CN116505356A - Double-amplification inner cavity Raman laser - Google Patents

Double-amplification inner cavity Raman laser Download PDF

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CN116505356A
CN116505356A CN202310711108.0A CN202310711108A CN116505356A CN 116505356 A CN116505356 A CN 116505356A CN 202310711108 A CN202310711108 A CN 202310711108A CN 116505356 A CN116505356 A CN 116505356A
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light
fundamental frequency
reflector
amplifying
double
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白振旭
郑浩
王雨雷
吕志伟
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Hebei University of Technology
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Hebei University of Technology
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES 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
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08Construction or shape of optical resonators or components thereof
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES 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
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06Construction or shape of active medium
    • H01S3/0602Crystal lasers or glass lasers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES 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
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08Construction or shape of optical resonators or components thereof
    • H01S3/081Construction or shape of optical resonators or components thereof comprising three or more reflectors
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES 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
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/10007Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES 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
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/10084Frequency control by seeding
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES 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
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/101Lasers provided with means to change the location from which, or the direction in which, laser radiation is emitted
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES 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
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/106Controlling 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
    • H01S3/108Controlling 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
    • H01S3/1086Controlling 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 using scattering effects, e.g. Raman or Brillouin effect
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01SDEVICES 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
    • H01S3/00Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/30Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00Technologies having an indirect contribution to adaptation to climate change
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  • Optics & Photonics (AREA)
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  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
  • Lasers (AREA)

Abstract

The invention discloses a dual-amplification inner cavity Raman laser, and relates to a solid laser amplifier. The invention aims to solve the problems that the existing Raman laser amplifier is mostly of one-stage coaxial amplification, needs a certain space for focusing, and needs a plurality of Raman crystals to realize, so that the structure of the Raman laser amplifier is complex and the energy utilization rate is low. A dual amplification cavity raman laser comprising: the device comprises a first double-light amplifying reflector, a second double-light amplifying reflector, a first seed light amplifying reflector, a second fundamental frequency light amplifying reflector, a first fundamental frequency light crystal module, a second fundamental frequency light crystal module, a Raman crystal module, a first LD pump source, a second LD pump source, a fundamental frequency light coupling lens group, a fundamental frequency light module, a seed light coupling lens group and a seed light module; and the first fundamental frequency optical crystal module and the second fundamental frequency optical crystal module are respectively arranged above and below the Raman crystal module in the vertical direction. The invention belongs to the technical field of laser.

Description

Double-amplification inner cavity Raman laser
Technical Field
The invention belongs to the technical field of laser, relates to a solid laser amplifier, and particularly relates to a Raman laser amplifier.
Background
Since the advent of lasers, the laser has been used in a wider and wider range of applications, and with the development of each field, there is a higher and higher demand for laser output power. Since under high power pump lasers, the laser crystals can produce severe thermal effects, even exceeding the damage threshold of the laser crystals, causing damage to the device, and the power output of the individual lasers can reach saturation. These factors limit the laser output power, and thus in order to further increase the laser output power, a technique of laser amplifier is used.
The basic physical process of a laser amplifier is the same as that of a laser. Higher laser output can be achieved by a laser amplifier, and the laser amplifier is now a common technical means for high-power laser output.
At present, most of laser amplifiers utilize seed light to pass through a laser crystal to convert pumping laser into seed light, so that the laser output power of the seed light is improved. Multi-stage amplification has been developed to pass seed light through multiple laser crystals for multiple gain amplification. The laser power output can be improved and amplified after passing through the laser crystal once, the structure is flexible, the size is large, and the single amplification efficiency is limited. Therefore, the design is carried out by utilizing the polarization characteristic of the laser, so that the seed light can pass through the laser crystal for multiple times, and the conversion efficiency is further improved, but the complexity of the structure is increased.
Raman amplifier based on Raman effect, wherein fundamental frequency light photons are incident into Raman crystal and generate inelastic collision with phonons in the crystal, so that the frequency is v l Exciting a large number of molecules to a virtual energy level u to form a particle inversion number, and then generating a laser effect to radiate a frequency v s1 One of (2)The stokes light of the order takes the stokes light of the first order as the fundamental frequency light, and the process is repeated to generate the stokes light of higher order; and v l And v s1 Referred to as raman shift.
Disclosure of Invention
The invention aims to solve the problems that the existing Raman laser amplifier is mostly in one-stage and one-stage coaxial amplification, needs a certain space for focusing, and needs a plurality of Raman crystals to realize, so that the structure of the Raman laser amplifier is complex and the energy utilization rate is low.
A dual amplification cavity raman laser comprising: the device comprises a first double-light amplifying reflector, a second double-light amplifying reflector, a first seed light amplifying reflector, a second fundamental frequency light amplifying reflector, a first fundamental frequency light crystal module, a second fundamental frequency light crystal module, a Raman crystal module, a first LD pump source, a second LD pump source, a fundamental frequency light coupling lens group, a fundamental frequency light module, a seed light coupling lens group and a seed light module;
Setting a coordinate axis, wherein the x-axis direction is a horizontal direction, the z-axis direction is a vertical direction, and determining a y-axis according to a right-hand rule;
a fundamental frequency optical crystal module I and a fundamental frequency optical crystal module II are respectively arranged on the upper side and the lower side of the Raman crystal module in the vertical direction;
the first fundamental frequency optical crystal module, the Raman optical crystal module and the second fundamental frequency optical crystal module are closely placed, so that a sandwich structure is formed;
the first LD pump source and the second LD pump source are respectively arranged in the horizontal directions of the first fundamental frequency optical crystal module and the second fundamental frequency optical crystal module, pumping light excited by the first LD pump source horizontally enters the first fundamental frequency optical crystal module along the x-axis, and pumping light excited by the second LD pump source horizontally enters the second fundamental frequency optical crystal module along the x-axis;
in the vertical direction of the sandwich structure, a double-light amplifying reflector I is arranged on the first fundamental frequency optical crystal module, and a double-light amplifying reflector II is arranged under the second fundamental frequency optical crystal module;
the seed light magnifying reflector I is arranged on the left side of the double light magnifying reflector IThe seed light magnifying reflector and the double light magnifying reflector have an included angle alpha 2
The fundamental frequency light magnifying reflector II is arranged on the right side of the double light magnifying reflector II, and the included angle between the fundamental frequency light magnifying reflector II and the double light magnifying reflector II is as follows according to the geometric relationship α 1 The fundamental frequency light horizontally enters the vertical direction z-axis angle after being reflected by the fundamental frequency light magnifying reflector II;
the seed optical module comprises a seed optical coupling lens group and a seed light source, and is arranged on the lower side of the double-light amplifying reflector;
the fundamental frequency optical module comprises a fundamental frequency optical coupling lens group and fundamental frequency light I, and the fundamental frequency optical module is arranged on one side of a fundamental frequency light amplifying reflector II.
