CN115275751B - Device for inhibiting stimulated Brillouin scattering in narrow linewidth solid Raman laser - Google Patents
Device for inhibiting stimulated Brillouin scattering in narrow linewidth solid Raman laser Download PDFInfo
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- CN115275751B CN115275751B CN202210809642.0A CN202210809642A CN115275751B CN 115275751 B CN115275751 B CN 115275751B CN 202210809642 A CN202210809642 A CN 202210809642A CN 115275751 B CN115275751 B CN 115275751B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
- H01S3/108—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering
- H01S3/109—Frequency multiplication, e.g. harmonic generation
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/08—Construction or shape of optical resonators or components thereof
- H01S3/08018—Mode suppression
- H01S3/08022—Longitudinal modes
Abstract
The invention discloses a device for inhibiting stimulated Brillouin scattering in a narrow linewidth solid Raman laser, which comprises: the laser pump comprises a laser pumping source, a resonant cavity, a Raman gain medium, a frequency doubling crystal and a temperature control module; with the increase of the Raman power in the cavity, the stimulated Brillouin scattering of the gain substance is easily caused, and the further increase of the Raman power is influenced. If the frequency doubling crystal is introduced into the resonant cavity of the solid Raman laser, the frequency doubling conversion efficiency and the resonant cavity output coupling rate are reasonably regulated and controlled, and the stimulated Brillouin scattering effect can be effectively inhibited by utilizing the nonlinear longitudinal mode inhibition capability of the frequency doubling crystal, and meanwhile, the high-power narrow-linewidth Raman laser output is maintained. The invention aims to overcome the limitation and the defect of stimulated Brillouin scattering inhibition technology in the field of high-power narrow-linewidth Raman lasers, realize the efficient inhibition of stimulated Brillouin scattering in the narrow-linewidth solid Raman lasers, and greatly improve the output power of the narrow-linewidth Raman lasers.
Description
Technical Field
The invention relates to the technical field of narrow linewidth lasers, in particular to a device for inhibiting stimulated Brillouin scattering in a narrow linewidth solid Raman laser.
Background
The high-power narrow linewidth Raman laser has the characteristics of flexible output wavelength, good beam quality, self-phase matching, high single longitudinal mode operation stability and the like, and has wide application value in the fields of precision measurement, biomedicine, quantum computation, coherent communication and the like.
Because the intensity of the optical field in the resonant cavity is higher in the narrow linewidth solid Raman laser, stimulated Brillouin Scattering (SBS) is easy to generate after the pumping power reaches a certain level. The SBS scattering resonance window of the fundamental transverse mode is small, and can be restrained by adjusting the cavity length of the resonant cavity. However, the resonance window of the multi-transverse mode SBS is large, and in the cavity length adjusting process, the corresponding multi-transverse mode SBS always meets the resonance condition, so that the multi-transverse mode SBS cannot be eliminated through cavity length adjustment. The SBS not only causes extra loss to the resonant cavity and suppresses the output power of the Raman laser, but also causes interference to stable single longitudinal mode resonance in the cavity, and the SBS is difficult to separate from the stimulated Raman scattering component by a filtering method due to small frequency shift amount of the SBS. Resulting in a broadening of the output spectrum, degrading the output performance of the laser.
At present, the scheme for suppressing SBS is mostly found in fiber lasers, but most schemes cannot be applied to free space optical paths by doping the fiber, applying stress, temperature modulation and the like. A small part of the schemes have feasibility in free space light paths, such as: CN102087452a discloses an apparatus and method for suppressing SBS using a rotating wave plate, which suppresses the occurrence of SBS in a propagation medium by dividing a laser beam into multiple segments of different polarization states using a wave plate. The method has feasibility of being applied to the traveling wave resonant cavity, but can obviously reduce the Raman gain in the cavity and also influence the polarization performance of output Stokes light.
