Multi-mode laser optical frequency comb device and degenerate and degenerate multi-mode control method

Abstract

The invention provides a multi-mode laser optical frequency comb device and a degeneracy degeneration multi-mode control method. The device comprises a diamond crystal, an optical frequency sparse generation module and a degeneracy control module. According to the embodiment of the invention, based on the multi-mode laser optical frequency comb device, stress is applied to the diamond crystal and the lattice constant of the diamond crystal is regulated and controlled according to a degenerate and degenerate multi-mode control method, so that the degeneracy of Raman vibration is regulated and controlled, the optical frequency sparse mode is controlled, and the existing single-mode laser optical comb is regulated into the multi-mode laser optical comb for output; the multi-mode optical frequency comb formed by the single-mode optical frequency comb capable of generating a single mode or a plurality of spectral width intervals has the advantages of being wide in wavelength coverage range, large in spectral interval, capable of generating a plurality of spectral width intervals and tunable in spectral width interval.

Description

Technical Field

[0001] The present invention relates to the field of solid laser technology, and in particular to a multi-mode laser optical frequency comb device and a degenerate multi-mode control method. Background Art

[0002] Optical frequency combs play an important role in the fields of laser radar, optical atomic clocks, optical communications, and distance measurement. Existing optical frequency comb generation technologies mainly include mode-locked laser optical frequency combs based on ultrashort pulse technology, Kerr microcavity optical frequency combs, and electro-optical frequency combs. Limited by the complexity of the technology and the type of light source, the wavelength range of optical frequency combs is mostly concentrated at 1 μm, and there is only a single spectral width spacing, namely a single-mode optical frequency comb. For example, the maximum spectral width of the electro-optical frequency comb is 132 nm. This limits the application of optical frequency combs in special scenarios such as wide wavelength ranges and tunable spectral width spacing. Diamond crystals provide a new technical solution for optical frequency combs with their advantages of high thermal conductivity, large Raman frequency shift, and high gain coefficient. However, diamond crystals can only produce single-mode optical frequency combs under normal circumstances, and the spectral width spacing cannot be tuned. In summary, there is an urgent need for a multi-mode laser optical frequency comb device and a control method that meet the requirements of a wide wavelength coverage range, large spectral width spacing, multiple spectral width spacings and tunable spectral width spacing, so as to provide a feasible technical solution for the application of single-mode and multi-mode optical frequency combs with tunable spectral width spacing. Summary of the invention

[0003] The present invention provides a multi-mode laser optical frequency comb device and a degenerate multi-mode control method, which provides a new technical solution for optical frequency comb. It has the advantages of wide wavelength coverage, large spectral width spacing, multiple spectral width spacing and adjustable spectral width spacing, and can output single-mode or multi-mode laser optical frequency comb. It aims to solve the problems of existing optical frequency comb technology that there are few types of light sources, narrow wavelength coverage range, small spectral width spacing and only a single spectral width spacing.

[0004] The first aspect of the present invention provides a multi-mode laser optical frequency comb device, including a diamond crystal, an optical frequency comb generation module, and a degeneracy control module: The diamond crystal comprises two light-transmitting end faces arranged opposite to each other, and two stress-applying faces arranged opposite to each other in parallel; The degeneracy control module is used to adjust the lattice constant of the diamond crystal, thereby adjusting the degeneracy of the Raman vibration and controlling the mode of the optical frequency comb, and the degeneracy control module includes an analysis controller, a stress controller, and a degeneracy detector that are communicatively connected; The analysis controller is used to calculate the center frequency of the optical frequency comb obtained by exciting the diamond crystal and the theoretical applied stress value according to the setting parameters. , and generate the spectrum of the multi-mode laser optical frequency comb under theoretical conditions ; The stress controller comprises a stress shaping feedback sheet, a diamond anvil, a stress applicator, a detection ray transmitter coaxially arranged with the stress applying surface, and a ray feedback controller, which are sequentially arranged on both sides of the stress applying surface; the ray feedback controller receives the theoretical applied stress value signal, and transmits it to the stress applicator; the stress applicator converts the theoretical applied stress value The stress is applied to the diamond crystal through the diamond anvil and the stress shaping feedback plate; the detection ray transmitter emits detection rays and diffracts with the stress shaping feedback plate and the diamond crystal, and the ray detector feeds back the detected diffraction signal to the ray feedback controller and calculates the actual applied stress value. , the actual applied stress value The theoretical applied stress value The stress difference value , and according to the stress difference value Adjusting the magnitude of stress applied by the stress applicator; The degeneracy detector includes an excitation laser light source, a frequency detector and a spectrum analysis controller. The excitation laser light source excites the diamond crystal to generate the multi-mode laser light frequency comb and transmits it to the frequency detector; the frequency detector detects the spectrum of the multi-mode laser light frequency comb and transmits it to the spectrum analysis controller; the spectrum analysis controller analyzes and obtains the actual spectrum diagram , and transmits it to the analysis controller; the analysis controller analyzes the actual spectrum diagram Spectrum of multi-mode laser frequency comb under the theoretical conditions The difference in spectral width , and according to the spectral width spacing difference value , the stress deviation is calculated And feedback to the stress controller, according to the stress difference value Adjusting the magnitude of stress applied by the stress applicator; The optical frequency comb generation module is used to pump the stressed diamond crystal to generate a single-mode or multi-mode optical frequency comb, wherein the multi-mode optical frequency comb includes a plurality of single-mode optical frequency combs with spectral width intervals.

[0005] According to one embodiment of the present invention, a Raman resonant cavity mirror is included, wherein the Raman resonant cavity mirror includes a first Raman resonant cavity mirror and a second Raman resonant cavity mirror arranged on both sides of the light-transmitting end face of the diamond crystal, and the first Raman resonant cavity mirror and the second Raman resonant cavity mirror are coated cavity mirrors; or The two light-transmitting end faces of the diamond crystal are film-coated end faces.

[0006] According to one embodiment of the present invention, a beam shaping mirror is included to shape the pump laser beam and the optical frequency comb beam, and the beam shaping mirror is placed optically coaxially with the pump laser beam or the laser optical frequency comb.