The beneficial effects of the invention are as follows:
the invention provides a dual-amplification inner cavity Raman laser, which is characterized in that fundamental frequency light is overlapped with a resonant cavity of seed light, the seed light is oscillated for multiple times in the cavity based on a traveling wave laser amplification technology, so that the overlapped volume of the seed light and the fundamental frequency light is increased, the energy utilization rate is further improved, the output power of the laser is greatly improved, the space structure is optimized, the structure is simple, the energy utilization rate is high, and the output power is high.
The invention simplifies the cavity structure of the laser amplifier by combining the seed light amplifying process and the fundamental frequency light amplifying process, and further miniaturizes the amplifier.
The invention puts the fundamental frequency light crystal and the seed light crystal in the resonant cavity, reduces the loss caused by the complex cavity structure, increases the power density of the fundamental frequency light, improves the conversion efficiency of the seed light, and has high energy utilization rate and large output power.
Drawings
FIG. 1 is a top view of a first embodiment of the present invention;
FIG. 2 is a schematic overall 3D block diagram of a first embodiment of the invention;
in the figure: 1-a double-light amplifying reflector I; 2-a second double-light amplifying reflector; 3-seed light magnifying reflector I; 4-a fundamental frequency light amplifying reflector II; 5-fundamental frequency optical crystal module I; 6-a second fundamental frequency optical crystal module; a 7-raman crystal module; 8-LD pump source one; 9-LD pumping source II; 10-fundamental frequency optical coupling lens group; 11-fundamental frequency optical module; 12-seed optical coupling lens group; 13-a seed light module;
FIG. 3 is a schematic diagram of the operation of the present invention;
fig. 4 is a diagram of an exemplary modeling of a formula.
Detailed Description
The first embodiment is as follows: the dual amplification cavity raman laser of this embodiment comprises: a double-light amplifying reflector I1, a double-light amplifying reflector II 2, a seed light amplifying reflector I3, a fundamental frequency light amplifying reflector II 4, a fundamental frequency light crystal module I5, a fundamental frequency light crystal module II 6, a Raman crystal module 7, an LD pumping source I8, an LD pumping source II 9, a fundamental frequency light coupling lens group 10, a fundamental frequency light module 11, a seed light coupling lens group 12 and a seed light module 13;
double amplification refers to: the double-light amplifying reflector 1 and the double-light amplifying reflector 2 can amplify light with two wavelengths of fundamental frequency light and seed light;
For convenience of explanation, setting the coordinate axis as shown in fig. 1, wherein the x-axis direction is a horizontal direction, the z-axis direction is a vertical direction, and determining the y-axis according to the right-hand rule;
the first fundamental frequency optical crystal module 5 and the second fundamental frequency optical crystal module 6 are respectively arranged on the upper side and the lower side of the Raman crystal module 7 in the vertical direction;
the first fundamental frequency optical crystal module 5, the Raman optical crystal module 7 and the second fundamental frequency optical crystal module 6 are closely arranged to form a sandwich structure;
the first LD pump source 8 and the second LD pump source 9 are respectively arranged in the horizontal directions of the fundamental frequency optical crystal module I5 and the fundamental frequency optical crystal module II 6, the first LD pump source 8 excites pump light to horizontally cross-directionally enter the fundamental frequency optical crystal module I5 along the x-axis, and the second LD pump source 9 excites pump light to horizontally cross-directionally enter the fundamental frequency optical crystal module II 6 along the x-axis;
in the vertical direction of the sandwich structure, a double-light amplifying reflector 1 is arranged on a fundamental frequency optical crystal module I5, and a double-light amplifying reflector II 2 is arranged under a fundamental frequency optical crystal module II 6;
the seed light amplifying reflector I3 is arranged at the left side of the double light amplifying reflector I1, and the included angle between the seed light amplifying reflector I3 and the double light amplifying reflector I1 is alpha 2 (included angle (acute angle) of intersection point of extended line 3 of the fundamental frequency light magnifying reflector and extended line 1 of the double light magnifying reflector at x axis);
The fundamental frequency light amplifying reflector II 4 is arranged on the right side of the double light amplifying reflector II 2, and the included angle between the fundamental frequency light amplifying reflector II 4 and the double light amplifying reflector II 2 is as follows according to the geometric relationα 1 The fundamental frequency light horizontally enters and is reflected by the second fundamental frequency light magnifying reflector 4 and then forms an angle with the vertical z-axis;
the seed light module 13 comprises a seed light coupling lens group 12 and a seed light source, and the seed light module 13 is arranged at the lower side of the two double-light amplifying reflectors 2;
the fundamental frequency optical module 11 comprises a fundamental frequency optical coupling lens group 10 and a fundamental frequency light I, and the fundamental frequency optical module 11 is arranged on one side of a fundamental frequency light magnifying reflector II 4.
The second embodiment is as follows: in this embodiment, unlike the first embodiment, the seed light module 13 excites the seed light, the seed light is vertically incident through the seed light coupling lens group 12, and is reflected by the first seed light amplifying mirror 3, and then periodically reflected between the first double light amplifying mirror 1 and the second double light amplifying mirror 2, and each time the reflected seed light has a horizontal displacement of:
l 2 =L 2 *tan2α 2 (1)
final number of reflections j 2 Approximately satisfying the formula (after passing through the raman crystal module (7) and exiting the cavity):
wherein d 2 The lens length L of the double-light magnifying reflector I1 and the double-light magnifying reflector II 2 2 Is the distance between the first double-light amplifying reflector 1 and the second double-light amplifying reflector 2, l 2 For each reflected seed light horizontal displacement, x is the multiplier; alpha 2 An included angle between the seed light amplifying reflector I3 and the double light amplifying reflector I1;
as the requirements meet the practical significance:
if j is obtained 2 The parity is directly judged for the integer;
if j is obtained 2 The decimal fraction is not discarded, and then j is judged 2 Parity of (c);
if j 2 When the number is even, the emergent direction of the seed light is opposite to the incident direction;
if j 2 When the number is odd, the emergent direction of the seed light is the same as the incident direction.
Other steps and parameters are the same as in the first embodiment.