Disclosure of Invention
The invention provides a device for inhibiting stimulated Brillouin scattering in a narrow linewidth solid Raman laser, which aims to overcome the limitation and the deficiency of a stimulated Brillouin inhibition scattering inhibiting technology in the field of high-power narrow linewidth Raman lasers, realize the efficient inhibition of stimulated Brillouin scattering in the narrow linewidth solid Raman lasers and greatly improve the output power of the narrow linewidth Raman lasers.
An apparatus for suppressing stimulated brillouin scattering in a narrow linewidth solid raman laser, the apparatus comprising: the laser device comprises a laser pumping source, a resonant cavity, a Raman gain medium, a frequency doubling crystal and a temperature control module.
The pumping light output by the pumping source enters the resonant cavity, raman laser oscillation is generated in the resonant cavity through the Raman gain medium, the pumping light energy is converted into Raman light energy, the frequency doubling crystal is introduced into the resonant cavity of the Raman laser, the conversion efficiency of the frequency doubling crystal is reasonably regulated and controlled through temperature control of the frequency doubling crystal, crystal angle control, raman light size control at the position of the frequency doubling crystal and the like, the nonlinear longitudinal mode inhibition capability of the frequency doubling crystal is utilized, the stimulated Brillouin scattering effect is inhibited, the narrow-linewidth Raman laser output is kept, and the generated narrow-linewidth Raman laser is output from one side of the resonant cavity.
The resonant cavity is a traveling wave cavity or a standing wave cavity and can be any one of a typical resonant cavity of an external cavity Raman laser, an internal cavity Raman laser, a coupling cavity Raman laser, a self-Raman laser and a pump resonance Raman laser;
the frequency doubling crystal is a two-order nonlinear effect crystal and generates a frequency doubling effect in a critical phase matching mode; the receiving bandwidth of the frequency doubling crystal is larger than the frequency shift quantity from the conversion of Raman light in the Raman gain medium to the Brillouin scattering;
the frequency doubling crystal generates a second harmonic generation process in the resonant cavity, and typical methods for controlling the frequency doubling conversion efficiency include temperature control, crystal angle control and Raman light size control of the position of the frequency doubling crystal;
the frequency doubling crystal generates a frequency doubling effect on a small part of Raman light in the resonant cavity, and generates a sum frequency effect on the Raman light and the Brillouin light, and the sum frequency effect generates intra-cavity loss on the Brillouin light to influence the generation and amplification of the Brillouin light, so that the Brillouin light is inhibited.
Further, the method comprises the steps of,
if the resonant cavity only has one beam waist position, the Raman gain medium is placed at the beam waist position, and the frequency doubling crystal is placed at the position close to the beam waist;
if the resonant cavity forms two beam waist positions, the Raman gain medium and the frequency doubling crystal are respectively placed at the beam waist positions, and the beam waist of the frequency doubling crystal is generally larger than the beam waist of the Raman gain medium;
if the resonant cavity has more than two beam waist positions, the Raman gain medium is placed at the position with the minimum beam waist, and the frequency doubling crystal is arranged at the position with the minimum beam waist.
The temperature control module is a temperature adjustment module formed by corresponding circuit modules to the semiconductor refrigerating sheet, and the typical value of the temperature accuracy is +/-0.1 ℃.
The temperature control of the frequency doubling crystal is realized by controlling the temperature control module, and the angle control and the Raman light size control of the position of the frequency doubling crystal are realized by changing the angle and the position of the frequency doubling crystal in the resonant cavity.
Further, the linewidth of the pump light output by the pump source is smaller than the raman gain linewidth of the raman gain medium.
The Raman gain line width of the Raman gain medium is smaller than the frequency shift amount of Raman light converted into Brillouin scattering.