[0007] According to one embodiment of the present invention, the degeneracy detector further includes a Raman enhanced cavity mirror, which includes a first Raman enhanced cavity mirror and a second Raman enhanced cavity mirror arranged on both sides of the light-transmitting end face of the diamond crystal, and the first Raman enhanced cavity mirror and the second Raman enhanced cavity mirror are coated cavity mirrors; or The two light-transmitting end faces of the diamond crystal are film-coated end faces.

[0008] According to one embodiment of the present invention, the theoretical applied stress value , Theoretical spectral width spacing , the crystal direction of stress action satisfies: in, , is the coordinate of the crystal direction in which stress acts, is the mass of the ith atom, which is m here. represents the Hamiltonian operator, is the vibration amplitude, is the equilibrium position of the atoms, For time, is the displacement of the atomic principle equilibrium position, is the nth spectral width spacing, n is the working degeneracy, n=1, 2, 3.

[0009] According to one embodiment of the present invention, the theoretical spectral width spacing The corresponding Raman activity intensity of the diamond crystal satisfy: in, is the linear polarizability Normal coordinates of Raman-active vibrational modes The derivative of .

[0010] According to an embodiment of the present invention, the multi-mode laser optical frequency comb includes one spectral width spacing or multiple spectral width spacings.

[0011] According to one embodiment of the present invention, the multi-mode laser optical frequency comb includes lasers of one frequency or multiple frequencies.

[0012] According to one embodiment of the present invention, the stress controller also includes a stress protection member, which is arranged between the two stress shaping feedback plates and located on the non-light-emitting surface on the side of the diamond crystal. The tensile fracture stress and the compressive fracture stress of the stress protection member are both weaker than those of the diamond crystal. The stress protection member is communicatively connected to the analysis controller. When the stress protection member is not broken, a positive correlation signal is transmitted to the analysis controller. When the stress protection member is broken, a negative correlation signal is transmitted to the analysis controller. When the analysis controller receives the negative correlation signal, the stress controller stops applying stress to the diamond crystal.

[0013] A second aspect of the present invention provides a degenerate multi-mode control method for a multi-mode laser optical frequency comb device as described above, wherein the degenerate multi-mode control method comprises: Step 1: Setting the parameters of the analysis controller, including the pump laser wavelength, theoretical spectral width spacing , stress action crystal direction, preset stress difference value, preset spectral width spacing difference value, working degeneracy n, the analysis controller calculates the center frequency of the excited optical frequency comb, the theoretical applied stress value according to the parameters , and generate the spectrum of the multi-mode laser optical frequency comb under theoretical conditions ; Step 2: applying stress to the diamond crystal, the analysis control 1 converts the theoretical applied stress value The ray feedback controller transmits the theoretical stress value to the stress applicator. Applying stress to the stress shaping feedback sheet and the diamond crystal through the diamond anvil; Step three, detecting the stress applied to the diamond crystal, the detection ray transmitter emits detection rays and diffracts with the stress shaping feedback sheet and the diamond crystal, the ray detector feeds back the detected diffraction ray signal to the ray feedback controller, the ray feedback controller screens and analyzes the diffraction ray signal, and calculates the actual applied stress value using the diffraction ray signal of the stress shaping feedback sheet , and analyze the actual applied stress value The theoretical applied stress value The stress difference value , and the stress difference value Transmit to the stress applicator, repeat step 2 and step 3 until the stress difference value Less than the preset stress difference value; Step 4: Detect and regulate the degeneracy of the diamond crystal. The excitation laser light source emits laser to excite the diamond crystal to generate an optical frequency comb. The frequency detector detects the spectrum of the multi-mode laser optical frequency comb and transmits it to the spectrum analysis controller. The spectrum analysis controller analyzes and obtains an actual spectrum diagram. , and transmits it to the analysis controller, which analyzes the actual spectrum diagram Spectrum of multi-mode laser frequency comb under the theoretical conditions The difference in spectral width The analysis controller is based on the spectral width spacing difference value , the stress deviation is calculated And transmitted to the stress controller, according to the stress difference value Adjust the stress applied by the stress applicator; repeat step 2, step 3, and step 4 until the spectral width spacing difference value is is smaller than the preset spectral width spacing difference value; Step five, generating a multi-mode optical frequency comb, the degeneracy detector stops working, the optical frequency comb generating module starts working, the pump laser light source emits a pump laser to pump the diamond crystal to generate a multi-mode laser optical frequency comb, the remaining part of the pump laser and the multi-mode laser optical frequency comb are transmitted to the optical comb detector, the optical comb detector analyzes and obtains the required actual spectrum diagram, and transmits it to the analysis controller to obtain the required actual spectrum diagram.

[0014] The present invention provides a multi-mode laser optical frequency comb device and a degenerate multi-mode control method, which is characterized by adopting a degeneracy control module to adjust the lattice constant of the diamond crystal, thereby adjusting the degeneracy of the Raman vibration and controlling the optical frequency comb mode. Then, the optical frequency comb generation module is used to adjust the existing single-mode laser optical comb into a single-mode or multi-mode laser optical frequency comb output with tunable spectral width spacing. Compared with the existing laser optical comb, the advantage is that a single-mode or multi-mode laser optical frequency comb with tunable spectral width spacing can be realized, and it has the advantages of a wide wavelength coverage range, a large spectral width spacing, and multiple spectral width spacings and tunable spectral width spacing. It solves the limitations of the existing laser optical frequency comb technology in tunable spectral width spacing, combined ranging of multiple optical frequency combs, narrow coverage wavelength range, and small spectral width spacing, and provides a new technical solution for the application of special scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 is a schematic structural diagram of a first multi-mode laser optical frequency comb device provided by an embodiment of the present invention; Figure 2 is a schematic structural diagram of a second multi-mode laser optical frequency comb device provided by an embodiment of the present invention; Figure 3 is a schematic structural diagram of a third multi-mode laser optical frequency comb device provided by an embodiment of the present invention; Figure 4 is a schematic structural diagram of a fourth multi-mode laser optical frequency comb device provided by an embodiment of the present invention; Figure 5 It is a schematic structural diagram of the fifth multi-mode laser optical frequency comb device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the following detailed description, many specific details are provided in order to provide a comprehensive understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present invention by illustrating examples of the present invention.