And a third specific embodiment: in this embodiment, unlike the first or second embodiment, the fundamental frequency light module 11 excites the fundamental frequency light, the fundamental frequency light is horizontally incident through the fundamental frequency light coupling lens set 10, and is reflected by the fundamental frequency light magnifying reflector two 4, and then periodically reflected between the dual light magnifying reflector two 1 and the dual light magnifying reflector two 2, and each time the reflected fundamental frequency light has a horizontal displacement as follows:
l 1 =L 2 *tanα 1 (3)
final number of reflections j 1 The approximation satisfies the formula:
wherein d 2 The lens length L of the double-light magnifying reflector I1 and the double-light magnifying reflector II 2 2 Is the distance between the first double-light amplifying reflector 1 and the second double-light amplifying reflector 2, l 1 For each reflection of fundamental light a horizontal displacement alpha 1 Is reflected by the second fundamental frequency light amplifying reflector 4 for the horizontal incidence of the fundamental frequency lightAn included angle of a z-axis in the vertical direction;
as the requirements meet the practical significance:
if j is obtained 1 The parity is directly judged for the integer;
if j is obtained 1 The decimal fraction is not discarded, and then j is judged 1 Parity of (c);
if j 1 If the number is even, the outgoing direction of the fundamental frequency light is opposite to the incoming direction;
if j 1 When the number is odd, the outgoing direction of the fundamental frequency light is the same as the incoming direction.
Other steps and parameters are the same as in the first or second embodiment.
The specific embodiment IV is as follows: the difference between this embodiment and one to three embodiments is that the seed light and the fundamental light intersect in a periodic reflection manner between the first two magnifying reflectors 1 and the second two magnifying reflectors 2 as shown in fig. 3, and an angle β is periodically generated 1 Cross-coupling, satisfying the formula:
β 1 =α 1 +2α 2 (5)
beta in 1 Is the interaction angle between the fundamental frequency light and the seed light.
Other steps and parameters are the same as in one to three embodiments.
Fifth embodiment: in this embodiment, one to four different from the specific embodiment, in the raman crystal module 7, the seed light periodically intersects with the fundamental frequency light, and frequency shift occurs, that is, the frequency v of the seed light 2 And fundamental frequency optical frequency v 1 The formula is satisfied:
in the middle ofIs Planck constant, deltav is Raman translation generated by collision of fundamental frequency light and phonons in Raman crystal module 7, lambda 1 Is the wavelength lambda of fundamental frequency light 2 Is the wavelength of the seed light; v (v) 2 =1/λ 2 ,ν 1 =1/λ 1
The fundamental frequency light is fundamental frequency light I or fundamental frequency light II; deltav is fundamental frequency light one, lambda 1 Is fundamental frequency light with a wavelength v 1 Is a fundamental frequency light frequency; when Deltav is fundamental frequency light II, lambda 1 Is fundamental frequency light with two wavelengths, v 1 Is the fundamental frequency light two frequencies.
Other steps and parameters are the same as in one to four embodiments.
Specific embodiment six: the difference between this embodiment and one of the first to fifth embodiments is that the seed light and the fundamental frequency light periodically reflect and intersect between the first two light amplifying reflectors 1 and 2 as shown in fig. 3, and the minimum interaction times are determined when the collinear single conversion gain of the seed light and the fundamental frequency light is the same as the crossed conversion gain of the seed light and the fundamental frequency light; the specific process is as follows:
wave equation and material equation are (a) in (7) and (b) in (7), respectively;
wherein n is the refractive index of the seed light or fundamental frequency light in the Raman crystal module 7, c is the light velocity in vacuum, μ 0 For permeability in vacuum, P NL Is nonlinear electric polarization rate, Q is acoustic wavelet, T is phonon life, omega v Is the angular frequency of phonons χ (3) Is nonlinear polarization rate gamma v The dispersion response of nonlinear polarization intensity, E is the electric field intensity of light, t is the acting time of seed light or fundamental frequency light in the Raman crystal module 7, epsilon 0 For fundamental frequency light amplitude, z 0 The displacement of the seed light or the fundamental frequency light back and forth between the double-light amplifying reflector I1 and the double-light amplifying reflector II 2;
the fundamental frequency light in the formula (7) is fundamental frequency light I or fundamental frequency light II;
equation (7) applies equally to fundamental light one and fundamental light two;
beta is arranged between the fundamental frequency light one and the seed light 1 Obtaining a coupling equation formula (8) based on formula (7);
in the formula, j is only j for the first fundamental frequency light and the second fundamental frequency light i 、m 2 、cos(β 1 ) 2 Different, other quantities in the formula are applicable;
in the present invention, beta is arranged between the fundamental frequency light I and the fundamental frequency light II and the seed light 1 And beta 2 Is a function of the interaction angle of (a); beta 1 An interaction angle between the fundamental frequency light and the seed light; beta 2 Is the interaction angle of the fundamental frequency light II and the seed light;
the left side of the equal sign with the addition and the subtraction is given, the right side of the equal sign is given the addition, the left side of the equal sign is given the subtraction, and the right side of the equal sign is given the subtraction;
The sign of the addition or subtraction is the propagation direction, which generally produces light in two opposite directions, positive and negative.
Where n is the refractive index of the fundamental light in the raman crystal module 7, z 0 For the displacement of fundamental frequency light between the double-light amplifying reflector 1 and the double-light amplifying reflector 2, c is the light velocity in vacuum, t is the acting time of fundamental frequency light in the Raman crystal module 7, n' is the refractive index of seed light in the Raman crystal module 7, z 0 "is the displacement of the seed light back and forth between the double-light amplifying mirror 1 and the double-light amplifying mirror 2, t" is the acting time of the seed light in the Raman crystal module 7, g 0 Raman gain coefficient g of fundamental frequency light I when collinear 1 Raman gain coefficient for the seed light;for a light intensity of the fundamental frequency light, ">For the light intensity of the fundamental frequency light in the positive direction, +.>For the light intensity of the fundamental frequency light in the negative direction, +.>For the intensity of the seed light (i.e. first order Stokes light), is>Is the light intensity of the seed light in the positive direction (i.e. first order Stokes light), the +.>Is the light intensity of the seed light (i.e. first order Stokes light) in the negative direction, +.>Is the second-order light intensity of the seed light in the positive direction (the second-order Stokes light intensity in the positive direction (i.e. the Stokes light intensity of the first order)),/the second-order seed light intensity in the positive direction>Is the second order intensity of the negative direction seed light (the second order stokes light intensity of the negative direction (i.e. the stokes light intensity of the higher order);
a 1 A is the loss coefficient of fundamental frequency light one 2 For the loss factor, K, of the seed light, i.e. first order Stokes light sp Is spontaneous Raman scattering coefficient, j 2-2 Beta is the number of times the seed light and the fundamental frequency light intersect in the raman crystal module 7 (here, the number of times the seed light and the fundamental frequency light intersect in the raman crystal module 7) 1 An interaction angle with the seed light for fundamental frequency light, wherein beta 1 =α 1 +2α 2 ,m 2 The volume coefficient is mutually coupled in the Raman crystal module 7 for seed light and fundamental frequency light, and the expression is
Wherein r is the light spot radius, b 2 The width of the second Raman crystal module 7 in the vertical direction;
it can be derived that:
when 0 is less than or equal to beta 1 M is less than 90 DEG 2 cos(β 1 ) 2 g 0 <g 0 When the seed light and the fundamental frequency light pass through the Raman crystal module 7 once, the collinear single conversion gain of the seed light and the fundamental frequency light is higher than the crossed conversion gain of the seed light and the fundamental frequency light;
when the number of intersections j 2-2 When the formula (10) is satisfied, the collinear single conversion gain of the seed light and the fundamental frequency light is the same as the crossed conversion gain of the seed light and the fundamental frequency light, and the angle beta is the same as the crossed conversion gain 1 The maximum value of the required angle is the corresponding minimum interaction times;
wherein j is 2-2 The frequency of intersection of the seed light and the fundamental frequency light in the Raman crystal;
when the angle beta 1 When further reduced, the number of intersections ji The cross conversion gain of the seed light and the fundamental frequency light is higher than the collinear single conversion gain of the seed light and the fundamental frequency light; as shown in fig. 4.
