WO2020019573A1 - Narrow linewidth external cavity laser based on metasurface narrowband reflector - Google Patents

Abstract

Disclosed is a narrow linewidth external cavity laser based on a metasurface narrowband reflector, belonging to the field of lasers. The narrow linewidth external cavity laser comprises a gain medium (1), a collimating component (2) and a metasurface narrowband reflector (3), wherein a surface of the metasurface narrowband reflector is a metasurface of a sub-wavelength periodic structure, and the metasurface only reflects the light with target wavelengths and transmits the light with non-target wavelengths, thereby reducing a resonant bandwidth and realizing narrowband filtering. Signal light emitted by the gain medium is converted into parallel light by means of the collimating component and is perpendicularly incident on the metasurface; and a resonant cavity for only resonating and amplifying the light with the target wavelengths is composed of the metasurface and a reflection enhancement film on an outer side of the other end of the gain medium, and oscillates and amplifies laser light while selecting a wavelength of the laser light to finally create lasing, and the laser light is transmitted through the metasurface for being output. The external cavity laser has the advantages of a good wavelength stability, a high side-mode suppression ratio, a narrow linewidth, a great adjustment tolerance, and being manufactured by a simple process.

Description

Narrow linewidth external cavity laser based on metasurface narrowband mirror [Technical Field]

The invention belongs to the technical field of lasers, and more particularly, relates to a narrow line-width external cavity laser based on a super-surface narrow-band reflector.

【Background technique】

Since the advent of the first semiconductor laser in 1962, the semiconductor laser industry has developed rapidly in this half century. With the continuous improvement of output power and beam quality, semiconductor lasers have been widely used in many fields. Such as laser marking, spectrum research, amplifier, dense wavelength division multiplexing technology, solid-state laser pump source, etc. In addition, semiconductor lasers are also widely used in life fields such as indicators, bar code scanners, printers, and so on.

Semiconductor lasers have many unique advantages, such as small size, high photoelectric conversion efficiency, low driving power consumption, and wide coverage. However, there are also some serious shortcomings. For example, the line width is wide. Although some semiconductor lasers can reach about 10MHz, they are far from the ideal single-mode narrow linewidth (sub-kHz) requirements of many systems. External-cavity semiconductor lasers overcome the shortcomings of ordinary semiconductor lasers, such as wider line width and poor frequency stability. And it has high efficiency, long life, and stable frequency, and can be widely used in the fields of light wave device measurement, metrological detection, water quality detection, high-resolution spectral analysis, and so on. At present, the commonly used external cavity semiconductor lasers generally use grating combination, mainly fiber gratings, blazed gratings, volume Bragg gratings, etc., and their design principles are similar. By inserting a beam splitting element in the outer cavity, the beam splitting element and extra-cavity feedback mechanism are used to achieve the laser wavelength Tuning. The grating device itself is relatively sensitive to temperature and strain, which also causes the grating external cavity semiconductor laser made by the grating to be easily affected by the external environment, which leads to the instability of the external cavity system, and then affects the stability of the output laser. In addition, the semiconductor laser based on the grating structure requires complicated deposition and regrowth and high-precision lithography processes, and the overall manufacturing process is relatively complicated.

Therefore, it has become a technical problem in the field to solve the defects of complicated assembly process, low process tolerance, and sensitivity to environmental fluctuations of the traditional narrow-line-width external cavity laser.

[Summary of the Invention]

In view of the above defects or improvement needs of the prior art, the present invention provides a narrow linewidth external cavity laser based on a supersurface narrowband mirror, and the purpose thereof is to reflect a target wavelength by using a supersurface narrowband mirror and The wavelength is transmitted to reduce the resonant bandwidth and realize narrow-band filtering. The resonant cavity is composed of gain material and ultra-surface narrow-band mirror, thereby solving the technology of wide line width of external cavity laser, complex structure, sensitivity to environmental fluctuations, and poor stability. problem.

