Monochromator based on liquid crystal PB lens

Abstract

The utility model discloses a monochromator based on a liquid crystal PB lens, which comprises a multi-stage liquid crystal PB lens module, an annular electrode liquid crystal optical switch module, a PB lens collimation module, a PB lens convergence module and an optical fiber coupling module. The PB lens collimation module is used for collimation, the PB lens convergence module is used for convergence, and finally, the PB lens is coupled and output through the optical fiber coupling module, the annular electrode liquid crystal optical switch module comprises a driving circuit, an annular electrode and a liquid crystal layer, and a voltage signal is applied to the liquid crystal layer of the annular electrode liquid crystal optical switch module to generate an electric field to change the refractive index of the liquid crystal layer. And light with a specific wavelength is annularly output through the annular electrode liquid crystal optical switch module. According to the utility model, not only are the spectral resolution and the flexibility of light path control improved, but also the miniaturization and integration of the system are realized, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to a monochromator, in particular to a monochromator based on a liquid crystal PB lens with high resolution and high flexibility. Background Technique

[0002] With the rapid development of optical technology, as an indispensable important device in optical experiments, the performance and application scope of the monochromator are constantly improving. The main function of the monochromator is to separate light of a single wavelength from a broadband light source, and it is widely used in fields such as spectral analysis, optical measurement, and optoelectronic device testing. Most traditional monochromators are based on mechanical scanning or grating dispersion principles, but these methods often have disadvantages such as complex structure, large volume, and slow response speed.

[0003] However, due to their characteristics such as being thin, light, easy to integrate, and electrically controllable tuning, liquid crystal optical elements show great application potential in the optical field. Especially the large dispersion characteristic of the liquid crystal PB (Pancharatnam-Berry) lens enables it to achieve wide-range dispersion of the spectrum within a short propagation distance. How to apply the liquid crystal PB lens to the monochromator is a research hotspot. Summary of the Utility Model

[0004] Purpose of the utility model: The purpose of the utility model is to provide a monochromator based on a liquid crystal PB lens with high resolution and high flexibility.

[0005] Technical solution: The utility model includes a multi-stage liquid crystal PB lens module, a ring electrode liquid crystal optical switch module, a PB lens collimation module, a PB lens focusing module, and an optical fiber coupling module. The light emitted by the light source is successively dispersed by the multi-stage liquid crystal PB lens module, filtered by the ring electrode liquid crystal optical switch module, collimated by the PB lens collimation module, focused by the PB lens focusing module, and finally coupled and output through the optical fiber coupling module. The ring electrode liquid crystal optical switch module includes a drive circuit, a ring electrode, and a liquid crystal layer. A voltage signal is applied to the liquid crystal layer of the ring electrode liquid crystal optical switch module to generate an electric field to change the refractive index of the liquid crystal layer, so that light of a specific wavelength is output in a ring shape through the ring electrode liquid crystal optical switch module.

[0006] Further, the multi-stage liquid crystal PB lens module is composed of a plurality of single-stage liquid crystal PB lenses cascaded, and is arranged in a stacked or side-by-side manner.

[0007] Further, the single-stage liquid crystal PB lens includes a liquid crystal layer and a PB lens.

[0008] Further, the ring electrode adopts a ring-shaped or approximately ring-shaped geometric shape.

[0009] Further, the ring electrodes are uniformly distributed on the liquid crystal layer to form a plurality of independent control regions.

[0010] Further, the annular electrode is made of ITO, i.e., indium tin oxide thin film.

[0011] Further, the drive circuit includes a voltage source, a signal generator, a voltage amplifier, and a feedback and regulation module, which are used to generate and output voltage signals.

[0012] Beneficial effects: Compared with the prior art, the present utility model has the following advantages: By introducing a multi-stage liquid crystal PB lens as a dispersion element and combining it with an annular electrode liquid crystal optical switch to achieve an annular light path output, the present utility model not only improves the spectral resolution and the flexibility of light path control, but also realizes the miniaturization and integration of the system, reduces costs; the use of the annular electrode liquid crystal optical switch improves the response speed of the optical switch; by adopting an optimized optical design, the reflection, scattering, and absorption of optical elements are reduced, the light loss is decreased, and the overall efficiency of the system is improved. Description of the Drawings

[0013] Figure 1 is a schematic structural diagram of the present utility model;

[0014] Figure 2 is a schematic structural diagram of the annular electrode liquid crystal optical switch module. Detailed Embodiments

[0015] The technical solution of the present utility model will be further described below with reference to the drawings.

[0016] As Figure 1 shown, the device of the present utility model includes a multi-stage liquid crystal PB lens module 1, an annular electrode liquid crystal optical switch module 2, a PB lens collimation module 3, a PB lens focusing module 4, and an optical fiber coupling module 5. The light emitted by the light source is sequentially dispersed by the multi-stage liquid crystal PB lens module 1, filtered by the annular electrode liquid crystal optical switch module 2, collimated by the PB lens collimation module 3, focused by the PB lens focusing module 4, and finally coupled and output through the optical fiber coupling module 5. The annular electrode liquid crystal optical switch module 2 includes a drive circuit, an annular electrode, and a liquid crystal layer. A voltage signal is applied to the liquid crystal layer of the annular electrode liquid crystal optical switch module 2 to generate an electric field to change the refractive index of the liquid crystal layer, so that light of a specific wavelength is output annularly through the annular electrode liquid crystal optical switch module 2.