j 2-2 ×m 2 ×cos 2 β 1 The cross conversion gain of the seed light and the fundamental frequency light is smaller than the single conversion gain of a common line of the seed light and the fundamental frequency light;
j 2-2 ×m 2 ×cos 2 β 1 the cross conversion gain of the seed light and the fundamental frequency light is larger than the collinear single conversion gain of the seed light and the fundamental frequency light.
Collinear conversion gain: that is, the greater the overlapping degree, the higher the conversion efficiency in the single pass of the seed light and the fundamental frequency light through the raman crystal 7; the conversion efficiency is maximum when collinear (namely, the seed light is parallel to and coincident with the fundamental frequency light); so the superposition degree is maximum when the two parts are collinear, and the conversion efficiency is maximum; the overlapping degree is minimum to 90 degrees when the angle is crossed and overlapped, the conversion efficiency is smaller and smaller, and the conversion efficiency is 0 when the angle is 90 degrees;
cross conversion gain: conversion efficiency when the seed light and the fundamental frequency light have an intersection angle; according to the invention, the seed light and the fundamental frequency light can be periodically and repeatedly subjected to cross conversion in the Raman photonic crystal module 7 at a certain angle;
collinear single conversion gain: although the overlap volume is greatest when collinear, there is an upper saturation limit due to the increase in laser intensity, and the process and speed of this energy increase is not linearly increasing, the speed of increase being smaller as the saturation value is approached. The seed light and the fundamental frequency light are overlapped once in the Raman crystal, so that the light intensity is increased once according to the overlapped volume. The crossing angle of the seed light and the fundamental frequency light is controlled and selected, and the overlapping times in the Raman crystal are increased, so that the energy conversion effect can reach or even exceed the collinear condition.
Due to j 2-2 Is required to meet the practical significance, if j is obtained 2-2 The decimal fraction is not discarded.
Other steps and parameters are the same as in one of the first to fifth embodiments.
Seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is that the first LD pump source 8 and the second LD pump source 9 are used as excitation sources;
the double-light amplifying reflector 1 and the double-light amplifying reflector 2 form a fundamental frequency light resonant cavity;
the three elements of the laser are: excitation source, working substance and resonant cavity;
the working substances are a fundamental frequency optical crystal module I5 and a fundamental frequency optical crystal module II 6;
the first LD pump source 8 and the second LD pump source 9 horizontally output pump light to be incident to the first fundamental frequency optical crystal module 5 and the second fundamental frequency optical crystal module 6; generating fundamental frequency light II in the vertical direction of the laser, wherein the fundamental frequency light II oscillates back and forth along the vertical direction between the double-light amplifying reflector I1 and the double-light amplifying reflector II 2 and does not emit, so that the amplifying efficiency of seed light is further improved;
at this time, the mutual coupling volume coefficient of the seed light and the fundamental frequency light in the Raman crystal module 7 is m 1 =1;
When the interaction angle between the fundamental frequency light two and the seed light is shown as beta in figure 3 according to the geometrical relationship 2 =2α 2 At this time, the coupling equation is the formula (11)
Where n' is the refractive index of the fundamental light two in the raman crystal module 7, z 0 ' is the displacement of fundamental frequency light two back and forth between the double-light amplifying reflector 1 and the double-light amplifying reflector 2, c is the light velocity in vacuum, t ' is the acting time of fundamental frequency light two in the Raman crystal module 7, n ' is the refractive index of seed light in the Raman crystal module 7, z 0 "is the displacement of the seed light back and forth between the double-light amplifying mirror 1 and the double-light amplifying mirror 2, t" is the acting time of the seed light in the Raman crystal module 7, g 0 ' Raman gain coefficient of fundamental frequency light II when collinear, g 1 Raman gain coefficient for the seed light;is the two light intensities of fundamental frequency light, ">Is the two light intensities of the fundamental frequency light in the positive direction, +.>Is the two light intensities of the fundamental frequency light in the negative direction, +.>For the intensity of seed light, & lt + & gt>Is the light intensity of the seed light in the positive direction,/->Is the intensity of the seed light in the negative direction,/->Is the second order light intensity of the seed light in the positive direction, +.>The second-order light intensity of the seed light in the negative direction;
a 1 ' is the loss coefficient of fundamental frequency light two, a 2 For loss factor of seed light, K sp Is spontaneous Raman scattering coefficient, j 1-1 The crossing times of the seed light and the fundamental frequency light in the Raman crystal are obtained; beta 2 Is the interaction angle of the fundamental frequency light II and the seed light; m is m 1 The seed light and the fundamental frequency light are mutually coupled with volume coefficients in the Raman crystal module 7;
because of the sizes of the fundamental frequency optical crystal module I5 and the fundamental frequency optical crystal module II 6, the double-light amplifying reflector I1 and the double-light amplifying reflector II 2, the size of the fundamental frequency optical crystal II generated in the cavity is in a larger ellipse shape, and the long axis basically covers the long side of the Raman crystal, so that the seed light is basically and completely covered by the fundamental frequency optical crystal II in the cavity;
the left side of the equal sign with the addition and the subtraction is given, the right side of the equal sign is given the addition, the left side of the equal sign is given the subtraction, and the right side of the equal sign is given the subtraction;
the sign of the addition or subtraction is the propagation direction, which generally produces light in two opposite directions, positive and negative.
The interaction angle between the fundamental frequency light II and the seed light oscillating in the resonant cavity is beta 2 At the time, the corresponding minimum crossing times j 1-1 The method comprises the following steps:
it can be seen that under a certain power density, the seed light and the fundamental frequency light can generate cross conversion gain, beta 2 The greater the angle, the number j of interactions needed to achieve collinear single conversion gain i The larger the angle beta 2 To a certain extent, the single conversion gain is even higher than that of the second collineation of the seed light and the fundamental light.
In general, the fundamental frequency light output by the two modes of the resonant cavity consisting of the fundamental frequency light module 11, the double-light amplifying reflector I1 and the double-light amplifying reflector II 2 is subjected to energy conversion with the seed light in the Raman crystal module 7, so that the laser amplification of the seed light is realized.