The technical scheme provided by the invention has the beneficial effects that:
1. according to the invention, the frequency doubling crystal is introduced into the resonant cavity, so that the multi-longitudinal mode suppression effect of the frequency doubling crystal is utilized, more nonlinear loss is applied to the SBS field than that of the main mode, and the suppression effect of SBS in the resonant cavity is realized;
2. because the frequency doubling crystal has wide sources, can be matched with a wide range of wave bands, has compact integral structure, simple and convenient operation and high reliability, and can flexibly adjust the inhibition capacity by adjusting the frequency doubling efficiency of the frequency doubling crystal;
3. if a frequency doubling crystal with a high damage threshold is used, for example: liB (LiB) 3 O 5 Crystals (LBO), etc., the present invention can also be used in SBS suppression for high power lasers.
Drawings
FIG. 1 is a schematic diagram of example 1 of the present invention;
FIG. 2 is a schematic diagram of embodiment 2 of the present invention;
FIG. 3 is a schematic diagram of embodiment 3 of the present invention;
FIG. 4 is a schematic diagram of example 4 of the present invention;
fig. 5 is a graph of the comparative effect of the inhibition of typical SBS of the present invention.
In the drawings, the list of components represented by the various numbers is as follows:
1: a laser pump source; 2: a resonant cavity;
3: a raman gain medium; 4: a frequency doubling crystal;
5: a temperature control module;
21: a first cavity mirror; 22: a second cavity mirror;
23: a third cavity mirror; 24: and a fourth cavity mirror.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in further detail below.
According to the embodiment of the invention, the frequency doubling effect is introduced into the resonant cavity of the Raman laser, and the multi-longitudinal mode inhibition effect generated by the frequency doubling effect is utilized to generate additional loss on other longitudinal modes except the main longitudinal mode. Specifically, assuming that only two modes resonate within the cavity, the frequency is λ 1 Is lambda with the frequency of the main longitudinal mode 2 The light intensity of the main longitudinal mode and the inactive longitudinal mode is I respectively 1 And I 2 When the frequency doubling effect occurs, the nonlinear loss of the main longitudinal mode can be described as:
L 1 ＝k 1 I 1 +2k 1 I 2
wherein k is 1 Is a non-linear intensity dependent constant. While the nonlinear loss of the inactive longitudinal mode can be described as:
L 2 ＝k 2 I 2 +2k 2 I 1
since the main longitudinal mode and the inactive longitudinal mode are both within the receiving bandwidth of the frequency doubling crystal, the nonlinear constant k 1 ≈k 2 . When the main longitudinal mode is excited, the intensity of the main longitudinal mode is far greater than that of the non-activated longitudinal mode, so that the intensity of the non-activated longitudinal mode is negligible, and the non-linear loss of the non-activated longitudinal mode is approximately twice that of the main longitudinal mode. The generation of inactive longitudinal modes can be effectively inhibited.
Through the mode selection design of the frequency doubling crystal, such as the control of the crystal length, the receiving bandwidth of the frequency doubling crystal is larger than the Brillouin frequency shift, SBS can be regarded as an inactive longitudinal mode and more nonlinear loss is applied in the frequency doubling process, and therefore the suppression effect on SBS in the resonant cavity is achieved. Improving the output power performance and spectral characteristics of the laser.
An apparatus for suppressing stimulated brillouin scattering in a solid raman laser, comprising: the laser pumping device comprises a laser pumping source 1, a resonant cavity 2, a Raman gain medium 3, a frequency doubling crystal 4 and a temperature control module 5;
the laser pump source 1 is a narrow linewidth semiconductor laser, a narrow linewidth optical fiber laser or other narrow linewidth solid state laser type, and the linewidth of the output pump light is smaller than the raman gain linewidth of the raman gain medium 3.
The resonant cavity 2 is a traveling wave cavity or a standing wave cavity, and may be any one of an external cavity raman laser, an internal cavity raman laser, a coupled cavity raman laser, a self-raman laser, and a typical resonant cavity of a pump resonant raman laser, which is not limited in the embodiment of the present invention.