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] Figure 1 The first multi-mode laser frequency comb device provided by the embodiment of the present invention is a schematic diagram of the structure of the multi-mode laser frequency comb device. The multi-mode laser frequency comb device of the embodiment of the present invention comprises a diamond crystal 1 , an optical frequency comb generation module, and a degeneracy control module 3 .

[0021] The diamond crystal 1 includes two light-transmitting end faces 11 arranged opposite to each other, and two stress-applying surfaces 12 arranged opposite to each other in parallel. There is no limitation on the specific shape of the diamond crystal 1, and it may be, for example, a hexahedron, an octahedron or an irregular shape. When the diamond crystal is a hexahedron, the two light-transmitting end faces arranged opposite to each other are in a perpendicular relationship to the two stress-applying surfaces arranged opposite to each other in parallel. When the diamond crystal is an octahedron, the two light-transmitting end faces arranged opposite to each other are in an adjacent or spaced relationship to the two stress-applying surfaces arranged opposite to each other in parallel. When the diamond crystal is an irregular shape, the two light-transmitting end faces arranged opposite to each other and the two stress-applying surfaces arranged opposite to each other in parallel are different end faces.

[0022] The degeneracy control module 3 is used to adjust the lattice constant of the diamond crystal 1, thereby adjusting the degeneracy of the Raman vibration and controlling the mode of the multi-mode laser optical frequency comb. The degeneracy control module 3 includes an analysis controller 31, a stress controller, and a degeneracy detector 33 which are communicatively connected.

[0023] The analysis controller 31 is used to calculate the center frequency of the optical frequency comb obtained by exciting the diamond crystal 1 and the theoretical applied stress value according to the set parameters. , and generate the spectrum of the multi-mode laser optical frequency comb under theoretical conditions .

[0024] The stress controller includes a stress shaping feedback sheet, a diamond anvil, a stress applicator, which are sequentially arranged on both sides of the stress application surface, a detection ray transmitter and a ray feedback controller which are coaxially arranged with the stress application surface; the ray feedback controller 321 receives the theoretical applied stress value signal, and transmits it to the stress applicator 322; the stress applicator 322 converts the theoretical applied stress value The stress is applied to the diamond crystal 1 through the diamond anvil 323 and the stress shaping feedback plate 324; the detection ray transmitter 325 emits detection rays and reacts with the stress shaping feedback plate 324 and the diamond crystal 1 to cause diffraction, and the ray detector 326 feeds back the detected diffraction signal to the ray feedback controller 321 and calculates the actual applied stress value. , the actual applied stress value The theoretical applied stress value The stress difference value , and according to the stress difference value The magnitude of the stress applied by the stress applicator 322 is adjusted.

[0025] The degeneracy detector 33 includes an excitation laser light source 331, a frequency detector 332 and a spectrum analysis controller. The excitation laser light source 331 excites the diamond crystal 1 to generate the multi-mode laser light frequency comb and transmits it to the frequency detector 332; the frequency detector 332 detects the spectrum of the multi-mode laser light frequency comb and transmits it to the spectrum analysis controller; the spectrum analysis controller analyzes and obtains the actual spectrum diagram , and transmits it to the analysis controller 31; the analysis controller 31 analyzes the actual spectrum diagram Spectrum of multi-mode laser frequency comb under the theoretical conditions The difference in spectral width , and according to the spectral width spacing difference value , the stress deviation is calculated And feedback to the stress controller, according to the stress difference value The magnitude of the stress applied by the stress applicator 322 is adjusted.

[0026] After the stress applied to the diamond crystal 1 is adjusted by the degeneracy control module 3 to adjust the lattice constant of the diamond crystal 1, the optical frequency comb generation module pumps the diamond crystal 1 to output a single-mode or multi-mode optical frequency comb, wherein the multi-mode optical frequency comb may include a single-mode optical frequency comb with multiple spectral width intervals.

[0027] In some embodiments, a pump laser light source pumps the diamond crystal 1 with a pump laser to generate a laser optical frequency comb, which can be measured by transmitting it to an optical frequency comb detector.

[0028] The multi-mode laser optical frequency comb device provided by the present invention applies stress to the diamond crystal 1 through the degeneracy control module 3, so that the triple degenerate Raman vibration mode of the diamond crystal 1 is degenerated, and a single-mode or multi-mode optical frequency comb can be generated, and the spectral width spacing of the optical frequency comb can be adjusted by controlling the magnitude of the applied stress and the crystal direction of the stress application. The multi-mode laser optical frequency comb device of this embodiment can output a single-mode or multi-mode optical frequency comb with the advantages of a wide wavelength coverage range, a large spectral width spacing, multiple spectral width spacings, and tunable spectral width spacings. A feasible technical solution is provided for the application of single-mode and multi-mode optical frequency combs with tunable spectral width spacings.

[0029] In some embodiments, see Figure 2As shown, the multi-mode laser optical frequency comb device may further include a Raman resonant cavity mirror 222, wherein the Raman resonant cavity mirror 222 includes a first Raman resonant cavity mirror 2221 and a second Raman resonant cavity mirror 2222 arranged on both sides of the light-transmitting end face 11 of the diamond crystal 1, wherein the first Raman resonant cavity mirror 2221 and the second Raman resonant cavity mirror 2222 may be coated mirrors, wherein the first Raman resonant cavity mirror 2221 has high transmittance to the pump laser and high reflection to the multi-mode laser optical frequency comb, and the second Raman resonant cavity mirror 2222 has high reflection to the pump laser and partial reflection to the multi-mode laser optical frequency comb, so as to reduce the output threshold of the multi-mode laser optical frequency comb and improve the conversion efficiency.

[0030] In other embodiments, the two light-transmitting end faces 11 of the diamond crystal 1 can be directly coated, the pump laser input coating end face has high transmittance to the pump laser and high reflection to the multi-mode laser frequency comb, and the multi-mode laser frequency comb output coating end face has high reflection to the pump laser and partial reflection to the multi-mode laser frequency comb. Directly coating the end face of the diamond crystal 1 can reduce the output threshold of the multi-mode laser frequency comb, improve the conversion efficiency, and improve the beam quality.

