A laser frequency selection module based on metasurface structure

Abstract

The present invention discloses a laser frequency selection module based on a metasurface structure, including a laser and a metasurface filter. When the wide-spectrum laser output by the laser passes through the metasurface filter, the metasurface filter has different transmittances for incident light of different wavelengths, thereby realizing filtering frequency selection. The present invention effectively reduces the system volume, improves the integration and anti-interference ability of the laser through the metasurface filter, and provides a new possibility for the development of high-power narrow-band lasers.

Description

Technical Field

[0001] The present invention belongs to the field of laser frequency selection and high-energy laser, and specifically relates to a laser frequency selection module based on a super surface structure. Background Art

[0002] At present, the production technology of lasers is relatively mature, but the most basic narrow-linewidth lasers are difficult to achieve high-power, low-loss pure line output. In the application scenarios of lasers, the lasers are mostly required to output single-longitudinal-mode beams with good monochromaticity. In order to narrow the output linewidth of the laser, the current methods for achieving narrow linewidth output mainly include external cavity compression method, optical narrowband filter method, saturated absorber method, polarization incoherence method, fiber scattering effect method, etc.

[0003] The external cavity compression method is mainly based on a high-stability ultra-narrow bandwidth reference cavity. However, the high-stability reference cavity is generally large in size and difficult to integrate with the laser, which is inconvenient in engineering implementation. The optical narrowband filter method is mainly based on the resonant cavity for mode selection, and the realization of the resonant cavity relies on a double FBG grating or a plane beam splitter to form an FP cavity to achieve the narrowband output of the light beam. This method has high requirements for the accuracy of the FP cavity, and currently only achieves a narrowband output of the kHz level. The saturated absorber method is generally used in fiber lasers. A saturated absorber is added to the optical fiber to produce a spatial hole burning effect. The remaining longitudinal modes outside the selected longitudinal mode are absorbed to achieve the purpose of single longitudinal mode output. However, this method has a limited range of longitudinal mode absorption and has a large power loss. The fiber scattering effect method is a narrowband follower filter based on Brillouin scattering and Rayleigh scattering. Currently, 2km of Rayleigh fiber can achieve a narrowband filtering effect of 10kHz.

[0004] The above narrowband filtering methods generally have the disadvantages of complex structure, large size, difficult to integrate, and unsatisfactory filtering effect. The size of the super-surface filter device based on micro-nano structure is small, and its filtering effect depends on the geometric parameters and processing accuracy of the designed micro-nano super-atomic structure, which can achieve a narrow line width output. Therefore, the application of super-surface filters in laser frequency selection modules is of great significance for the application of single longitudinal mode narrow line width high power lasers. Summary of the invention

[0005] The purpose of the present invention is to provide a laser frequency selection module based on a metasurface structure, which overcomes the defects of the prior art and solves the common shortcomings of narrow linewidth laser frequency selection modules, such as low energy utilization and redundant volume. The laser module relies on the phase intensity regulation of light beams of different wavelengths by a metasurface filter to achieve ultra-narrow linewidth laser filtering and frequency selection. Moreover, the linewidth of the laser can be further narrowed by configuring a Rayleigh fiber and a metasurface filter in combination. The present invention has the advantages of small size, simple structure, and high energy utilization efficiency, which is conducive to the further development of narrow linewidth lasers.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] A laser frequency selection module based on a metasurface structure comprises a laser and a metasurface filter. When the wide-spectrum laser output by the laser passes through the metasurface filter, the metasurface filter has different transmittances for incident light of different wavelengths, thereby realizing filtering and frequency selection.

[0008] Furthermore, the laser generated by the laser is irradiated to the metasurface filter to achieve filtering and frequency selection.

[0009] Furthermore, the laser is a laser with optical fiber output or spatial light output.

[0010] Furthermore, the laser generates a high-power laser beam by adding a pump source.

[0011] Furthermore, the laser adds Rayleigh fiber to perform preliminary high-efficiency narrowing on the generated laser to obtain multi-longitudinal mode narrow linewidth output, and then uses a metasurface filter to achieve laser longitudinal mode frequency selection to output single longitudinal mode narrow linewidth laser.

[0012] Furthermore, the Rayleigh optical fiber is an optical fiber that produces a stimulated Rayleigh scattering effect, thereby achieving laser line width narrowing without power loss.

[0013] Furthermore, the metasurface filter realizes single longitudinal mode filtering and frequency selection of the target wavelength by means of different transmittances of light in different wavelength bands.

[0014] Furthermore, the metasurface filter is configured as a reflective metasurface structure or a transmissive metasurface structure.

[0015] Furthermore, the metasurface filter is an array composed of superatomic structures, and filtering and frequency selection of different central wavelengths can be achieved by designing the geometric parameters of the superatomic structural units.

[0016] Beneficial effects of the present invention:

[0017] 1. The laser frequency selection module of the present invention innovatively uses a metasurface filter. The metasurface filter based on micro-nano super-atomic structural units has higher energy utilization, smaller size, narrower output line width and higher strong light tolerance compared to traditional filtering methods.