[0017] Multi-stage liquid crystal PB lens module 1 (dispersion module): Immediately following the light source, it is composed of a plurality of cascaded liquid crystal PB lenses, which are used to disperse broadband light and disperse light of different wavelengths to different angles. The multi-stage design enhances the dispersion effect and improves the spectral resolution.

[0018] Ring - electrode liquid - crystal optical switch module 2: Located after the dispersion module, it controls the refractive - index change of the liquid - crystal layer through a ring - electrode, realizes the on - off control of light with a specific wavelength, and guides the selected monochromatic light to the ring - optical - path output.

[0019] PB - lens collimation module 3: Receives the monochromatic light output from the ring - electrode liquid - crystal optical switch, and uses the focusing and collimation characteristics of the PB lens to adjust the light beam into parallel light for subsequent processing.

[0020] PB - lens focusing module 4: Further focuses the collimated monochromatic light to improve the concentration and brightness of the light beam, preparing for subsequent fiber - optic coupling.

[0021] Fiber - optic coupling module 5: Efficiently couples the focused monochromatic light into an optical fiber for transmission to subsequent optical systems or detectors.

[0022] Specific application method of the multi - stage liquid - crystal PB - lens module 1 in a monochromator:

[0023] Light - source input: Wide - spectrum light emits from the light source and first enters the multi - stage liquid - crystal PB - lens system.

[0024] Dispersion process: When light passes through each stage of the PB lens, it is phase - modulated by the liquid - crystal layer. Lights with different wavelengths are dispersed to different spatial positions due to the refractive - index difference. As the light passes through more stages of the lens, the dispersion effect accumulates, and finally, efficient dispersion of the wide - spectrum light is achieved.

[0025] Dispersion - effect optimization: To optimize the dispersion effect, it can be achieved by adjusting the thickness and refractive index of the liquid - crystal layer and the parameters of the control signal (such as voltage amplitude, frequency, etc.). In addition, the dispersion performance can be further improved by optimizing the arrangement of the lenses and the distribution of the number of stages.

[0026] Subsequent processing: The dispersed light beam enters the ring - electrode liquid - crystal optical switch module. By precisely controlling the voltage distribution on the ring - electrode, the on - off control of light with a specific wavelength is realized, and it is guided into the ring - optical - path output. Subsequently, the light beam is processed by the PB - lens collimation and focusing modules, and finally, monochromatic light is output through the fiber - optic coupling module.

[0027] As Figure 2 shown, the ring - electrode liquid - crystal optical switch module 2 includes a drive circuit, a ring - electrode, and a liquid - crystal layer.

[0028] Layout of the ring - electrode

[0029] Geometric shape: The ring - electrode adopts a ring - shaped or approximately ring - shaped geometric shape to match the requirements of the optical switch for the ring - optical path. This layout helps to guide light with a specific wavelength to the ring - optical path while avoiding interference with light of other wavelengths.

[0030] Electrode distribution: The annular electrodes are evenly distributed on the liquid crystal layer, forming multiple independent control regions. Each control region corresponds to one or more specific wavelength ranges. By independently controlling the voltage signals of each region, precise selection of light with different wavelengths can be achieved.

[0031] Material selection: The annular electrodes are made of materials with good conductivity and high stability, such as ITO (indium tin oxide) thin films, etc. These materials not only have good conductivity but also can form good interfacial contact with the liquid crystal layer to ensure the effective transmission of voltage signals.

[0032] Design of the driving circuit

[0033] Voltage source: The driving circuit includes a stable voltage source for providing the voltage signals required to control the annular electrodes. The voltage source should have the characteristics of high precision and low noise to ensure the stability and reliability of the voltage signals.

[0034] Signal generator: The signal generator is used to generate control signals. This signal contains multiple voltage levels and timing information for precisely controlling the voltage changes of each control region on the annular electrodes. The signal generator can automatically adjust the parameters of the voltage signals according to the preset wavelength selection conditions.

[0035] Voltage amplifier: Since the liquid crystal layer has high requirements for voltage signals, a voltage amplifier is usually set after the signal generator to amplify the control signals to a voltage level sufficient to drive the annular electrodes. The voltage amplifier should have the characteristics of low distortion and high bandwidth to ensure the accurate transmission of voltage signals.

[0036] Feedback and regulation module: The driving circuit also includes a feedback and regulation mechanism for real-time monitoring of the refractive index change of the liquid crystal layer and the output state of the optical switch, and fine-tuning the voltage signals according to the monitoring results to achieve precise selection of monochromatic light and annular output.