To achieve the above objective, the present invention provides the following technical solutions:

A narrow linewidth external cavity laser based on a metasurface narrowband mirror is characterized in that it includes a gain substance, a collimation component, and a metasurface narrowband mirror, where:

One end of the gain substance is a light emitting end for emitting signal light, and the signal light is collimated by the collimating component and becomes parallel light perpendicularly incident on a surface of the super-surface narrow-band reflector; The surface of the surface narrow-band mirror is a super-surface with a sub-wavelength periodic structure; the super-surface transmits and outputs non-target wavelengths, and reflects the target wavelength; the reflected target wavelength passes through the collimation component and the gain One end of the substance is incident to the outside of the other end of the gain substance; an antireflection coating is plated on the outside of the other end of the gain substance, which is used as a mirror to reflect the incident light again and is incident on the collimating component to the On the super-surface; in this way, a resonant cavity is formed by the other side of the gain material outside the antireflection film and the super-surface narrow-band mirror, and the gain material is used to repeatedly resonate and amplify the light of the target wavelength in combination with the gain material to finally form an excitation And the laser light is transmitted through the metasurface.

The signal light emitted by the gain material passes through the collimating component and is incident on the supersurface of the supersurface narrowband mirror vertically. The supersurface is a sub-wavelength periodic structure. For a sub-wavelength periodic structure, a vertically incident beam can excite a cluster of coherent oscillations of the light field inside the structure. The local oscillation of this light field interacts with the incident light and can change the transmission and reflection characteristics of the light. The signal light excites the coherent oscillation inside the metasurface, so that the metasurface narrowband mirror has a high reflectivity for the target wavelength that meets the internal oscillation conditions, a high transmittance for other non-target wavelengths, and reduces the bandwidth of the reflected light resonance. Reduce the bandwidth of the transmitted laser light after resonance to achieve narrow-band filtering; the transmitted wavelength is directly output, and the reflected target wavelength is incident on the other side of the gain material that is the gain material of the reflector; the ultra-surface narrow-band mirror and gain material The other side of the anti-reflection coating on the other side constitutes a resonant cavity. Combined with a gain substance, the laser wavelength is selected while it is continuously oscillated to amplify it. Finally, lasing is formed, and the lasing light is output through the supersurface.

Preferably, one or more spliced micro / nano graphic arrays are prepared on the super surface; the micro / nano graphic array is an array composed of a plurality of identical micro / nano graphic periodic arrangements; in this way, by adjusting the super surface The size and arrangement period of micro-nano patterns in a single micro-nano pattern array and the stitching of multiple micro-nano pattern arrays enable the supersurface to reflect only target wavelengths and transmit non-target wavelengths, reducing the bandwidth of resonance To achieve narrow-band filtering.

By adjusting the size and arrangement period of micro-nano patterns in a single micro-nano pattern array on the supersurface, and stitching multiple micro-nano pattern arrays, the super-surface narrow-band mirror has a high reflectivity for the target wavelength that meets the internal oscillation conditions. Other non-target wavelengths have high transmittance, and reduce the bandwidth of reflected light resonance, thereby reducing the bandwidth of laser light transmitted after resonance, and achieving narrow-band filtering.

By splicing one or more micro-nano pattern arrays with different reflection wavelengths on the super-surface structure, the super-surface narrow-band mirror can have high reflectivity for multiple wavelengths at the same time and high transmittance for other wavelengths. Implementation of a multi-wavelength external cavity laser. The laser wavelength output by the laser is determined by the target wavelength (Fano resonance) of the metasurface narrowband mirror.

Preferably, the above-mentioned narrow-line-width external cavity laser based on the super-surface narrow-band mirror further includes a second reflecting mirror that replaces the other side of the gain substance as the reflecting mirror, and the other side of the gain substance is plated outside An antireflection coating is not used as a reflector; the second reflector is disposed outside the other end of the gain substance; in this way, a resonant cavity is formed by the second reflector and the metasurface narrowband reflector , Repeatedly resonating and amplifying light of a target wavelength in combination with the gain substance, and finally forming lasing, the lasing light is output through the metasurface.

A second reflecting mirror is used as a reflecting mirror instead of the other side antireflection film on the other end of the gain material, and an alternative solution is given to make the present invention easier to implement.

