 4, at least one electromagnetic generating unit 106 is disposed on a side of the first substrate 101 facing the cavity 104, i.e., a first side. In this case, the lens assembly may further comprise a first insulating layer 401, such as Polyimide (PI) or the like, arranged between the electromagnetic generating unit 106 and the magnetic fluid 105 at the first side. The first insulating layer 401 can ensure insulation between the magnetic fluid 105 and the electromagnetic generating unit 106 to avoid direct contact with the electromagnetic generating unit 106 in the case that the magnetic fluid 105 is a conductive magnetic fluid. In addition, it is also possible to prevent static electricity in the first substrate 101 from affecting the distribution of the magnetic fluid 105.

In some embodiments, referring to fig. 4, the lens assembly may further comprise a second insulating layer 402 disposed between the second substrate 102 and the magnetic fluid 105. The second insulating layer 402 can prevent static electricity in the second substrate 102 from affecting the distribution of the magnetic fluid 105.

In one or more embodiments, the lens assembly may include both the first insulating layer 401 and the second insulating layer 402. The first and second insulating layers 401, 402 may confine the magnetic field generated by the plurality of electromagnetic generating units 106 in the cavity 104 in order to better control the distribution of the magnetic fluid 105.

The lens assembly of each embodiment of the disclosure can be applied to the fields of, but not limited to, terahertz filtering, terahertz security check instruments, terahertz nondestructive imaging and the like.

The present disclosure also provides a terahertz wave tomography system, which may include the lens assembly of any one of the above embodiments. The lens assembly is used for receiving the terahertz waves and enabling the terahertz waves transmitted from the lens assembly to be focused at a position to be imaged of a sample to be imaged.

Some applications of the lens assembly are described below in connection with fig. 5-7.

Fig. 5 is a schematic structural diagram of a terahertz wave tomography system according to some embodiments of the present disclosure.

As shown in fig. 5, the imaging system comprises lens assembly 501, emitter 502 and processing means 503 of any of the embodiments described above.

Emitter 502 is used to emit terahertz waves to lens assembly 501.

Lens assembly 502 is configured to receive terahertz waves and focus the terahertz waves transmitted from lens assembly 502 at a location to be imaged (e.g., A, B, C, D or E) of sample 504 to be imaged.

The processing device 503 is configured to receive the terahertz wave transmitted from the sample 504 to be imaged and process the received terahertz wave to obtain an image of the position to be imaged. For example, an image of the position to be imaged may be obtained based on the intensity, phase, and the like of the terahertz wave transmitted from the sample to be imaged 504.

The working principle of the imaging system is described below.

The magnetic fluid 105 is caused to form a fresnel zone plate pattern by controlling the applied voltage conditions of the plurality of electromagnetic generation units 106 in the lens assembly 501. After the transmitter 502 transmits a terahertz wave with a certain fixed wavelength to the lens assembly 501, the terahertz wave transmitted through the magnetic fluid 105 is focused on a certain position to be imaged, such as a position a, of the sample 504 to be imaged. By changing the half-wave band radius of the fresnel zone plate pattern formed by the magnetic fluid 105 in the lens assembly 501, the focal length of the lens assembly 501 can be changed, so that the terahertz waves transmitted through the magnetic fluid 105 are focused at different positions of the sample 504 to be imaged, such as B, C, D or E. Here, A, B, C, D and E are located on the same straight line.

The terahertz waves can be focused at different positions of the sample 504 to be imaged along the same straight line according to the above manner. By adjusting the position of the sample 504 to be imaged, the terahertz waves can be focused at different positions of the sample 504 to be imaged along other straight lines, so that images of different positions to be imaged can be obtained, and tomography is also achieved.

In the imaging system of the embodiment, as the focal length of the lens assembly is variable, the terahertz waves can be focused at different positions of a sample to be imaged, so that images at different positions to be imaged can be obtained, and tomography is realized.

FIG. 6 is a schematic structural diagram of a terahertz wave tomography system according to further embodiments of the present disclosure.

As shown in fig. 6, the processing device 503 of the imaging system may include a collimating lens 513, a focusing lens 523, a receiver 533, and a processor 543.

The collimating lens 513 is used to collimate the terahertz waves transmitted from the sample 504 to be imaged. The focusing lens 523 is used to focus the collimated terahertz wave. The receiver 533 is configured to receive the focused terahertz wave. The processor 543 is configured to process the focused terahertz waves to obtain an image of a position to be imaged.

It should be noted that the processing device 503 is not limited to the specific implementation shown in fig. 6. For example, in some implementations, the processing device 503 may additionally include other components. Are not listed here.

Fig. 7 is a schematic structural diagram of a terahertz wave filter according to some embodiments of the present disclosure.

As shown in fig. 7, the terahertz wave filter includes a lens assembly 501 and an aperture stop 701 located on the light exit side of the lens assembly. The lens assembly 501 is used for receiving terahertz waves of different wavelengths and focusing the terahertz waves of a set wavelength at the aperture stop 701. In some embodiments, the terahertz wave filter may further include an emitter 502 for emitting terahertz waves of different wavelengths to the lens assembly 501.