The raman gain medium 3 is any one of solid raman media, and includes: but are not limited to, yttrium vanadate, tungstate, nitrate, quartz, silicon, diamond, etc. raman crystal materials. The raman gain linewidth is required to be smaller than the frequency shift amount of the light converted into brillouin scattering by Yu Laman. The raman gain medium 3 is placed at the beam waist of the resonator 2, and if the resonator 2 forms two beam waists, it is placed at the beam waist with the smallest spot radius at the focal point.
The frequency doubling crystal 4 is a second-order nonlinear effect crystal, and generates a frequency doubling effect in the device for inhibiting stimulated Brillouin scattering in the narrow linewidth solid Raman laser in a critical phase matching mode; typically LiB 3 O 5 (LBO)、β-BaB 2 O 4 (BBO)、KH 2 PO 4 (KDP) crystals. The frequency doubling crystal 4 is designed in a cutting way, so that the second harmonic is generated for the output stimulated Raman scattering wavelength, and the phase matching is the first phase matching. The design of the frequency doubling crystal 4 simultaneously needs to meet the requirement that the receivable bandwidth is larger than the frequency shift amount of the conversion of the Raman light in the Raman gain medium 3 to the Brillouin scattering; the frequency doubling crystal 4 needs to be disposed inside the resonator 2 if the resonator 2 has only one focal position, for example: the frequency doubling crystal 4 can be arranged at a position close to the beam waist of the light beam; if the resonant cavity 2 forms two beam waists, the frequency doubling crystal 4 is arranged at a focal point with a relatively large spot radius at the beam waists. Meanwhile, the frequency doubling crystal 4 is arranged on the temperature control module 5, and the temperature is regulated through the temperature control module 5And (5) a section.
When more than two beam waists are less likely to occur, the raman gain medium 3 is arranged at a position where the spot radius from the beam waists is smallest, and the frequency doubling crystal 4 is arranged at a position where the spot radius from the beam waists is next smallest.
The temperature control module 5 is typically a temperature adjusting module formed by corresponding circuit modules of semiconductor refrigeration sheets, or other modules capable of realizing temperature adjustment. The temperature control method is used for temperature control of the frequency doubling crystal. A typical value for the temperature accuracy is adjusted to + 0.1 c.
The frequency doubling crystal 4 is connected into the resonant cavity 2 of the solid Raman laser to perform frequency doubling conversion on Raman light, and the high loss generated by the frequency doubling crystal 4 on an inactive longitudinal mode and the coverage of the receiving bandwidth of the frequency doubling crystal 4 on Brillouin wave band are utilized to inhibit SBS in the resonant cavity 2, and the inhibition effect of SBS is changed by controlling the frequency doubling conversion efficiency.
Typical methods for controlling the frequency doubling conversion efficiency include temperature control, crystal angle control, and raman optical size control of the position of the frequency doubling crystal 4.
The temperature control of the frequency doubling crystal 4 is realized by controlling the temperature control module 5, and the angle control and the raman light size control of the frequency doubling crystal 4 are realized by changing the angle and the position of the frequency doubling crystal 4 in the resonant cavity 2.
The optical path trend of the device for inhibiting stimulated Brillouin scattering in the solid-state Raman laser is as follows:
the pump light output by the pump source 1 enters the resonant cavity 2, and one of the cavity mirrors of the resonant cavity 2 is used as an output port of the Raman light through the Raman gain medium 3 in the resonant cavity 2.
The pump light generates stimulated raman scattering when passing through the raman gain medium 3, converts the pump light into raman light, and the raman light oscillates and amplifies in the resonant cavity 2.
The Raman light resonating in the resonant cavity 2 passes through the frequency doubling crystal 4 to generate second harmonic, the multi-longitudinal mode suppression effect of the second harmonic acts on the Raman light field, and the conversion efficiency of the frequency doubling crystal is reasonably regulated and controlled through temperature control of the frequency doubling crystal, crystal angle control, raman light size control of the position where the frequency doubling crystal is located and the like, so that the stimulated Brillouin scattering effect is effectively suppressed, and the narrow linewidth Raman laser output is maintained. The generated narrow linewidth Raman laser is finally output through an output port of the resonant cavity.