Preferably, the reflectance of the anti-reflection film on the outside of the other end of the gain substance is adjusted, and the laser light is output through the other end of the gain substance and is not output through the hypersurface. The option of giving a laser light output makes the invention easier to implement.

Preferably, the bandwidth of the gain substance covers the resonance wave band of the ultra-surface narrowband mirror, and the reflected light can be amplified.

Preferably, the collimating component is a single collimating lens or a combination of a plurality of collimating lenses.

The collimation of the signal light by the collimation component improves the adjustment tolerance of the ultra-surface narrow-band mirror and further improves the stability of the laser output; the use of multiple collimating lenses to collimate the optical path further improves the light parallelism, and further improves The adjustment tolerance of the super-surface narrow-band mirror further improves the stability of the laser output; when the parallelism of the output beam of the gain substance is good, the collimation component can be appropriately simplified and flexibly adjusted.

Preferably, the micro-nano patterns in the micro-nano pattern array are arranged as a tetragonal lattice, a hexagonal lattice or a quasi-lattice.

Preferably, the micro / nano pattern is a nanopore, a nanopillar, a nanosphere, a nanoring or a nanorod. The above micro-nano graphics can be made by conventional processes, and the manufacturing process is simple.

In general, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

1. The super-surface narrow-band mirror and the other end of the gain material form a resonant cavity that only amplifies the target wavelength light. The laser wavelength is selected and it is continuously oscillated and amplified. Because the laser output wavelength is mainly by the super-surface narrow-band mirror. The reflection wavelength (Fano resonance wavelength) is determined, thereby improving the stability of the laser output; the use of collimation components to collimate the signal light improves the adjustment tolerance of the ultra-surface narrowband mirror and further improves the stability of the laser output ;

2. The present invention adjusts the size and arrangement period of micro-nano patterns in a single micro-nano pattern array on a super surface, and stitches multiple micro-nano pattern arrays, so that the super-surface reflects only target wavelengths and non-target wavelengths. Transmit, reduce the bandwidth of resonance, and realize narrow-band filtering. By adjusting the size and arrangement period of micro-nano patterns in the micro-nano pattern array and the stitching of multiple micro-nano pattern arrays, the reflection wavelength and method of the super-surface narrow-band mirror can be adjusted. The harmonic resonance quality factor and extinction ratio improve the stability of the laser output; the invention applies the wavelength selection characteristics of the super-surface narrow-band mirror to the external cavity laser, and the output wavelength of the laser is completely determined by the self-resonance wavelength of the super-surface and is not subject to resonance The effect of cavity length has the advantages of good wavelength stability, high side mode suppression ratio, narrow line width, large adjustment tolerance, and simple structure;

3. A second reflector is used instead of the outside of the other end of the gain material as a reflector, and the resonance of the target wavelength light is only amplified by one end of the gain material, the super-surface narrow-band reflector, the other end of the gain material, or the second reflector. Cavity, the laser wavelength is continuously selected and amplified while the wavelength of the laser is selected; different schemes make the invention simple in structure, simple in manufacturing process, and easier to implement;

4. Adjust the reflectance of the anti-reflection film on the other end of the gain material so that the laser light is output through the other end of the gain material and does not transmit through the supersurface; an alternative solution for the output of the laser light makes the invention Easier to implement

5. Use multiple collimating lenses to collimate the optical path, further improve the light parallelism, and then improve the adjustment tolerance of the super-surface narrow-band mirror, and further improve the stability of the laser output; when the parallelism of the output beam of the gain substance is good, The collimation system can be streamlined appropriately.

6. The micro-nano pattern is a nanopore, a nano-pillar, a nano-sphere, a nano-ring or a nano-rod, which can be produced by a conventional process, and the production process is simple.