Other steps and parameters are the same as in one of the first to sixth embodiments.
Eighth embodiment: this embodiment differs from one of the embodiments one to seven in that,
the first and second base frequency optical crystal modules 5 and 6 are a in size 1 ×b 1 ×c 1 mm 3
The raman crystal module 7 has a size a 2 ×b 2 ×c 2 mm 3
The first double-light magnifying reflector 1 and the second double-light magnifying reflector 2 are d in size 2 ×e 2 ×f 2 mm 3
The a 1 B is the length of the first base frequency optical crystal module 5 and the second base frequency optical crystal module 6 in the horizontal direction 1 C is the width of the first base frequency optical crystal module 5 and the second base frequency optical crystal module 6 in the vertical direction 1 A is the height of the first base frequency optical crystal module 5 and the second base frequency optical crystal module 6 2 Length of Raman crystal module II 7 in horizontal direction, b 2 C is the width of the Raman crystal module II 7 in the vertical direction 2 Height d of Raman crystal module II 7 2 Is the length of the two-light magnifying reflector I1 and the two-light magnifying reflector II 2 in the horizontal direction, e 2 Is the width of the first double-light amplifying reflector 1 and the second double-light amplifying reflector 2 in the vertical direction, f 2 The heights of the first double-light amplifying reflector 1 and the second double-light amplifying reflector 2 are set;
the crystal module can be formed by tightly attaching a plurality of crystals, and high-permeability films for fundamental frequency light, seed light and pump light are plated on the front, the back, the left and the right in the light transmission direction.
Other steps and parameters are the same as those of one of the first to seventh embodiments.
Detailed description nine: the present embodiment differs from one to eight of the specific embodiments in that the raman crystal module 7 is one of diamond, yttrium vanadate, potassium gadolinium tungstate, barium nitrate, lithium iodate, and the like.
Other steps and parameters are the same as in one to eight of the embodiments.
Detailed description ten: the difference between the present embodiment and one of the first to ninth embodiments is that the surfaces of the first and second dual-light magnifying reflectors 1 and 2 are plated with high reflection films for fundamental frequency light;
the surfaces of the first double-light amplifying reflector 1 and the second double-light amplifying reflector 2 are plated with high-reflection films for seed light;
the surface of the seed light amplifying reflector 3 is plated with a high-reflection film for seed light;
the surface of the second fundamental frequency light amplifying reflector 4 is plated with a high-reflection film for fundamental frequency light.
Other steps and parameters are the same as in one of the first to ninth embodiments.
Example 1:
in order to enable those skilled in the art to better understand the technical method of the present invention, the technical solution of the present invention will be further explained below with reference to the accompanying drawings, and based on the embodiments in the present application, other embodiments of the present invention obtained by those skilled in the art without making any creative effort should be dead within the scope of protection of the present application.
The output method of the double-light amplification Raman laser comprises the following steps:
first, the seed optical module (13) is excited to have a wavelength lambda 2 For example, a diamond crystal, a seed light wavelength lambda 2 =1240nm,λ 2 The seed light is vertically incident through the seed light coupling lens group (12) and passes through the seed light amplifying reflector I (3) to form 2 alpha 2 Angle reflection of 10 °, seed light is incident and remains with z-axis 2α 2 Angle, passing through fundamental frequency optical crystal module one (5), raman crystal module (7), fundamental frequencyA second optical crystal module (6) in which the displacement of the beam passing through the parallel plate is ignored, and the seed light reaches the second double-light amplifying reflector (2) to form 2 alpha 2 Angle reflection, the back seed light is reflected between the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) in 2 alpha 2 The angle is periodically reflected, and the seed light is horizontally moved every time 2 The distance L between the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) 2 40mm, calculate l according to equation (1) 2 =14.55 mm, and lens length d of two magnifying glass mirrors one (1) and two (2) 2 When=40 mm, the number j of reflections is calculated according to the formula (2) 2 =2.74, at this time, it can be judged that the seed light is emitted after being reflected for three periods, and the seed light is emitted in the same direction as the incident direction;
the fundamental frequency optical module (11) further excites a wavelength lambda 1 Fundamental frequency light wavelength lambda using diamond crystal as an example 1 The fundamental light is incident in the horizontal direction through the fundamental light coupling lens group (10), reflected by the fundamental light amplifying mirror (4), and kept at the z-axis alpha 1 The angle of 12 DEG is passed through the second base frequency optical crystal module (6), the Raman crystal module (7) and the first base frequency optical crystal module (5), the displacement generated by the light beam passing through the parallel flat plate is ignored, and the base frequency light reaches the first double-light amplifying reflector (1) to form alpha 1 Angle reflection, the back fundamental frequency light is alpha between the double-light amplifying reflector I (1) and the double-light amplifying reflector II (2) 1 The angle is reflected periodically, and the fundamental frequency light is moved horizontally every time 1 The distance L between the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) 2 40mm, calculate l according to equation (3) 1 =17.80 mm, and lens length d of two magnifying glass mirrors one (1) and two (2) 2 =40 mm, the number of reflections j according to equation (4) 1 The method comprises the steps of (1) and (2.24), wherein the fundamental frequency light can be emitted after being reflected for three periods, and the fundamental frequency light is emitted in the same direction as the incident direction;
the seed light and the fundamental frequency light periodically reflect and intersect between the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) as shown in FIG. 3, and beta is periodically generated 1 Angle, which satisfies the formula:
β 1 =α 1 +2α 2 =22°
therefore, in the Raman crystal module (7), the seed light periodically intersects with the fundamental frequency light to generate frequency shift, namely the frequency v of the seed light 2 =2.41*10 14 And fundamental frequency optical frequency v 1 =2.81*10 14 The formula is satisfied:
ν 2 =ν 1 -Δν
in the middle ofIs Planck constant, deltav is Raman shift generated by phonon collision of incident photon in crystal, lambda 1 Is the wavelength lambda of fundamental frequency light 2 Is the wavelength of the seed light; v (v) 2 =1/λ 2 ,ν 1 =1/λ 1
Each reflection of the seed light generates incident light and reflected light, which intersect each other, so that the actual intersection times are at least n 2 * 2=4. According to formula (10), the intersection angle is beta 1 When=22°, crystal length b 2 =7mm, spot radius 0.2mm. At this time need j 2-2 The number of intersections of =2.62≡3 times can realize that the cross conversion gain of the seed light and the fundamental frequency light is the same as the collinear single conversion gain of the seed light and the fundamental frequency light. The corresponding actual gain coefficient of the fundamental frequency light is j 2 m 2 cos(β 1 ) 2 g 0 =1.63g 0 The gain factor is increased by a factor of about 0.63 compared to the collinear single amplification mode.