[0018] 2. The present invention innovatively combines Rayleigh fiber with a metasurface filter to obtain a narrower laser output linewidth and higher energy utilization. Its benefit lies in providing a new idea or method for the research and development of small-volume, narrow-linewidth, high-power lasers.

[0019] 3. The present invention can be widely used in the fields of laser frequency selection, high-energy laser, ultra-narrow laser, etc.

[0020] The aforementioned main scheme of the present invention and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection by the present invention; and in the present invention, (non-conflicting options) options and other options can also be freely combined. After understanding the scheme of the present invention, those skilled in the art can understand that there are many combinations based on the prior art and common knowledge, all of which are technical schemes to be protected by the present invention, and they are not exhaustively listed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 It is a schematic diagram of the microstructure of the supersurface filter of the present invention.

[0023] In the figure: 1-laser, 2-pump source, 3-Rayleigh fiber, 4-metasurface filter. DETAILED DESCRIPTION

[0024] The following non-limiting examples serve to illustrate the invention.

[0025] Embodiment 1:

[0026] refer to Figure 1 and Figure 2 As shown, a laser frequency selection module based on a metasurface structure includes a laser 1, a pump source 2, a Rayleigh fiber 3 and a metasurface filter 4.

[0027] The laser 1 is a laser including optical fiber output or spatial light output, and the laser output characteristics thereof mainly include wide spectrum and high coherence. When the wide spectrum laser output by the laser 1 is irradiated to the metasurface filter 4, the metasurface filter 4 has different transmittances for incident light of different wavelengths, thereby realizing filtering and frequency selection.

[0028] At the same time, the laser 1 generates a high-power laser beam by adding a pump source 2. Under the excitation of the pump source 2, the laser 1 generates a high-power laser with characteristics such as a wide spectrum and high coherence. This function can be selected according to actual needs.

[0029] Rayleigh fiber 3 is an optical fiber that produces stimulated Rayleigh scattering effect, which realizes laser line width narrowing without power loss. Laser 1 adds Rayleigh fiber 3, and stimulated Rayleigh scattering is generated when the laser beam passes through Rayleigh fiber 3, so that the output beam becomes a multi-longitudinal mode narrow line width laser beam, thereby performing preliminary high-efficiency narrowing on the generated laser to obtain multi-longitudinal mode narrow line width output, and then the laser longitudinal mode frequency selection is realized through the metasurface filter 4 to output a single longitudinal mode narrow line width laser. This function can be selected according to actual needs.

[0030] The metasurface filter 4 is configured as a reflective metasurface structure or a transmissive metasurface structure, which mainly realizes the function of narrowband filtering by adjusting the phase of light beams of different wavelengths. The metasurface filter 4 realizes single longitudinal mode filtering and frequency selection of the target wavelength by different transmittances of light beams of different wavelength bands.

[0031] refer to Figure 2 As shown, the metasurface filter 4 is an array composed of micro-nano super-atomic structures, the scale of the geometric parameters of the super-teleported substructures in the array is similar to its working wavelength, and the super-atomic structures therein have different transmittances to incident light of different wavelengths, thereby realizing the frequency-selective filtering of the metasurface. At the same time, its transmittance to incident light of different wavelengths is determined by its geometric parameters, so the design of its geometric parameters can realize filtering and frequency selection of different target wavelengths.

[0032] The above basic examples of the present invention and their further optional examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed for protection by the present invention. In the scheme of the present invention, each optional example can be arbitrarily combined with any other basic examples and optional examples.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser frequency selection module based on a metasurface structure, characterized in that: It comprises a laser (1) and a metasurface filter (4); when the wide-spectrum laser output by the laser (1) passes through the metasurface filter (4), the metasurface filter (4) has different transmittances for incident light of different wavelengths, thereby achieving filtering and frequency selection; The laser (1) adds a Rayleigh optical fiber (3) to initially narrow the generated laser with high efficiency to obtain a multi-longitudinal mode narrow linewidth output, and then uses a metasurface filter (4) to achieve laser longitudinal mode frequency selection to output a single longitudinal mode narrow linewidth laser; The laser light generated by the laser (1) is irradiated onto the metasurface filter (4) to achieve filtering and frequency selection; The laser (1) is a laser with optical fiber output or spatial light output; The laser (1) generates a high-power laser beam by adding a pump source (2); The Rayleigh optical fiber (3) is an optical fiber that produces a stimulated Rayleigh scattering effect, and achieves laser line width narrowing without power loss; The metasurface filter (4) realizes single longitudinal mode filtering and frequency selection of the target wavelength by means of different transmittances of light in different wavelength bands; The metasurface filter (4) is configured as a reflective metasurface structure or a transmissive metasurface structure; The metasurface filter (4) is an array composed of superatomic structures, and filtering and frequency selection of different central wavelengths can be achieved by designing the geometric parameters of the superatomic structural units.

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