[Brief Description of the Drawings]

FIG. 1 is a model of a narrow-line-width external cavity laser based on a metasurface mirror in Embodiment 1 of the present invention;

2 (a) is a schematic diagram of a supersurface structure in a preferred embodiment of the present invention;

2 (b) is a schematic diagram of a supersurface structure in a preferred embodiment of the present invention;

3 (a) is a model of a narrow-line-width external cavity laser based on a metasurface mirror in Embodiment 2 of the present invention;

Figure 3 (b) is a top view of the model of Figure 3 (a);

4 is a model of a narrow-line-width external cavity laser based on a metasurface mirror in Embodiment 3 of the present invention;

5 is a schematic diagram of a laser spectrum test in a preferred embodiment of the present invention;

6 is a test spectrum diagram of an external cavity laser in a preferred embodiment of the present invention;

FIG. 7 (a) is a first flowchart of making a supersurface according to a preferred embodiment of the present invention; FIG.

FIG. 7 (b) is a second flow chart of the method of making a supersurface in the preferred embodiment of the present invention; FIG.

FIG. 7 (c) is the third flowchart of making a supersurface in the preferred embodiment of the present invention; FIG.

FIG. 7 (d) is the fourth flowchart of the fabrication of the supersurface in the preferred embodiment of the present invention.

The same reference numbers are used throughout the drawings to refer to the same elements or structures, where:

1-gain chip 2-collimating lens 3-nano-surface narrow-band mirror

4-reflector 5-left collimator lens 6-right collimator lens

7-double-sided polished silicon substrate 8-silicon dioxide 9-silicon nitride

10-Photoresist

【detailed description】

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

Example 1

As shown in FIG. 1, the narrow-line-width external cavity laser in this embodiment includes a gain chip 1, a collimator lens 2, and a super-surface narrow-band reflector 3.

The gain chip 1 is a gain substance, and its adjustment power is convenient, and the two end faces a and b are easy to handle. The gain chip 1 is plated with an antireflection coating on the end face a to improve the light reflectance of the end face a, and an antireflection coating is plated on the end face b. Light transmittance. The bandwidth of the gain chip 1 covers the resonance band of the metasurface narrowband mirror 3.

A single collimating lens 2 is used as a collimating component for easy adjustment.

The surface of the metasurface narrowband mirror 3 is a subsurface of a sub-wavelength periodic structure, which has a high reflectivity to a target wavelength and transmits light of a non-target wavelength.

The broadband light emitted by the gain chip 1 exits from the b-end surface, collimated by the collimator lens 2, and becomes parallel light, which is incident on the metasurface of the metasurface narrowband mirror 3 vertically. The metasurface reflects the target wavelength and is not the target light. For transmission, the reflected light of the target wavelength passes through the collimator lens 2, the gain chip end face b, enters the gain chip 1, and is reflected again at the end face a. The resonance cavity is formed by the end face a and the super-surface narrowband mirror 3, and the gain chip is combined. 1 The target light is repeatedly amplified and amplified, and finally a lasing light is transmitted through the metasurface. In addition, by adjusting the end face a of the gain chip 1 to increase the reflectance of the reflective film, the end face a can also be used as a laser output end.

As a further preferred method, one or more spliced micro / nano graphic arrays are prepared on the super surface; the micro / nano graphic array is an array composed of a plurality of identical micro / nano graphic periodic arrangements; the micro / nano graphic refers to nanopores, nanopillars , Nanospheres, nanorings or nanorods, etc .; the micro / nano patterns in a micro / nano pattern array can be optionally arranged as a tetragonal lattice, a hexagonal lattice or a quasi-lattice. By adjusting the size and arrangement period of micro-nano patterns in a single micro-nano pattern array on the supersurface, and stitching multiple micro-nano pattern arrays, the super-surface reflects only the target wavelength, transmits non-target wavelengths, and reduces resonance Bandwidth to achieve narrow-band filtering.

The invention applies the resonance characteristics of the super-surface structure to an external cavity laser, firstly as a narrow-band reflector and secondly as a wavelength selector; by adjusting the super-surface structure and selecting a suitable figure of merit and extinction ratio, the output laser light is further improved. stability.