[0037] Working principle:

[0038] When voltage signals are applied to the annular electrodes, an electric field will be generated in the liquid crystal layer. The action of the electric field will change the alignment direction of the liquid crystal molecules, thereby changing the refractive index of the liquid crystal layer. By precisely controlling the parameters of the voltage signals (such as voltage amplitude, frequency, waveform, etc.), precise adjustment of the refractive index of the liquid crystal layer can be achieved.

[0039] Monochromatic light selection: Since light with different wavelengths has different refractive indices in the liquid crystal layer, by adjusting the refractive index of the liquid crystal layer, light with specific wavelengths can be selectively allowed to pass through the optical switch and enter the annular optical path. At the same time, by adjusting the voltage signals of each control region on the annular electrodes, simultaneous selection or sequential selection of light with multiple wavelengths can be achieved.

[0040] Annular output: The precisely selected monochromatic light enters the annular optical path under the guidance of the annular electrode and realizes the annular output of the monochromatic light through subsequent optical processing (such as collimation, focusing, and fiber coupling by a PB lens). The liquid crystal material is selected as a liquid crystal material with high birefringence and good optoelectronic properties, such as cyanobiphenyl liquid crystals, to ensure the diffraction efficiency and stability of the grating. The grating period and thickness are precisely designed according to the target wavelength range and diffraction efficiency requirements. The period determines the wavelength interval of the diffracted light, while the thickness affects the diffraction efficiency and the optical path length. By applying an external electric field to control the alignment direction of the liquid crystal molecules, the polarization characteristics of the grating are changed, realizing the selective diffraction of light with different wavelengths.

[0041] The utility model improves the dispersion efficiency and accuracy: Utilizing the large dispersion characteristics of the multi-stage liquid crystal PB lens, more efficient and accurate spectral dispersion can be achieved, thus meeting the requirements of high-precision spectral analysis. The dispersion curve of the liquid crystal PB lens is smooth, capable of providing a wider wavelength selection range and higher wavelength selection accuracy;

[0042] Reduces the volume and weight: By adopting compact optical elements such as liquid crystal PB lenses and annular electrode liquid crystal optical switches, the monochromator of the present invention is smaller in volume and lighter in weight, facilitating portability and use in narrow spaces;

[0043] Improves the optical switch response speed: The annular electrode liquid crystal optical switch features fast response and can complete the optical path switching within an extremely short time, thus meeting the application requirements of high-speed spectral scanning and rapid wavelength switching;

[0044] Reduces the light loss: The monochromator of the present invention adopts an optimized optical design during the optical path conversion and coupling processes, reducing the reflection, scattering, and absorption of optical elements, thereby reducing the light loss and improving the overall efficiency of the system;

[0045] Reduces the cost: Due to the adoption of new optical elements such as liquid crystal PB lenses, the monochromator of the present invention reduces the manufacturing cost while maintaining high performance, which is conducive to large-scale promotion and application.

Claims

1. A monochromator based on a liquid crystal PB lens, characterized in that: It includes a multi-stage liquid crystal PB lens module (1), a ring electrode liquid crystal optical switch module (2), a PB lens collimation module (3), a PB lens focusing module (4), and an optical fiber coupling module (5). The light emitted by the light source is successively dispersed by the multi-stage liquid crystal PB lens module (1), filtered by the ring electrode liquid crystal optical switch module (2), collimated by the PB lens collimation module (3), focused by the PB lens focusing module (4), and finally coupled and output through the optical fiber coupling module (5). The ring electrode liquid crystal optical switch module (2) includes a driving circuit, a ring electrode, and a liquid crystal layer. A voltage signal is applied to the liquid crystal layer of the ring electrode liquid crystal optical switch module (2) to generate an electric field to change the refractive index of the liquid crystal layer, so that light of a specific wavelength is output in a ring shape through the ring electrode liquid crystal optical switch module (2).

2. The monochromator based on a liquid crystal PB lens according to claim 1, wherein: The multi-stage liquid crystal PB lens module (1) is formed by cascading a plurality of single-stage liquid crystal PB lenses, and is arranged in a stacked or side-by-side manner.

3. The monochromator based on a liquid crystal PB lens according to claim 2, characterized in that: The single-stage liquid crystal PB lens includes a liquid crystal layer and a PB lens.

4. The monochromator based on a liquid crystal PB lens according to claim 1, wherein: The ring electrode has a ring-shaped or approximately ring-shaped geometry.

5. The monochromator based on a liquid crystal PB lens according to claim 1, wherein: The ring electrodes are uniformly distributed on the liquid crystal layer to form a plurality of independent control regions.

6. The monochromator based on a liquid crystal PB lens according to claim 1, wherein: The ring electrode is made of ITO, that is, indium tin oxide thin film.

7. The monochromator based on a liquid crystal PB lens according to claim 1, wherein: The driving circuit includes a voltage source, a signal generator, a voltage amplifier, and a feedback and regulation module, and is used for generating and outputting a voltage signal.

Images