The frequency doubling crystal is connected into a resonant cavity of the solid Raman laser to perform frequency doubling conversion on Raman light, and the SBS in the resonant cavity is restrained by utilizing high loss generated by the frequency doubling crystal on an inactive longitudinal mode and coverage of the receiving bandwidth of the frequency doubling crystal on a Brillouin wave band, and the restraining effect of the SBS is changed by controlling the second harmonic conversion efficiency.
By introducing the frequency doubling crystal into the resonant cavity of the Raman laser, the stimulated Brillouin scattering effect can be effectively inhibited by utilizing the nonlinear longitudinal mode inhibition capability of the frequency doubling crystal, the narrow linewidth Raman laser output is kept, and the generated narrow linewidth Raman laser is finally output through the output port of the resonant cavity.
Example 1
Fig. 1 is a schematic structural diagram of embodiment 1 of the present invention, in which embodiment 1 is a confocal resonant cavity (a common technical term in the art) composed of a first cavity mirror 21 and a second cavity mirror 22, which is commonly used in external cavity raman lasers. The laser pumping source 1 is a 1064nm narrow linewidth fiber laser, the maximum power is 70W, and linearly polarized light is output. In the use process, parameters, selected wavelengths, output power and the like of the pump light source are selected according to the needs in practical application, and the embodiment of the invention is not limited to this. The pump light enters the resonant cavity 2 after being output from the pump source 1, and the resonant cavity 2 is composed of a first cavity mirror 21 and a second cavity mirror 22. The first cavity mirror 21 is a concave mirror, is coated with an antireflection film with a pumping wavelength of 1064nm, a high reflection film with a Raman wavelength of 1240nm, and an antireflection film with a second harmonic wavelength of 620nm, and is used as an input cavity mirror for pumping light into a confocal resonant cavity. The second cavity mirror 22 of the resonant cavity 2 is a plano-concave mirror, is coated with a high reflection film with a pumping wavelength of 1064nm, is partially transmissive with a raman wavelength of 1240nm, has a transmissivity of 1% for a typical value of 70W pumping source power, is an antireflection film with a second harmonic wavelength of 620nm, and is used as an output cavity mirror of a laser, and the generated raman light is output from the second cavity mirror 22 to the outside of the cavity. The Raman gain medium 3 is diamond crystal, two of which areThe end is plated with antireflection films of 1064nm,1240nm and 620nm, and the Brillouin frequency shift is about 0.36nm. The frequency doubling crystal 4 is 4x4 mm 3 Both ends of the LBO crystal are plated with antireflection films of 1064nm,1240nm and 620 nm. The cutting angle is θ=85.6°,and adopting a phase matching type, wherein the optimal matching temperature is 40 ℃, the receivable bandwidth reference value is 2.5nm, and the receivable temperature bandwidth reference value is 19.1 ℃. The frequency doubling crystal 4 is arranged on the temperature control module 5, the temperature control module 5 is a module for realizing temperature control by utilizing a semiconductor refrigerating sheet, and the control precision is +/-0.1 ℃. The frequency doubling crystal 4 is spaced 1mm from the diamond.
When the pump power is high enough, raman light oscillation is generated in the resonant cavity 2, part of the raman light is converted into frequency-doubled light due to the high intensity of the optical field in the resonant cavity 2. Effectively inhibit the generation of SBS effect, thereby achieving the effect of improving SBS threshold. And the higher the frequency doubling conversion efficiency is, the larger the extra nonlinear loss of SBS light is, and the stronger the inhibition effect is. At the pump power of 68W and the temperature of 40 ℃ set by the temperature control module 5, SBS is stably inhibited, and the second harmonic conversion efficiency is 28.8%, so that stable Stokes single longitudinal mode output of 10.4W is generated. After the SBS inhibition capability and the output power are balanced by changing the temperature of the frequency doubling crystal 4, the temperature control module 5 sets the temperature to 49 ℃, the second harmonic conversion efficiency reaches 10.6%, so that stable inhibition of SBS under the same pumping power can be realized, and 11.7W of Stokes single longitudinal mode output is generated.