The LD pump source I (8) and LD pump source II (9) shown in figure 1 are horizontally incident (1, providing energy for amplifying fundamental frequency light incident by 11; 2, can generate fundamental frequency light oscillation between 1 and 2 lenses, and the oscillation is one of amplifying the fundamental frequency light, after all, the function of the resonant cavity is also amplifying, 3, the two amplified fundamental frequency light provide energy for amplifying seed light;) and provide energy for amplifying the fundamental frequency light The oscillation and amplification provide energy, and the side pump fundamental frequency optical crystal module I (5) and the fundamental frequency optical crystal module II (6) provide energy for periodically reflecting fundamental frequency to amplify fundamental frequency light. And as the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) are plated with high-reflection films for the fundamental frequency light in the vertical direction of the z-axis, a resonant cavity for the fundamental frequency light II is formed in the vertical direction, so that the fundamental frequency light II oscillates in the direction along the z-axis. The interaction angle between the fundamental frequency light II and the seed light oscillating in the resonant cavity is beta 2 =10°, the corresponding minimum number of interactions j is obtained according to equation (12) 1-1 When=1.06≡2, the gain effect when collinear can be achieved. In practice, the incident light and the reflected light will intersect at least once each time the seed light is reflected, so the actual intersecting times are at least j 2 * 2=4, and the actual gain coefficient corresponding to the fundamental frequency light is j 2 m 1 cos(β 2 ) 2 g 0 =3.53g 0 The gain is improved by a factor of about 2.53 compared to the collinear single amplification mode.
Fundamental frequency light generated in different modes is in the Raman crystal module, so that energy is provided for the stimulated Raman scattering amplification process, and the amplification effect of seed light is improved.
Example 2:
the invention can be further expanded to change the seed light source module (13) into the seed light source module with the output wavelength lambda 4 A second order Stokes optical module (13) of which the second order Stokes wavelength lambda is exemplified by a diamond crystal 4 =1416 nm, the seed light coupling lens group (12) is changed to a second order stokes light coupling lens group (12). Fundamental frequency optical module (11) with output wavelength lambda 3 A first order Stokes optical module (11) of which the first order Stokes wavelength lambda is exemplified by a diamond crystal 3 =1240nm。
Meanwhile, the film systems of the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) are plated with high-reflection films of second-order Stokes light, first-order Stokes light and fundamental frequency light.
The seed light reflector (3) is changed into a second-order Stokes light reflector (3) which is plated with a second-order Stokes light high-reflection film.
The fundamental frequency light reflector (4) is changed into a first-order Stokes light reflector (4) which is plated with a first-order Stokes light high-reflection film.
The output method of the raman laser of the present embodiment includes the steps of:
first, the second order Stokes light module (13) excites a wavelength lambda 4 For example, a diamond crystal, a seed light wavelength lambda 4 =1416nm,λ 4 The seed light is vertically incident through a second-order Stokes optical coupling lens group (12) and is reflected by a second-order Stokes light reflecting mirror (15) at 2 alpha 2 The back seed light is incident and remains at 2 alpha to the z-axis 2 Angle, passing through the first base frequency optical crystal module (5), the Raman crystal module (7) and the second base frequency optical crystal module (6), neglecting the displacement generated by the light beam passing through the parallel flat plate, and the seed light reaches the second double-light amplifying reflector (2) to reach 2 alpha 2 Angle reflection, the seed light is reflected by 2 alpha between the two light amplifying reflectors 2 The angle is periodically reflected, and the seed light is horizontally moved every time 2 Mirror spacing L 2 40mm, calculate l according to equation (1) 2 =14.55 mm, and lens length d 2 When=40 mm, j is obtained according to the formula (2) 2 At this time, it can be determined that the seed light is emitted after three periods of reflection, and the seed light is emitted in the same direction as the incident direction.
The further first-order Stokes optical module (11) excites a wavelength lambda 3 For example, a diamond crystal, has a first order Stokes wavelength of lambda 1 The first-order Stokes light is incident in the horizontal direction through the fundamental light coupling lens group (12), reflected by the fundamental light reflecting mirror (4), and kept at the z-axis alpha 1 At an angle of 11 DEG, the first-order Stokes light passes through the second fundamental frequency optical crystal module (6), the Raman crystal module (7) and the first fundamental frequency optical crystal module (5), and the displacement generated by the light beam passing through the parallel flat plate is ignored, and the first-order Stokes light reaches the second amplifying reflector (1) to obtain alpha 1 Angle reflection, back seed light is reflected by alpha between magnifying reflectors 1 The angle is periodically reflected, and the seed light is horizontally moved every time 1 Mirror spacing L 2 40mm, calculate l according to equation (3) 1 =16.16 mm, and lens length d 2 =40 mm, according to formula (4) j 1 At this time, it can be determined that the fundamental frequency light is emitted after being reflected for three periods, and the fundamental frequency light is emitted in the same direction as the incident direction.
As before, the periodic reflection of the second order Stokes light and the first order Stokes light, as shown in FIG. 3, intersect to periodically produce beta 1 Angle, which satisfies the formula:
β 1 =α 1 +2α 2 =21°
therefore, in the Raman crystal module, the second order and the first order Stokes light periodically intersect, and frequency shift occurs, namely the second order Stokes light frequency v 4 =2.11*10 144 =1/λ 4 ) And a first order Stokes optical frequency v 3 =2.41*10 143 =1/λ 3 ) The formula is satisfied:
ν 4 =ν 3 -Δν
in the middle ofBeing the Planck constant, Δν is the Raman shift produced by phonon collisions of incident photons in the crystal. In the Raman crystal module (7), the second-order Stokes light periodically intersects with the first-order Stokes light, and Raman translation and energy conversion occur, so that the optical amplification of the second-order Stokes light is realized.
Each reflection of the seed light will be the incident light and the reflected light, the incident and emergent light will intersect, so the number of intersection times is at least j 2 * 2=4. According to formula (10), the intersection angle is beta 1 When=21°, crystal length b 2 =7mm, spot radius of 0.2mm, at least j is required 2-2 The number of intersections of =2.38≡3 times can be achieved, and the second order stokes light and the first order stokes light cross-conversion gain is the same as the second order stokes light and the first order stokes light collinear single conversion gain. The corresponding actual gain coefficient of the fundamental frequency light is j 2 m 2 cos(β 1 ) 2 g 0 =1.77g 0 The gain factor is increased by a factor of about 0.77 compared to the collinear single pass amplification mode.