[0031] In some implementations, see Figure 2 As shown, the multi-mode laser optical frequency comb device may also include an optically coaxially placed beam shaping mirror 221 for beam shaping the pump laser or the laser optical frequency comb to meet applicable requirements. The beam shaping mirror 221 may include a lens, a half glass, and a polarizer to optimize and control the spot radius, divergence angle, and polarization state of the pump laser or the laser optical frequency comb.

[0032] In some embodiments, see Figure 2 As shown, the degeneracy detector 33 may also include a Raman enhanced cavity mirror 334, which includes a first Raman enhanced cavity mirror 3341 and a second Raman enhanced cavity mirror 3342 arranged on both sides of the light-transmitting end face 11 of the diamond crystal 1, and the first Raman enhanced cavity mirror 3341 and the second Raman enhanced cavity mirror 3342 may be coated cavity mirrors, wherein the first Raman enhanced cavity mirror 3341 has high transmittance to the excitation laser and high reflection to the detection multi-mode laser optical frequency comb, and the second Raman enhanced cavity mirror 3342 has high reflection to the excitation laser and partial reflection to the detection multi-mode laser optical frequency comb, so as to reduce the threshold of the detection multi-mode laser optical frequency comb output and improve the conversion efficiency. In another embodiment, the two light-transmitting end faces of the diamond crystal 1 are coated end faces, the coated end face for the excitation laser input has high transmittance to the excitation laser and high reflection to the detection multi-mode laser optical frequency comb, and the output end face for the detection multi-mode laser optical frequency comb has high reflection to the excitation laser and partial reflection to the detection multi-mode laser optical frequency comb.

[0033] In some embodiments, continue to refer to Figure 1 and Figure 2As shown, the theoretical applied stress value , Theoretical spectral width spacing , the crystal direction of stress action satisfies: (1) in, , is the coordinate of the crystal direction in which stress acts, is the mass of the ith atom, which is m here. represents the Hamiltonian operator, is the vibration amplitude, is the equilibrium position of the atoms, For time, is the displacement of the atomic principle equilibrium position, is the nth spectral width spacing, where n=1, 2, 3, and is the spectral width spacing of multi-mode optical frequency sparseness. The relationship between the theoretical spectral width spacing and the theoretical applied stress value is optimized and adjusted through the formula to achieve the purpose of selecting the appropriate crystal orientation and stress according to the spectral width spacing required for use.

[0034] In some embodiments, continue to refer to Figure 1 and Figure 2 As shown, the theoretical spectral width spacing Corresponding to the Raman activity intensity of diamond crystal satisfy: (2) (3) (4) in, is the linear polarizability Normal coordinates of Raman-active vibrational modes The derivative of the theoretical spectral width is When it is 0, the single-mode optical frequency comb with this theoretical spectral width does not exist, and the Raman activity intensity When it is not 0, a single-mode optical frequency comb with this theoretical spectral width spacing exists in the multi-mode optical frequency comb.

[0035] In some embodiments, the lattice of the diamond crystal can be adjusted by the degeneracy control module to achieve an optical frequency comb output with one spectral width spacing or multiple spectral width spacings according to actual needs. The output optical frequency comb may include one frequency or multiple frequency lasers.

[0036] In some embodiments, see Figure 3As shown, the stress controller may also include a stress protection member, which is arranged between the two stress shaping feedback plates 324 and located on the non-light-emitting surface on the side of the diamond crystal 1. The tensile fracture stress and compressive fracture stress of the stress protection member are both weaker than the maximum tensile fracture and compressive fracture stress of the diamond crystal 1. The stress protection member is communicatively connected with the analysis controller 31. When the stress protection member is not broken, it is an insulator and cannot transmit electrical signals, and transmits positive correlation signals to the analysis controller 31. When the stress protection member is broken, it suddenly becomes a conductor and can transmit electrical signals, and transmits negative correlation signals to the analysis controller 31. When the analysis controller 31 receives the negative correlation signal, the stress controller stops applying stress to the diamond crystal 1.

[0037] In some embodiments, see Figure 4 As shown, the optical frequency comb generation module includes multiple wavelength pump laser light sources, which pump diamond crystals to generate multiple optical frequency combs in different wavelength ranges to meet the demand for multi-wavelength laser optical frequency comb output when the optical frequency combs have the same spectral width spacing.

[0038] The present invention also provides a degenerate multi-mode control method, which comprises: Step 1: Set the parameters of the analysis controller 31, including the pump laser wavelength, theoretical spectral width spacing, , stress action crystal direction, preset stress difference value, preset spectral width spacing difference value, working degeneracy n, the analysis controller 31 calculates the center frequency of the excited optical frequency comb, the theoretical applied stress value according to the parameters , and generate the spectrum of the multi-mode laser optical frequency comb under theoretical conditions ; Step 2: applying stress to the diamond crystal, and the analysis controller 31 converts the theoretical applied stress value The ray feedback controller 321 transmits the theoretical stress value to the stress applicator 322. The stress is applied to the stress shaping feedback piece 324 and the diamond crystal 1 through the diamond anvil 323; Step three, detect the stress applied to the diamond crystal, the detection ray transmitter 325 emits detection rays and reacts with the stress shaping feedback plate 324 and the diamond crystal 1 to cause diffraction, the ray detector 326 feeds back the detected diffraction ray signal to the ray feedback controller 321, the ray feedback controller 321 screens and analyzes the diffraction ray signal, and uses the diffraction ray signal of the stress shaping feedback plate 324 to calculate the actual applied stress value , and analyze the actual applied stress value The theoretical applied stress value The stress difference value , and the stress difference value Transmitted to the stress applicator 322, repeating step 2 and step 3 until the stress difference value Less than the preset stress difference value; Step 4: Detect and regulate the degeneracy of the diamond crystal. The excitation laser light source 331 emits laser to excite the diamond crystal 1 to generate a multi-mode laser optical frequency comb. The frequency detector 332 detects the spectrum of the multi-mode laser optical frequency comb and transmits it to the spectrum analysis controller. The spectrum analysis controller analyzes and obtains the actual spectrum diagram. , and transmitted to the analysis controller 31, the analysis controller 31 analyzes the actual spectrum diagram Spectrum of multi-mode laser frequency comb under the theoretical conditions The difference in spectral width The analysis controller 31 is based on the spectral width spacing difference value , the stress deviation is calculated And transmitted to the stress controller, according to the stress difference value Adjust the stress applied by the stress applicator 322; repeat step 2, step 3, and step 4 until the spectral width spacing difference value is is smaller than the preset spectral width spacing difference value; Step five, generate a multi-mode optical frequency comb, the degeneracy detector 33 stops working, the optical frequency comb generating module starts working, the pump laser light source emits a pump laser to pump the diamond crystal 1 to generate a multi-mode laser optical frequency comb, the remaining part of the pump laser and the multi-mode laser optical frequency comb are transmitted to the optical comb detector 23, the optical comb detector 23 analyzes and obtains the required actual spectrum diagram, and transmits it to the analysis controller 31 to obtain the required actual spectrum diagram.