As shown in Fig. 2 (a) and Fig. 2 (b), there are schematic diagrams and schematic diagrams of the super-surface structure. In the figure, a micro-nano pattern array is prepared. When parallel light enters vertically, due to the cluster coherent oscillation of the micro / nano pattern array, this local oscillation will interact with the incident light to reflect the target wavelength, and non-target light will be transmitted out. The supersurface structure can optionally prepare one or more spliced micro / nano graphic arrays to achieve reflection and narrowband filtering of different target wavelengths.

Example 2

As shown in FIG. 3 (a), the narrow-line-width external cavity laser in this embodiment includes a gain chip 1, a mirror 4, and a super-surface narrow-band mirror 3, where:

The super-surface narrow-band mirror 3 is the same as that in Embodiment 1, and is not repeated here.

The gain chip 1 uses the gain chip in Embodiment 1. The difference is that the end face a of the gain chip 1 in this embodiment is coated with an anti-reflection coating instead of an anti-reflection coating to improve the light transmittance; the end face a is not used as a mirror. , The target wave band reflected by the super-surface narrow-band mirror 3 is not reflected, but is reflected by the mirror 4 instead.

The reflection wave band corresponding to the mirror 4 covers the target wave band reflected by the metasurface narrowband mirror 3.

The broadband light emitted by the gain chip 1 is emitted from the end face b, and the emitted light is incident on the metasurface narrowband mirror 3. Due to the cluster coherent oscillation of the micro-nano structure on the metasurface narrowband mirror 3, this local oscillation will be related to the incident light. The interaction reflects the target wavelength, and the non-target light is transmitted. The reflected target wavelength light passes through the end face b and the end face a of the gain chip 1 and is incident on the reflector 4 as shown in FIG. 3 (b). Here, The reflecting mirror 4 is perpendicular to the light emitted from the end face a of the gain chip 1, thereby forming a resonant cavity between the reflecting mirror 4, the gain chip 1, and the super-surface narrow-band mirror 3, of which only the perpendicular to the mirror and the super-surface narrow-band is formed. The light of the target wavelength of the reflector can be continuously amplified and amplified to form a laser, and the laser light is output from one end of the metasurface.

Example 3

As shown in FIG. 4, the narrow-line-width external cavity laser in this embodiment includes a gain chip 1, a left collimator lens 5, a right collimator lens 6, and a super-surface narrow-band mirror 3.

The processing of the super-surface narrow-band reflector 3, the gain chip 1, and its end faces a and b is the same as that in Embodiment 1, and details are not described herein again.

The left collimating lens 5 and the right collimating lens 6 are two collimating lenses, and a combination of them is used to form a collimating component. The light emitted from the gain chip 1 is collimated to become parallel light. At the same time, according to actual needs, the number of collimating lenses can be appropriately increased to improve the adjustment tolerance of the super-surface narrow-band mirror and further improve the stability of the laser output;

The broadband light emitted by the gain chip 1 exits from its end face b and is incident on the left collimating lens 5. The light passing through the left collimating lens 5 is converged on the left focal point of the right collimating lens 6. Thus, the light passes through the right collimating The lens 6 becomes parallel light; and because the double lens is used for collimation, the adjustment tolerance will increase, so the stability of the system will be improved; the parallel light emitted by the right collimator lens 6 will enter the hypersurface narrowband mirror 3 vertically. Due to the clustered coherent oscillation of the micro / nano structure on the hypersurface narrowband mirror 3, this local oscillation will interact with the incident light to reflect the target wavelength, the non-target wavelength will be transmitted out, and the reflected target wavelength The light passed through the right collimator lens 6, the left collimator lens 5, and the end face b of the gain chip 1, entered the gain chip 1, and finally reflected back at the end face a of the gain chip 1. Thus, the end face a of the gain chip 1 and the left A resonant cavity is formed between the collimating lens 5, the right collimating lens 6, and the metasurface. In combination with the gain chip 1, the target light is repeatedly amplified and amplified, and finally a lasing is formed. A gain chip 1 by the end face of the anti-reflection film, the end face may be used as a laser output.

Further, an embodiment of the present invention provides a laser output spectrum measurement system for measuring the spectral characteristics of the laser of the present invention.