The first LD pump source (8) and the second LD pump source (9) shown in fig. 1 are horizontally incident to provide energy for oscillation and amplification of fundamental frequency light, and the first side pump fundamental frequency light crystal module (5) and the second fundamental frequency light crystal module (6) provide energy for periodically reflected fundamental frequency to amplify the fundamental frequency light. And as the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) are plated with high-reflection films for 1064nm fundamental frequency light in the vertical direction of the z axis, a resonant cavity for 1064nm fundamental frequency light is formed in the vertical direction, so that the fundamental frequency light oscillates in the direction along the z axis. The interaction angle of the fundamental frequency light oscillating in the resonant cavity and the first-order Stokes light is beta 2 =10°, the corresponding minimum number of interactions j is obtained according to equation (12) 1-1 When=1.06≡2, the same gain effect can be achieved when the two are collinear. In practice, each reflection of the first-order Stokes light will be incident and reflected, and the incident and emergent light will intersect at least once, so the number of intersections is at least j 2 * 2=4, and the actual gain coefficient corresponding to the fundamental frequency light is j 2 m 1 cos(β 2 ) 2 g 0 =3.53g 0 The gain factor is improved by a factor of about 2.53 compared to the collinear single pass amplification mode.
The fundamental frequency light is arranged in the Raman crystal module to provide energy for the first-order Stokes light amplifying process, and the amplified first-order Stokes light and second-order Stokes light are arranged in the Raman crystal in beta 2 The angles are transformed in the interaction to achieve an amplified second order stokes effect.
The present invention is capable of other and further embodiments and its several details are capable of modification and variation in light of the present invention, as will be apparent to those skilled in the art, without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (10)

1. A dual amplification cavity raman laser, characterized by: the dual amplification cavity raman laser comprises: the device comprises a first double-light amplifying reflector (1), a second double-light amplifying reflector (2), a first seed light amplifying reflector (3), a second fundamental frequency light amplifying reflector (4), a first fundamental frequency light crystal module (5), a second fundamental frequency light crystal module (6), a Raman crystal module (7), a first LD pump source (8), a second LD pump source (9), a fundamental frequency light coupling lens group (10), a fundamental frequency light module (11), a seed light coupling lens group (12) and a seed light module (13);
setting a coordinate axis, wherein the x-axis direction is a horizontal direction, the z-axis direction is a vertical direction, and determining a y-axis according to a right-hand rule;
The first fundamental frequency optical crystal module (5) and the second fundamental frequency optical crystal module (6) are respectively arranged on the upper side and the lower side of the Raman crystal module (7) in the vertical direction;
the first fundamental frequency optical crystal module (5), the Raman optical crystal module (7) and the second fundamental frequency optical crystal module (6) are closely placed, so that a sandwich structure is formed;
the first LD pump source (8) and the second LD pump source (9) are respectively arranged in the horizontal directions of the first fundamental frequency optical crystal module (5) and the second fundamental frequency optical crystal module (6), the first LD pump source (8) excites pumping light to horizontally cross-enter the first fundamental frequency optical crystal module (5) along the x-axis, and the second LD pump source (9) excites pumping light to horizontally cross-enter the second fundamental frequency optical crystal module (6) along the x-axis;
in the vertical direction of the sandwich structure, a double-light amplifying reflector I (1) is arranged on a fundamental frequency optical crystal module I (5), and a double-light amplifying reflector II (2) is arranged under a fundamental frequency optical crystal module II (6);
the seed light amplifying reflector I (3) is arranged at the left side of the double light amplifying reflector I (1), and the included angle between the seed light amplifying reflector I (3) and the double light amplifying reflector I (1) is alpha 2
The fundamental frequency light amplifying reflector II (4) is arranged on the right side of the double light amplifying reflector II (2), and the included angle between the fundamental frequency light amplifying reflector II (4) and the double light amplifying reflector II (2) is as follows according to the geometric relationship α 1 The fundamental frequency light is horizontally incident and passes through the second fundamental frequency light amplifying reflector4) The reflected light is clamped with a vertical z-axis;
the seed light module (13) comprises a seed light coupling lens group (12) and a seed light source, and the seed light module (13) is arranged at the lower side of the double-light amplifying reflector II (2);
the fundamental frequency optical module (11) comprises a fundamental frequency optical coupling lens group (10) and fundamental frequency light I, and the fundamental frequency optical module (11) is arranged on one side of a fundamental frequency light amplifying reflector II (4).
2. A dual amplifying cavity raman laser according to claim 1, wherein: the seed light module (13) excites seed light, the seed light vertically enters through the seed light coupling lens group (12), after being reflected by the seed light amplifying reflector I (3), the seed light periodically reflects between the double light amplifying reflector I (1) and the double light amplifying reflector II (2), and each time the reflected seed light horizontally shifts to be:
l 2 =L 2 *tan2α 2 (1)
final number of reflections j 2 The formula is satisfied:
wherein d 2 Is the lens length L of the double-light magnifying reflector I (1) and the double-light magnifying reflector II (2) 2 Is the distance l between the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) 2 For each reflected seed light horizontal displacement, x is the multiplier; alpha 2 An included angle between the seed light amplifying reflector I (3) and the double light amplifying reflector I (1);
If j is obtained 2 The parity is directly judged for the integer;
if j is obtained 2 The decimal fraction is not discarded, and then j is judged 2 Parity of (c);
if j 2 When the number is even, the emergent direction of the seed light is opposite to the incident direction;
if j 2 When the number is odd, the emergent direction of the seed light is the same as the incident direction.
3. A dual amplifying cavity raman laser according to claim 2, wherein: the fundamental frequency light module (11) excites fundamental frequency light I, the fundamental frequency light I is horizontally incident through the fundamental frequency light coupling lens group (10), and after being reflected by the fundamental frequency light amplifying reflector II (4), periodic reflection movement is carried out between the double light amplifying reflector I (1) and the double light amplifying reflector II (2), and each time of reflection fundamental frequency light I horizontal displacement is as follows:
l 1 =L 2 *tanα 1 (3)
final number of reflections j 1 The formula is satisfied:
wherein d 2 Is the lens length L of the double-light magnifying reflector I (1) and the double-light magnifying reflector II (2) 2 Is the distance l between the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) 1 For each reflection of fundamental light a horizontal displacement alpha 1 The first fundamental frequency light horizontally enters and is reflected by the second fundamental frequency light magnifying reflector (4) and then forms an angle with the vertical z-axis;
if j is obtained 1 The parity is directly judged for the integer;
if j is obtained 1 The decimal fraction is not discarded, and then j is judged 1 Parity of (c);
if j 1 If the number is even, the outgoing direction of the fundamental frequency light is opposite to the incoming direction;
if j 1 When the number is odd, the outgoing direction of the fundamental frequency light is the same as the incoming direction.
4. A dual amplifying cavity raman laser according to claim 3, wherein: the seed light and the fundamental frequency light are periodically reflected and intersected between the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2), and an angle beta is periodically generated 1 Cross-coupling, satisfying the formula:
β 1 =α 1 +2α 2 (5)
beta in 1 Is the interaction angle between the fundamental frequency light and the seed light.