[0039] The degenerate multi-mode control method of this embodiment applies stress to the diamond crystal 1 through the degeneracy control module 3, so that the triple degenerate Raman vibration mode of the diamond crystal 1 is degenerated, and the mode of the optical frequency comb is regulated, so that the diamond crystal has the ability to generate a single-mode or multi-mode optical frequency comb. The spectral width spacing of the optical frequency comb can be adjusted by controlling the magnitude of the applied stress and the crystal direction of the stress application. And according to actual needs, an optical frequency comb output with one spectral width spacing or multiple spectral width spacing can be achieved, and the optical frequency comb can include one frequency or multiple frequency lasers. The single-mode or multi-mode optical frequency comb output by the multi-degenerate multi-mode control method of this embodiment has the advantages of a wide wavelength coverage range, a large spectral width spacing, multiple spectral width spacings, and tunable spectral width spacing. Provide a feasible technical solution for the application of single-mode and multi-mode optical frequency combs with tunable spectral width spacing.

[0040] The multi-mode laser optical frequency comb device and the degenerate multi-mode control method of the present invention are described in detail below based on specific embodiments.

[0041] Example 1 The first multi-mode laser frequency comb device provided in this embodiment is shown in Figure 1 As shown, it includes a diamond crystal 1, a set of optical frequency sparseness generating modules, and a set of degeneracy control modules 3.

[0042] Diamond crystal 1 is 2*2*7mm 3 The standard Raman frequency shift of a six-sided cuboid is 1332.5 cm -1 , used to generate and output multi-mode laser frequency combs, two of which are opposite to each other and have a 2*2mm 2 Surface 11 is the light-transmitting surface, and two relatively parallel 2*7mm 2 The surface 12 is a stress-applying surface.

[0043] An optical frequency comb generation module is used to pump the diamond crystal 1 to generate the multi-mode laser optical frequency comb, including a pump laser light source and an optical frequency comb detector which are optically coaxially placed in sequence; the pump laser emitted by the pump laser light source is a femtosecond laser with a central wavelength of 532 nm, a pulse width of 100 fs, a repetition rate of 1 KHz, an average power of 1 mW, and linearly polarized light.

[0044] The degeneracy control module 3 is used to adjust the lattice constant of the diamond crystal 1, thereby adjusting the degeneracy of the Raman vibration and controlling the mode of the multi-mode laser optical frequency comb, and includes a communication-connected analysis controller 31, a stress controller, and a degeneracy detector 33; the degeneracy control module 3 relies on a degenerate multi-mode control method.

[0045] The multi-mode laser frequency comb device provided in this embodiment has the following adjustment process: Set the parameters of the analysis controller 31, the pump laser wavelength is 532 nm, the stress action crystal direction is

[100] crystal direction, the working degeneracy n=2, and the theoretical spectrum width spacing is set 1385 cm -1 、1354 cm -1 , the preset stress difference value is ±0.2GPa, and the preset spectral width spacing difference value is 1%. The analysis controller 31 calculates the center frequencies of the excited optical frequency combs as 574.3 nm and 573.3 nm according to the parameters. Calculation, theoretical applied stress value The temperature is 47.7 GPa, and the spectrum of the multi-mode laser frequency comb described in the theoretical conditions is generated. 463.7 nm, 495.5 nm, 532 nm, 574.3 nm, 624 nm, 465 nm, 496.3 nm, 532 nm, 573.3 nm, 621.5 nm; Stress is applied to the diamond crystal, and the analysis controller 31 converts the theoretical applied stress value The ray feedback controller 321 transmits the theoretical stress value to the stress applicator 322. The stress is applied to the stress shaping feedback piece 324 and the diamond crystal 1 through the diamond anvil 323; The stress applied to the diamond crystal is detected. The detection ray transmitter 325 emits detection rays and reacts with the stress shaping feedback plate 324 and the diamond crystal 1 to cause diffraction. The ray detector 326 feeds back the detected diffraction ray signal to the ray feedback controller 321. The ray feedback controller 321 screens and analyzes the diffraction ray signal and calculates the actual applied stress value using the diffraction ray signal of the stress shaping feedback plate 324. The actual applied stress value is 40 GPa. The theoretical applied stress value The stress difference value The value is 7.7 GPa, which is greater than the preset stress difference value of 0.2 GPa. Repeat steps 2 and 3 to calculate the actual applied stress value. It is 47.6 GPa, which is less than the preset stress difference value of 0.2 GPa.

[0046] To detect and regulate the degeneracy of the diamond crystal, the excitation laser light source 331 emits laser to excite the diamond crystal 1 to generate a multi-mode laser optical frequency comb, and the frequency detector 332 detects the spectral width of the multi-mode laser optical frequency comb to be 1385 cm -1 、1354 cm -1 , and transmit it to the spectrum analysis controller; the spectrum analysis controller analyzes and obtains the actual spectrum diagram , and transmitted to the analysis controller 31, the analysis controller 31 analyzes the actual spectrum diagram Spectrum of multi-mode laser frequency comb under the theoretical conditions The difference in spectral width The measured two spectral widths of the multi-mode optical frequency comb are 1385.53 cm -1 、1354.13cm -1 , according to the corresponding Raman activities , The spectral width spacing difference value Less than 1% of the preset spectral width spacing difference value.