For example, terahertz waves of different wavelengths are focused at different positions, such as A, B, C, D, E, after passing through lens assembly 501. The hole diaphragm 701 is arranged at the position E, so that terahertz waves (namely terahertz waves with preset wavelengths) at the position E can penetrate through the hole diaphragm 701, and terahertz waves at other positions cannot penetrate through the hole diaphragm 701, and filtering of the terahertz waves is achieved.

Fig. 8 is a schematic flow diagram of a terahertz wave tomography method according to some embodiments of the present disclosure.

At step 802, a terahertz wave is transmitted to the lens assembly of any of the above embodiments.

In step 804, voltages are applied to at least some of the plurality of electromagnetic generating units to make the magnetic fluid form a fresnel zone plate pattern, so that the terahertz waves transmitted from the lens assembly are focused at the position to be imaged of the sample to be imaged.

In some embodiments, the electromagnetic generating units to which a voltage is applied and the electromagnetic generating units to which no voltage is applied among the plurality of electromagnetic generating units are distributed in a fresnel zone plate pattern. Here, the electromagnetic generating unit to which the voltage is applied generates a magnetic field that causes the magnetic fluid in the lens assembly to form a fresnel zone plate pattern, thereby causing the magnetic fluid of the lens assembly to form a fresnel zone plate pattern.

In other embodiments, a plurality of electromagnetic generating units may be arranged in a fresnel zone plate pattern distribution. In this case, a voltage may be applied to all of the plurality of electromagnetic generating units to generate a magnetic field that causes the magnetic fluid in the lens assembly to form a fresnel zone plate pattern, thereby causing the magnetic fluid of the lens assembly to form a fresnel zone plate pattern.

At step 806, the transmitted terahertz waves from the sample to be imaged are received and processed to obtain an image of the location to be imaged.

In some implementations, the terahertz waves transmitted from the sample to be imaged can be processed according to the following manner: firstly, collimating terahertz waves transmitted from a sample to be imaged; then, focusing the collimated terahertz waves; and then, processing the focused terahertz waves to obtain an image of the position to be imaged.

In the above embodiment, the terahertz waves can be focused at different positions of the sample to be imaged by changing the focal length of the lens assembly, so that images at different positions to be imaged can be obtained, and tomographic imaging can be realized.

In some embodiments, step 804 in FIG. 8 may be implemented by:

applying voltage to a first part of the electromagnetic generation units in the plurality of electromagnetic generation units to enable the magnetic fluid to form a first Fresnel zone plate pattern, so that the terahertz waves transmitted from the lens assembly are focused at a first position to be imaged of the sample to be imaged; and

and applying voltage to a second part of the electromagnetic generation units in the plurality of electromagnetic generation units to enable the magnetic fluid to form a second Fresnel zone plate pattern, so that the terahertz waves transmitted from the lens assembly are focused at a second to-be-imaged position of the to-be-imaged sample.

Here, the second partial electromagnetic generating unit includes at least one electromagnetic generating unit different from the first partial electromagnetic generating unit, that is, the second partial electromagnetic generating unit is not identical to the first partial electromagnetic generating unit, so that a radius of a half-band of the second fresnel zone plate pattern formed is different from a radius of a half-band of the first fresnel zone plate pattern, thereby changing the second position to be imaged to be different from the first position to be imaged.

In this way, the position to be imaged can be changed, so that images of different positions to be imaged can be obtained.

FIG. 9 is a flow diagram of a method of manufacturing a lens assembly according to some embodiments of the present disclosure.

At step 902, a first substrate, a second substrate, and a seal are provided. Here, at least one side of the first substrate is provided with a plurality of electromagnetic generating units, such as solenoids.

In some embodiments, one side of the first substrate is provided with a plurality of electromagnetic generating units. In some embodiments, one side of the first substrate is further provided with a first insulating layer covering the plurality of electromagnetic generating units.

In other embodiments, both sides of the first substrate may be provided with a plurality of electromagnetic generating units, that is, one side of the first substrate may be provided with some of the plurality of electromagnetic generating units, and the other side of the first substrate may be provided with other electromagnetic generating units. In some embodiments, the plurality of electromagnetic generating units may be symmetrically disposed at both sides of the first substrate.

At step 904, a seal is disposed between the first substrate and the second substrate such that the seal, the first substrate, and the second substrate enclose a cavity.

For example, after the cavity is formed, an opening may be provided at a predetermined position of the cavity for subsequent injection of the magnetic fluid.

In some embodiments, one side of the second substrate may be provided with a second insulating layer. After the cavity is formed, the second insulating layer faces the first substrate.

At step 906, a magnetic fluid is injected into the cavity, thereby forming a lens assembly.

The method of manufacture shown in fig. 9 is merely exemplary, and those skilled in the art, given the teachings of this disclosure, may form lens assemblies in other ways as well. For example, a magnetic fluid may be dropped on one side of a first substrate having a plurality of electromagnetic generating units provided on one side thereof, a sealant may be applied on one side of a second substrate, and then the first substrate and the second substrate may be butted under vacuum to form a lens assembly.

Thus, various embodiments of the present disclosure have been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that various changes may be made in the above embodiments or equivalents may be substituted for elements thereof without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.