As shown in Figure 5, the test system is mainly composed of a narrow linewidth external cavity laser, a focusing lens, a 3dB coupler, a spectrometer, and a power meter. Among them,

The narrow-line-width external-cavity laser uses the narrow-line-width external-cavity laser in Example 1; the focusing lens is used to collect the energy transmitted by the back of the super-surface narrow-band reflector 3 and input into the optical fiber. The role of the 3db coupler is to collect by the optical fiber The received energy is divided into two parts, which are respectively transmitted to the spectrometer and the power meter. The spectrometer is used to directly observe the spectral characteristics, and the power meter is used to detect the power of the output light.

When the test system is installed, first connect the 3dB coupler to the spectrometer and power meter, and then adjust the narrow-line-width external cavity laser to obtain the output laser. The adjustment sequence is:

1) Add current to the gain chip 1 and adjust it to around 100mA, then put the focusing lens, adjust the angle and height of the focusing lens, so that the power meter has the highest energy;

2) Put the collimator lens 2 and adjust the angle and height of the collimator lens 2 so that the power meter has the highest energy;

3) Put in a super-surface narrow-band mirror 3 and adjust the angle, mainly the adjustment of the Y and Z axes, while observing the spectrometer spectrum until the lasing of the target wavelength is observed.

After lasing, the threshold current and saturation current of the laser can be observed by adjusting the size of the current source; the stability of the laser output and the output power can be observed by a spectrometer and a power meter.

Figure 6 shows the results of the spectrum test, where the abscissa is the wavelength and the ordinate is the spectral energy. It can be seen that the extinction ratio is about 55dB and the quality factor is more than 10,000.

With the same principle, a slight adjustment of the test system can perform spectral measurement on the narrow linewidth external cavity laser of Examples 2-4.

Further, the embodiment of the present invention also provides a manufacturing process flow of a super-surface narrow-band reflector, which mainly uses Plasma Enhanced Chemical Vapor Deposition (PECVD) to deposit materials, and uses Electron Beam Lithography , EBL) exposure of the super-surface device, and finally through inductively coupled plasma etching equipment (ICP) etching to obtain the required super-surface structure, thereby obtaining a super-surface narrow-band mirror.

As shown in FIG. 7 (a), a double-sided polished silicon substrate 7 is used. First, PECVD is used to sequentially deposit 1.6 um of silicon dioxide (SiO ₂ ) 8 and 0.58 um of silicon nitride (Si ₃ N ₄ ) 9, wherein the SiO ₂ material is used as the isolation layer, and the Si ₃ N ₄ material is used as the functional layer.

As shown in FIG. 7 (b), after the substrate is cleaned and dried, a photoresist 10 (preferably a positive photoresist, such as ZEP-520) is spin-coated, and the photoresist is pre-baked. The exposed part of the glue will dissolve after development, and for a small area layout, the exposure time is reduced.

As shown in Figure 7 (c), the layout is transferred to the photoresist using EBL, and the exposure time is about 5-10min. After the exposure is completed, development and fixing are sequentially performed in xylene and isopropyl alcohol, and then the surface of the device is dried with a nitrogen gun after use. At this time, the exposed photoresist is dissolved, and the layout structure is transferred to the photoresist 10.

As shown in Figure 7 (d), ICP etching is used to remove part or all of the surface layer Si ₃ N ₄ that is not protected by the photoresist. The etching time is 27s, the etching depth is about 75nm, and the gas SF ₆ + C ₄ F is selected. ₈ . After that, the photoresist on the surface layer is removed by a degumming solution, and finally the device is rinsed with deionized water, and the device is dried by a nitrogen gun.

At this point, the fabrication of the super-surface narrow-band mirror is complete.

This paper proposes a narrow-band external-cavity laser based on a super-surface structure as a narrow-band mirror, which simultaneously selects the wavelength, which simplifies the manufacturing process and reduces the sensitivity of the laser to the external environment.