[0047] Generate a multi-mode optical frequency comb, the degeneracy detector 33 stops working, the optical frequency comb generation module starts working, the pump laser light source emits a 532 nm pump laser of fs, after being shaped by the beam shaping device 221, pumps the diamond crystal 1 to generate a multi-mode laser optical frequency comb, the remaining part of the pump laser and the multi-mode laser optical frequency comb are transmitted to the optical comb detector 23, the optical comb detector 23 analyzes the actual spectrum diagram required, and transmits it to the analysis controller 31, and the actual spectrum diagram required is 463.65 nm, 495.48 nm, 574.33 nm, 623.99 nm, 683.04 nm; 465 nm, 496.25 nm, 573.30 nm, 621.55 nm, 687.67 nm. The repetition rate is 1 KHz, the average power is 0.6 mW, and the light is linearly polarized.

[0048] The wavelength detector 31 detects the Raman laser wavelength 21 information output by the diamond crystal 2, the wavelengths are 465.94 nm, 496.78 nm, 532 nm, 572.59 nm, 619.88 nm, 675.7 nm, and transmits the communication to the controller 30; At the same time, the detection ray transmitter 321 in the stress detector 32 emits a detection ray 3211. The detection ray 3211 acts on the stress shaping stage feedback plate 323 and the diamond crystal 2 and diffracts. The diffracted detection ray 3212 is emitted to the detection ray receiver 322. The detection ray receiver 322 selects and analyzes the diffraction peak corresponding to the stress shaping stage feedback plate 323, and compares it with the standard diffraction peak of the stress shaping stage feedback plate 323. By using the diffraction peak deviation and state equation of the stress shaping feedback plate 323, it is analyzed that the stress applied by the stress applicator 33 to the diamond crystal 2 is 0 GPa. By selecting and analyzing the diffraction peak corresponding to the diamond crystal 2 and comparing it with the standard diffraction peak of the diamond crystal 2, it is analyzed that the crystal direction of stress action is <100> Crystal direction, and analyze the diffracted detection ray 3212 to obtain the lattice fringe information of the diamond crystal 2, and transmit the stress magnitude, the crystal direction of the stress action and the lattice fringe information of the diamond crystal 2 to the controller 30; The controller 30 receives the lattice fringe information of the diamond crystal 2 in a periodic arrangement. At this time, the controller 30 controls the degenerate module 3 to work normally. According to the lattice fringe information of the diamond crystal 2 and the crystal direction of the stress action, <100> The controller 30 indicates that the optical frequency comb spectrum has a wide spacing range of 535 – 1460 cm -1 At this time, the first spectral width of the optical frequency comb is selected to be 1385 cm -1 The triple degenerate vibration mode of the diamond crystal 2 is determined according to the degradation degree of the

[100] crystal orientation when it is subjected to stress. The controller 30 displays that the second spectrum width of the optical frequency comb is 1354 cm -1 The controller 30 analyzes the Raman wavelength 21 information detected by the wavelength detector 31 and obtains that there is only one optical frequency comb spectrum width spacing at this time, which is 1332.5 cm -1 , the Raman vibration activity corresponding to this spectral width spacing is , the actual spectral width spacing, the first spectral width spacing of the optical frequency comb and the stress acting crystal direction <100> Bring in It is obtained that the actual stress applied by the stress applicator 33 to the diamond crystal 2 is 0 GPa, and the theoretical stress to be applied when the first spectral width interval of the optical frequency comb is reached is -47.7 GPa. A negative value represents compressive stress. The controller 30 thus obtains a stress adjustment value of -47.7 GPa, and communicates it to the stress applicator 33. The stress applicator 33 applies a compressive stress value of 47.7 GPa to the

[100] crystal direction of the diamond crystal 2 according to the stress adjustment value.

[0049] The above adjustment and control process is repeated until the accuracy of the detected Raman laser wavelength 21 spectral width spacing and the selected optical frequency comb first spectral width spacing and optical frequency comb second spectral width spacing is within the range of ±1%. When the compressive stress applied by the stress applicator 33 to the diamond crystal 2 is 47.7 GPa, the detected Raman laser wavelength 21 is screened and analyzed as 463.65 nm, 495.48 nm, 574.33 nm, 623.99 nm, 683.04 nm; 465 nm, 496.25 nm, 573.30 nm, 621.55 nm, 687.67 nm. The two spectral width spacings of the multi-mode optical frequency comb are measured to be 1385.53 cm -1 、1354.13 cm -1 , and the corresponding Raman activities are , , which is 1385 cm away from the first spectral width of the optical frequency comb -1 、The second spectrum width of the optical frequency comb is 1354 cm -1The errors were 0.038% and 0.096% respectively, both within the error range of 1%. At this time, the degenerate multi-mode optical frequency comb device met the preset requirements and stopped working.

[0050] Example 2 The first degenerate multi-mode laser frequency comb device provided in this embodiment can be found in Figure 2 As shown, the difference between this device and Example 1 is that: The pump laser emitted by the laser pump source 331 is a femtosecond laser with a central wavelength of 1064 nm, a pulse width of 200 fs, a repetition rate of 1 KHz, an average power of 3 mW, and linearly polarized light.

[0051] Two 2*7mm diamond crystals 1 2 The surface is the laser input and output end surface.

[0052] The degeneracy detector 33 also includes a Raman enhanced cavity mirror 334, which includes a Raman enhanced cavity first cavity mirror 3341 and a Raman enhanced cavity second cavity mirror 3342 arranged on both sides of the light-transmitting end face 11 of the diamond crystal 1, and the excitation laser light source 331, the Raman enhanced cavity first cavity mirror 3341, the diamond crystal 1, and the Raman enhanced cavity second cavity mirror 3342 are optically coaxially placed in sequence.