Example 2
Fig. 2 is a schematic structural diagram of embodiment 2 of the present invention, and embodiment 2 is a three-mirror standing wave resonant cavity formed by a first mirror 21, a second mirror 22, and a third mirror 23, which are commonly used in an external cavity raman laser, and is formed by a V-shaped, wherein the first mirror 21 is installed at the center node position of the V-shaped, the second mirror 22 is used as an output mirror, and an optical field in the resonant cavity is round-trip operated, so as to form a standing wave cavity structure. Unlike embodiment 1, the structure of the resonant cavity 2 is different, and the raman gain medium 3 and the frequency doubling crystal 4 are respectively installed at the foci of both arms of the resonant cavity 2. In addition, the third cavity mirror 23 is a plano-concave mirror, whose coating is identical to that of the first cavity mirror 21, and the frequency doubling crystal 4 can be coated with no pump light wavelength since no pump light passes through the optical path. The arrangement and operation of the frequency doubling crystal 4 are the same as those of embodiment 1, and the embodiments of the present invention are not described herein.
Example 3
Fig. 3 is a schematic structural diagram of embodiment 3 of the present invention, and embodiment 3 is an 8-shaped traveling wave cavity (a common technical term in the art) commonly formed by a first cavity mirror 21, a second cavity mirror 22, a third cavity mirror 23 and a fourth cavity mirror 24 in a pump resonance raman laser, and an optical field in the resonant cavity is operated in a unidirectional manner, so as to form a traveling wave cavity structure. The difference from embodiment 1 is that the resonant cavity 2 is a traveling wave cavity, and the raman gain medium 3 and the frequency doubling crystal 4 are respectively installed at two focal points on both sides of the resonant cavity 2. In addition, the first cavity mirror 21 is a plano-concave mirror, and is used as an input cavity mirror and an output cavity mirror, and is coated with a part of transmission film for pump light and Raman light, wherein the typical transmittance of the part of transmission film for the pump light and Raman light wave band is 10% for the laser pump source 1 with 70W, and is an antireflection film for a second harmonic light field. In this embodiment, the first endoscope is used as an input endoscope and an output endoscope, and other endoscopes can be designed as output endoscopes according to different designs. The rest of the resonant cavity mirrors (the second cavity mirror 22, the third cavity mirror 23 and the fourth cavity mirror 24) are plated with high-reflection films for the pump light and the Raman light in the cavity and antireflection films for the second harmonic light, so that oscillation of the pump light and the Raman light field in the resonant cavity is formed. In this embodiment, the third cavity mirror 23 and the fourth cavity mirror 24 are plane mirrors, which may be concave mirrors according to different designs. The arrangement of the frequency doubling crystal 4 is identical to that of the operation mode embodiment 1, and the description of the embodiment of the present invention is omitted here.
Example 4
Fig. 4 is a schematic structural diagram of embodiment 4 of the present invention, and embodiment 4 is a semi-confocal resonant cavity (a common technical term in the art) composed of a first cavity mirror 21 and a second cavity mirror 22, which is commonly used in the cavity raman laser. The laser pumping source 1 consists of a 808nm semiconductor laser 11, a resonant cavity 2 and a laser medium 12. The first cavity mirror 21 is a concave mirror coated with an antireflection film for 808nm and 620nm and a high reflection film for 1064nm and 1240nm, and the second cavity mirror 22 is a plane mirror coated with an antireflection film for 808nm and 620nmThe typical value of the transmittance of an antireflection film is 1% for a high reflection film of 1064nm and for a partial transmission film of 1240 nm. The laser medium 12 is Nd: YVO 4 The crystal, the Raman gain medium 3 is diamond crystal, and the frequency doubling crystal 4 is LBO crystal. After the 808nm optical field output by the semiconductor laser 11 enters the resonant cavity, 1064nm pump light is generated by passing through the laser medium 12. The obtained pump light is oscillated in the resonator 2 to enhance and 1240nm raman light is generated by the diamond crystal. The arrangement of the frequency doubling crystal 4 is identical to that of the operation mode embodiment 1, and the description of the embodiment of the present invention is omitted here.