The present invention uses a super-surface narrow-band mirror as a narrow-band mirror and a wavelength selector. The super-surface narrow-band mirror and the other side of the gain material outside the anti-reflection film constitute a resonant cavity that only amplifies the target wavelength light. It continuously oscillates and amplifies it; the laser wavelength is mainly determined by the super-surface resonance wavelength, which improves the stability of the laser output; the use of collimation components to collimate the signal light increases the adjustment tolerance of the super-surface narrow-band mirror, and further improves The stability of the laser output is adjusted; by adjusting the supersurface structure to reflect only the target wavelength and transmit the non-target wavelength, reduce the bandwidth of resonance and achieve narrow-band filtering; it has good wavelength stability, high side mode suppression ratio, The advantages of narrow line width, large adjustment tolerance, and simple manufacturing process. In addition, the characteristics of the super-surface structure are applied to the fabrication of external cavity lasers, which provides a new idea for the application of the super-surface.

Those skilled in the art can easily understand that the above description is only the preferred embodiments of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention, All should be included in the protection scope of the present invention.

Claims (8)

1. A narrow linewidth external cavity laser based on a metasurface narrowband mirror is characterized in that it includes a gain substance, a collimation component, and a metasurface narrowband mirror, where:

   One end of the gain substance is a light emitting end for emitting signal light, and the signal light is collimated by the collimating component and becomes parallel light perpendicularly incident on a surface of the super-surface narrow-band reflector; The surface of the surface narrow-band mirror is a super-surface with a sub-wavelength periodic structure; the super-surface transmits and outputs non-target wavelengths, and reflects the target wavelength; the reflected target wavelength passes through the collimation component and the gain One end of the substance is incident to the outside of the other end of the gain substance; an antireflection coating is plated on the outside of the other end of the gain substance, which is used as a mirror to reflect the incident light again and is incident on the collimating component to the On the super-surface; in this way, a resonant cavity is formed by the other side of the gain material outside the antireflection film and the super-surface narrow-band mirror, and the gain material is used to repeatedly resonate and amplify the light of the target wavelength in combination with the gain material to finally form an excitation And the laser light is transmitted through the metasurface.
2. The narrow linewidth external cavity laser based on a hypersurface narrowband mirror according to claim 1, characterized in that one or more stitched micro / nano pattern arrays are prepared on the super surface; the micro / nano pattern array is Arrays formed by multiple identical micro / nano pattern cycles; in this way, by adjusting the size and arrangement cycle of micro / nano patterns in a single micro / nano pattern array on a supersurface, The metasurface only reflects the target wavelength and transmits the non-target wavelength, reducing the resonance bandwidth and achieving narrow-band filtering.
3. The narrow-line-width external cavity laser based on a super-surface narrow-band mirror according to claim 1, further comprising a second reflecting mirror that replaces the other side of the gain material as an external reflecting film, and The other end of the gain substance is plated with an antireflection coating and is not used as a mirror; the second reflector is disposed outside the other end of the gain substance; in this way, the second mirror and the The super-surface narrow-band mirror constitutes a resonant cavity, and repeatedly combines the gain substance with the target wavelength to repeatedly amplify the light at the target wavelength, and finally forms lasing, and the lasing light is output through the meta-surface.
4. The narrow linewidth external cavity laser based on a super-surface narrowband mirror according to claim 1, wherein the reflectance of the antireflection film on the outside of the other end of the gain substance is adjusted, and the lasing light passes through the gain substance. It is output at one end and does not output through the metasurface.
5. The narrow-line-width external-cavity laser based on a metasurface narrowband mirror according to any one of claims 1-4, wherein a bandwidth of the gain substance covers a resonance wave band of the metasurface narrowband mirror.
6. The narrow linewidth external cavity laser based on a super-surface narrowband mirror according to any one of claims 1 to 5, wherein the collimating component is a single collimating lens or a combination of a plurality of collimating lenses.
7. The narrow-line-width external cavity laser based on a hypersurface narrowband mirror according to claim 2, wherein the micro-nano patterns in the micro-nano pattern array are arranged in a tetragonal lattice, a hexagonal lattice, or a quasi-lattice. .
8. The narrow linewidth external cavity laser based on a super-surface narrowband mirror according to claim 2, wherein the micro / nano pattern is a nanopore, a nanocolumn, a nanosphere, a nanoring, or a nanorod.

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