[0053] The first spectral width of the selected optical frequency comb is 1260 cm -1 、The second spectrum width of the optical frequency comb is 1304 cm -1 、The second spectrum width of the optical frequency comb is 1330 cm -1 The multi-mode laser optical frequency comb device provided in this embodiment has an adjustment process as described in Example 1. The optical frequency combs obtained are as follows: 839 nm, 938.2 nm, 1064 nm, 1228.7 nm, 1475.3 nm, 832.8 nm, 934.3 nm, 1064 nm, 1235.4 nm, 1472.7 nm, 829.3 nm, 932.1 nm, 1064 nm, 1239.4 nm, 1484 nm. A multi-mode optical frequency comb is formed by three single-mode optical frequency combs with spectral width spacings of 1260.08 cm -1 、1304.1 cm -1 、1329.9 cm -1 , and the corresponding Raman activities are , , , selected with the first spectral width of the optical frequency comb 1260 cm-1, the second spectral width of the optical frequency comb 1304 cm -1 、The second spectrum width of the optical frequency comb is 1330 cm-1 The errors are 0.0063%, 0.0077%, and 0.0075% respectively, and the error range is within 1%.

[0054] Example 3 The multi-mode laser frequency comb device provided in this embodiment can be found in Figure 3 As shown, the difference between this device and Example 1 is that: The stress detector includes stress protection components B1 and B2, which are closely attached between the stress shaping feedback sheet 323 and are placed on the side of the plane formed by the diamond crystal 1 and the pump laser 11. Figure 3 The cross-sectional view of the stress detector 32 and the stress applicator 33 including the stress protection parts B1 and B2 along the pump laser 11 is shown. The tensile and fracture stresses of the stress protection parts B1 and B2 are slightly weaker than those of the diamond crystal, and are in communication connection with the controller 30. When the structures of the stress protection parts B1 and B2 are not damaged, positive correlation signals are transmitted to the controller 30, and the controller 30 receives the lattice fringe information of the diamond crystal 1 for subsequent work; when the structures of the stress protection parts B1 and B2 are damaged, negative correlation signals are transmitted to the controller 30, and the controller 30 stops the stress applicator 33 from applying stress to the diamond crystal 1 to protect the diamond crystal 1 from damage.

[0055] The degenerate multi-mode laser frequency comb device provided in this embodiment has an adjustment process as described in Example 1. The obtained frequency combs are as follows: 464.8 nm, 496 nm, 532 nm, 573.4 nm, 621.8 nm, 466 nm, 496.8 nm, 532 nm, 572.5 nm, 619.6 nm. The measured intervals of the two spectral widths of the multi-mode frequency comb are 1357.17 cm -1 、1329.31cm -1 , and the corresponding Raman activities are , , which is 1357 cm away from the first spectral width of the optical frequency comb -1 、The second spectrum width of the optical frequency comb is 1329 cm -1 The errors are 0.0125% and 0.0233% respectively, and the error range is within 1%.

[0056] Example 4 The multi-mode laser frequency comb device provided in this embodiment can be found in Figure 5 As shown, the difference between this device and Example 1 is that: The pump laser emitted by the laser pump source 331 is a nanosecond laser with a central wavelength of 2400 nm, a pulse width of 40 ns, a repetition rate of 1 KHz, an average power of 10 W, and linearly polarized light.

[0057] The diamond crystal contains a resonant cavity on both sides of the optical collinearity. The first lens 51 of the resonant cavity is highly transparent to the pump laser and highly reflective to the Raman laser. The second lens of the resonant cavity is highly reflective to the pump laser and partially transmits the Raman laser. The transmittance is 50%.

[0058] The adjustment process of the multi-mode laser optical frequency comb device provided in this embodiment is still the same as that of embodiment 1, and the optical frequency comb obtained is as follows: 1435.2 nm, 1796.2 nm, 2400 nm, 3615.2 nm, 7323.1 nm, 1463.6 nm, 1818.3 nm, 2400 nm, 3528.8 nm, 6662.5 nm. The measured intervals of the two spectral widths of the multi-mode optical frequency comb are 1400.56 cm -1 、1332.86 cm -1 , and the corresponding Raman activities are , , with a spacing of 1400 cm from the first spectrum width of the optical frequency comb -1 、The second spectrum width of the optical frequency comb is 1332cm -1 The errors are 0.04% and 0.0646% respectively, both within the error range of 1%.

Claims

1. A multi-mode laser optical frequency comb device, comprising a diamond crystal and an optical frequency comb generation module, characterized in that: Also includes a degeneracy control module: The diamond crystal comprises two light-transmitting end faces arranged opposite to each other, and two stress-applying faces arranged opposite to each other in parallel; The degeneracy control module is used to adjust the lattice constant of the diamond crystal, thereby adjusting the degeneracy of the Raman vibration and controlling the mode of the optical frequency comb, and the degeneracy control module includes an analysis controller, a stress controller, and a degeneracy detector that are communicatively connected; The analysis controller is used to calculate the center frequency of the optical frequency comb obtained by exciting the diamond crystal and the theoretical applied stress value according to the setting parameters. , and generate the spectrum of the multi-mode laser optical frequency comb under theoretical conditions ; The stress controller comprises a stress shaping feedback sheet, a diamond anvil, a stress applicator, a detection ray transmitter coaxially arranged with the stress applying surface, and a ray feedback controller, which are sequentially arranged on both sides of the stress applying surface; the ray feedback controller receives the theoretical applied stress value signal, and transmits it to the stress applicator; The stress applicator sets the theoretical applied stress value Applying stress to the diamond crystal through the diamond anvil and the stress shaping feedback sheet; The detection ray transmitter emits detection rays and diffracts them with the stress shaping feedback sheet and the diamond crystal. The ray detector feeds back the detected diffraction signal to the ray feedback controller and calculates the actual applied stress value. , the actual applied stress value The theoretical applied stress value The stress difference value , and according to the stress difference value Adjusting the magnitude of stress applied by the stress applicator; The degeneracy detector includes an excitation laser light source, a frequency detector and a spectrum analysis controller. The excitation laser light source excites the diamond crystal to generate the multi-mode laser light frequency comb and transmits it to the frequency detector; the frequency detector detects the spectrum of the multi-mode laser light frequency comb and transmits it to the spectrum analysis controller; the spectrum analysis controller analyzes and obtains the actual spectrum diagram , and transmits it to the analysis controller; the analysis controller analyzes the actual spectrum diagram Spectrum of multi-mode laser frequency comb under the theoretical conditions The difference in spectral width , and according to the spectral width spacing difference value , the stress deviation is calculated And feedback to the stress controller, according to the stress difference value Adjusting the magnitude of stress applied by the stress applicator; The optical frequency comb generation module is used to pump the stressed diamond crystal to generate a single-mode or multi-mode optical frequency comb, wherein the multi-mode optical frequency comb includes a plurality of single-mode optical frequency combs with spectral width intervals.