Example 5
Fig. 5 is a graph of the comparative effect of typical SBS inhibition in an embodiment of the present invention. In the absence of the frequency doubling crystal 4, as shown in the lowest diagram, in addition to the raman light component having a center wavelength of 1239.6nm, a significant SBS component was found in the spectrum of the output light, with the center wavelength being 1239.9nm. This represents the presence of SBS components in the output light. When the frequency doubling crystal 4 is introduced into the resonant cavity 2, the second harmonic conversion efficiency of the frequency doubling crystal 4 is adjusted under the same raman optical output power, and when the second harmonic power is lower (about several milliwatts), the phenomenon of instability of the SBS spectrum is observed, which indicates that the SBS component is slightly suppressed, and when the second harmonic power is higher (usually more than 500 milliwatts depending on the actual situation), the SBS spectrum disappears, which indicates that the SBS is completely suppressed.
The embodiments of the present invention are not limited to the above examples, but various modifications and changes of the present invention are possible. Any changes, modifications, substitutions, combinations, simplifications, etc. that fall within the spirit and principles of the present invention are intended to be included within the scope of the present invention.
The embodiment of the invention does not limit the types of other devices except the types of the devices, so long as the devices can complete the functions.
Those skilled in the art will appreciate that the drawings are schematic representations of only one preferred embodiment, and that the above-described embodiment numbers are merely for illustration purposes and do not represent advantages or disadvantages of the embodiments.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.
Claims (6)
1. An apparatus for suppressing stimulated brillouin scattering in a narrow linewidth solid raman laser, the apparatus comprising: the laser pump source, the resonant cavity, the Raman gain medium, the frequency doubling crystal and the temperature control module are characterized in that,
the pumping light output by the pumping source enters a resonant cavity, raman laser oscillation is generated in the resonant cavity through a Raman gain medium, pumping light energy is converted into Raman light energy, a frequency doubling crystal is introduced into the resonant cavity of the Raman laser, the conversion efficiency of the frequency doubling crystal is regulated and controlled through temperature control of the frequency doubling crystal, crystal angle control and Raman light size control of the position where the frequency doubling crystal is located, the nonlinear longitudinal mode inhibition capability of the frequency doubling crystal is utilized, the stimulated Brillouin scattering effect is inhibited, the narrow-linewidth Raman laser output is kept, and the generated narrow-linewidth Raman laser is output from one side of the resonant cavity;
the Raman gain line width of the Raman gain medium is smaller than the frequency shift amount of Raman light converted into Brillouin scattering; the receiving bandwidth of the frequency doubling crystal is larger than the frequency shift quantity from the conversion of Raman light in the Raman gain medium to the Brillouin scattering;
the frequency doubling crystal generates a frequency doubling effect on part of Raman light in the resonant cavity, and generates a sum frequency effect on the Raman light and the Brillouin light, and the sum frequency effect generates intra-cavity loss on the Brillouin light to influence the generation and amplification of the Brillouin light, so that the Brillouin light is inhibited.
2. The device for suppressing stimulated Brillouin scattering in a narrow linewidth solid Raman laser according to claim 1, wherein,
the resonant cavity includes: confocal resonant cavity, three mirror standing wave resonant cavity, 8 style of calligraphy travelling wave cavity or semi confocal resonant cavity.