2. The multi-mode laser frequency comb device according to claim 1, characterized in that: It comprises a Raman resonant cavity mirror, wherein the Raman resonant cavity mirror comprises a first Raman resonant cavity mirror and a second Raman resonant cavity mirror arranged on both sides of the light-transmitting end face of the diamond crystal, and the first Raman resonant cavity mirror and the second Raman resonant cavity mirror are coated cavity mirrors; or The two light-transmitting end faces of the diamond crystal are film-coated end faces.

3. The multi-mode laser frequency comb device according to claim 1, characterized in that: A beam shaping mirror is included to shape the pump laser and the optical frequency comb beam, and is optically coaxially placed with the pump laser or the laser optical frequency comb.

4. The multi-mode laser frequency comb device according to claim 1, characterized in that: The degeneracy detector further includes a Raman enhanced cavity mirror, which includes a first Raman enhanced cavity mirror and a second Raman enhanced cavity mirror arranged on both sides of the light-transmitting end face of the diamond crystal, and the first Raman enhanced cavity mirror and the second Raman enhanced cavity mirror are coated cavity mirrors; or The two light-transmitting end faces of the diamond crystal are film-coated end faces.

5. The multi-mode laser frequency comb device according to claim 1, characterized in that: The theoretical applied stress value , Theoretical spectral width spacing , the crystal direction of stress action satisfies: in, , is the coordinate of the crystal direction in which stress acts, is the mass of the ith atom, which is m here. represents the Hamiltonian operator, is the vibration amplitude, is the equilibrium position of the atoms, For time, is the displacement of the atomic principle equilibrium position, is the nth spectral width spacing, n is the working degeneracy, n=1, 2, 3.

6. The multi-mode laser frequency comb device according to claim 1, characterized in that: The theoretical spectral width spacing The corresponding Raman activity intensity of the diamond crystal satisfy: in, is the linear polarizability Normal coordinates of Raman-active vibrational modes The derivative of .

7. The multi-mode laser frequency comb device according to any one of claims 1 to 6, characterized in that: The multi-mode laser frequency comb includes one spectral width spacing or multiple spectral width spacings.

8. The multi-mode laser frequency comb device according to any one of claims 1 to 6, characterized in that: The multi-mode laser frequency comb includes lasers of one frequency or multiple frequencies.

9. The multi-mode laser frequency comb device according to any one of claims 1 to 6, characterized in that: The stress controller also includes a stress protection component, which is arranged between the two stress shaping feedback plates and located on the non-light-emitting surface on the side of the diamond crystal. The tensile fracture stress and the compressive fracture stress of the stress protection component are both weaker than those of the diamond crystal. The stress protection component is communicatively connected to the analysis controller. When the stress protection component is not broken, a positive correlation signal is transmitted to the analysis controller. When the stress protection component is broken, a negative correlation signal is transmitted to the analysis controller. When the analysis controller receives the negative correlation signal, the stress controller stops applying stress to the diamond crystal.

10. A degenerate multi-mode control method, used in the multi-mode laser optical frequency comb device according to any one of claims 1 to 9, characterized in that: The degenerate multi-mode control method comprises: Step 1: Setting the parameters of the analysis controller, including the pump laser wavelength, theoretical spectral width spacing , stress action crystal direction, preset stress difference value, preset spectral width spacing difference value, working degeneracy n, the analysis controller calculates the center frequency of the excited optical frequency comb, the theoretical applied stress value according to the parameters , and generate the spectrum of the multi-mode laser optical frequency comb under theoretical conditions ; Step 2: applying stress to the diamond crystal, the analysis control 1 converts the theoretical applied stress value The ray feedback controller transmits the theoretical stress value to the stress applicator. Applying stress to the stress shaping feedback sheet and the diamond crystal through the diamond anvil; Step three, detecting the stress applied to the diamond crystal, the detection ray transmitter emits detection rays and diffracts with the stress shaping feedback sheet and the diamond crystal, the ray detector feeds back the detected diffraction ray signal to the ray feedback controller, the ray feedback controller screens and analyzes the diffraction ray signal, and calculates the actual applied stress value using the diffraction ray signal of the stress shaping feedback sheet , and analyze the actual applied stress value The theoretical applied stress value The stress difference value , and the stress difference value Transmit to the stress applicator, repeat step 2 and step 3 until the stress difference value Less than the preset stress difference value; Step 4: Detect and regulate the degeneracy of the diamond crystal. The excitation laser light source emits laser to excite the diamond crystal to generate an optical frequency comb. The frequency detector detects the spectrum of the multi-mode laser optical frequency comb and transmits it to the spectrum analysis controller. The spectrum analysis controller analyzes and obtains an actual spectrum diagram. , and transmits it to the analysis controller, which analyzes the actual spectrum diagram Spectrum of multi-mode laser frequency comb under the theoretical conditions The difference in spectral width The analysis controller is based on the spectral width spacing difference value , the stress deviation is calculated And transmitted to the stress controller, according to the stress difference value Adjust the stress applied by the stress applicator; repeat step 2, step 3, and step 4 until the spectral width spacing difference value is is smaller than the preset spectral width spacing difference value; Step five, generating a multi-mode optical frequency comb, the degeneracy detector stops working, the optical frequency comb generating module starts working, the pump laser light source emits a pump laser to pump the diamond crystal to generate a multi-mode laser optical frequency comb, the remaining part of the pump laser and the multi-mode laser optical frequency comb are transmitted to the optical comb detector, the optical comb detector analyzes and obtains the required actual spectrum diagram, and transmits it to the analysis controller to obtain the required actual spectrum diagram.

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