3. The device for suppressing stimulated Brillouin scattering in a narrow linewidth solid Raman laser according to claim 1, wherein,
the frequency doubling crystal is a second-order nonlinear effect crystal and generates a frequency doubling effect in a critical phase matching mode;
the frequency doubling crystal generates a second harmonic generation process in the resonant cavity, and the method for controlling the frequency doubling conversion efficiency comprises temperature control, crystal angle control and Raman light size control of the position of the frequency doubling crystal;
the temperature control of the frequency doubling crystal is realized by controlling the temperature control module, and the angle control and the Raman light size control of the position of the frequency doubling crystal are realized by changing the angle and the position of the frequency doubling crystal in the resonant cavity.
4. The device for suppressing stimulated Brillouin scattering in a narrow linewidth solid Raman laser according to claim 1, wherein,
if the resonant cavity only has one beam waist position, the Raman gain medium is placed at the beam waist position, and the frequency doubling crystal is placed at the position close to the beam waist;
if the resonant cavity forms two beam waist positions, the Raman gain medium and the frequency doubling crystal are respectively placed at the beam waist positions, and the beam waist of the frequency doubling crystal is generally larger than the beam waist of the Raman gain medium;
if the resonant cavity has more than two beam waist positions, the Raman gain medium is placed at the position with the minimum beam waist, and the frequency doubling crystal is arranged at the position with the minimum beam waist.
5. The device for inhibiting stimulated brillouin scattering in a narrow linewidth solid raman laser according to claim 1, wherein the temperature control module is a temperature adjusting module formed by a semiconductor refrigerating sheet corresponding to a circuit module, and a typical value of adjusting temperature accuracy is +/-0.1 ℃.
6. The device for suppressing stimulated brillouin scattering in a narrow linewidth solid raman laser according to claim 1, wherein the pump source outputs pump light having a linewidth smaller than a raman gain linewidth of the raman gain medium.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5153887A (en) * | 1991-02-15 | 1992-10-06 | Krapchev Vladimir B | Infrared laser system |
| US5721748A (en) * | 1996-09-11 | 1998-02-24 | Trw Inc. | Intracavity doubled solid state Raman laser system |
| CN1714313A (en) * | 2002-11-21 | 2005-12-28 | 古河电气工业株式会社 | Light source in optical transmission system, waveform shaper, optical pulse train generator, and optical reproduction system |
| AU2006200826A1 (en) * | 2000-07-26 | 2006-03-16 | Macquarie Research Ltd | A stable solid state raman laser and a method of operating same |
| US8472486B1 (en) * | 2011-08-17 | 2013-06-25 | The United States Of America As Represented By The Secretary Of The Air Force | Seeded raman amplifier for applications in the 1100-1500 nm spectral region |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| EP1241746A1 (en) * | 2001-03-14 | 2002-09-18 | Europäische Organisation für astronomische Forschung in der südlichen Hemisphäre | Narrow band high power fibre lasers |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5153887A (en) * | 1991-02-15 | 1992-10-06 | Krapchev Vladimir B | Infrared laser system |
| US5721748A (en) * | 1996-09-11 | 1998-02-24 | Trw Inc. | Intracavity doubled solid state Raman laser system |
| AU2006200826A1 (en) * | 2000-07-26 | 2006-03-16 | Macquarie Research Ltd | A stable solid state raman laser and a method of operating same |
| CN1714313A (en) * | 2002-11-21 | 2005-12-28 | 古河电气工业株式会社 | Light source in optical transmission system, waveform shaper, optical pulse train generator, and optical reproduction system |
| US8472486B1 (en) * | 2011-08-17 | 2013-06-25 | The United States Of America As Represented By The Secretary Of The Air Force | Seeded raman amplifier for applications in the 1100-1500 nm spectral region |
Non-Patent Citations (1)
| Title |
|---|
| 单频连续波金刚石拉曼激光器研究进展(特邀);李牧野等;《红外与激光工程》;第51卷(第6期);20210970-1-20210970-11 * |
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