5. The dual amplifying cavity raman laser of claim 4, wherein: in the Raman crystal module (7), the seed light periodically intersects with the fundamental frequency light, and frequency translation occurs, namely the frequency v of the seed light 2 And fundamental frequency optical frequency v 1 The formula is satisfied:
in the middle ofIs Planck constant, deltav is Raman translation generated by collision of fundamental frequency light and phonons in Raman crystal module (7), lambda 1 Is the wavelength lambda of fundamental frequency light 2 Is the wavelength of the seed light; v (v) 2 =1/λ 2 ,ν 1 =1/λ 1
The fundamental frequency light is fundamental frequency light one or fundamental frequency light two.
6. The dual amplifying cavity raman laser of claim 5, wherein: the seed light and the fundamental frequency light are periodically reflected and intersected between the double-light amplifying reflector I (1) and the double-light amplifying reflector II (2), and the minimum interaction times when the collinear single conversion gain of the seed light and the fundamental frequency light is identical to the crossed conversion gain of the seed light and the fundamental frequency light are determined; the specific process is as follows:
Beta is arranged between the fundamental frequency light one and the seed light 1 Obtaining a coupling equation formula (8);
wherein n is the refractive index of the fundamental light in the Raman crystal module (7), z 0 For the displacement of fundamental frequency light back and forth between the double-light amplifying reflector I (1) and the double-light amplifying reflector II (2), c is the light velocity in vacuum, t is the acting time of fundamental frequency light in the Raman crystal module (7), n' is the refractive index of seed light in the Raman crystal module (7), and z 0 "is the displacement of the seed light back and forth between the double-light amplifying reflector I (1) and the double-light amplifying reflector II (2), t" is the acting time of the seed light in the Raman crystal module (7), g 0 Raman gain coefficient g of fundamental frequency light I when collinear 1 Raman gain coefficient for the seed light;for a light intensity of the fundamental frequency light, ">For the light intensity of the fundamental frequency light in the positive direction, +.>For the light intensity of the fundamental frequency light in the negative direction, +.>For the intensity of seed light, & lt + & gt>Is the light intensity of the seed light in the positive direction, I 1 - Is the intensity of the seed light in the negative direction,/->Is the second order light intensity of the seed light in the positive direction, +.>The second-order light intensity of the seed light in the negative direction;
a 1 a is the loss coefficient of fundamental frequency light one 2 For loss factor of seed light, K sp Is spontaneous Raman scattering coefficient, j 2-2 For the number of intersections between the seed light and the fundamental light in the Raman crystal module (7), beta 1 An interaction angle with the seed light for fundamental frequency light, wherein beta 1 =α 1 +2α 2 ,m 2 The expression is that the seed light and the fundamental frequency light are mutually coupled with volume coefficients in a Raman crystal module (7)
Wherein r is the light spot radius, b 2 The width of the second Raman crystal module (7) in the vertical direction;
when the number of intersections j 2-2 When the formula (10) is satisfied, the collinear single conversion gain of the seed light and the fundamental frequency light is the same as the crossed conversion gain of the seed light and the fundamental frequency light, and the angle beta is the same as the crossed conversion gain 1 The maximum value of the required angle is the corresponding minimum interaction times;
wherein j is 2-2 Is the number of intersections of the seed light and the fundamental light in the raman crystal.
7. The dual amplifying cavity raman laser of claim 6, wherein: the LD pump source I (8) and the LD pump source II (9) are used as excitation sources;
the double-light amplifying reflector I (1) and the double-light amplifying reflector II (2) form a fundamental frequency light resonant cavity;
the three elements of the laser are: excitation source, working substance and resonant cavity;
the working substances are a fundamental frequency optical crystal module I (5) and a fundamental frequency optical crystal module II (6);
the LD pump source I (8) and the LD pump source II (9) output pump light horizontally and transversely and are incident to the fundamental frequency optical crystal module I (5) and the fundamental frequency optical crystal module II (6); generating fundamental frequency light II in the vertical direction of the laser, wherein the fundamental frequency light II oscillates back and forth along the vertical direction between the double-light amplifying reflector I (1) and the double-light amplifying reflector II (2) and does not emit;
The mutual coupling volume coefficient of the seed light and the fundamental frequency light in the Raman crystal module (7) is m 1 =1;
When the interaction angle between the fundamental frequency light II and the seed light is beta 2 =2α 2 At this time, the coupling equation is the formula (11)
Wherein n' is the refractive index of the fundamental light two in the Raman crystal module (7), z 0 ' is the displacement of fundamental frequency light II back and forth between the double-light amplifying reflector I (1) and the double-light amplifying reflector II (2), c is the light velocity in vacuum, t ' is the acting time of fundamental frequency light II in the Raman crystal module (7), n ' is the refractive index of seed light in the Raman crystal module (7), z 0 "is the displacement of the seed light back and forth between the double-light amplifying reflector I (1) and the double-light amplifying reflector II (2), t" is the acting time of the seed light in the Raman crystal module (7), g 0 ' Raman gain coefficient of fundamental frequency light II when collinear, g 1 Raman gain coefficient for the seed light;is the two light intensities of fundamental frequency light, ">Is the two light intensities of the fundamental frequency light in the positive direction, +.>Is a negative squareLight intensity of fundamental frequency light, < >>For the intensity of the seed light,is the light intensity of the seed light in the positive direction,/->Is the intensity of the seed light in the negative direction,/->Is the second order light intensity of the seed light in the positive direction, +.>The second-order light intensity of the seed light in the negative direction;
a 1 ' is the loss coefficient of fundamental frequency light two, a 2 For loss factor of seed light, K sp Is spontaneous Raman scattering coefficient, j 1-1 The crossing times of the seed light and the fundamental frequency light in the Raman crystal are obtained; beta 2 Is the interaction angle of the fundamental frequency light II and the seed light; m is m 1 The seed light and the fundamental frequency light are mutually coupled with volume coefficients in a Raman crystal module (7);
the interaction angle between the fundamental frequency light II and the seed light oscillating in the resonant cavity is beta 2 At the time, the corresponding minimum crossing times j 1-1 The method comprises the following steps:
8. the dual amplifying cavity raman laser of claim 7, wherein: the first base frequency optical crystal module (5) and the second base frequency optical crystal module (6) are both a in size 1 ×b 1 ×c 1 mm 3
The saidThe Raman crystal module (7) has a size a 2 ×b 2 ×c 2 mm 3
The size of the double-light amplifying reflector I (1) and the double-light amplifying reflector II (2) are d 2 ×e 2 ×f 2 mm 3
The a 1 B is the length of the first base frequency optical crystal module (5) and the second base frequency optical crystal module (6) in the horizontal direction 1 Is the width in the vertical direction of the first base frequency optical crystal module (5) and the second base frequency optical crystal module (6), c 1 A is the height of the first base frequency optical crystal module (5) and the second base frequency optical crystal module (6) 2 Length of Raman crystal module II (7) in horizontal direction, b 2 C is the width of the Raman crystal module II (7) in the vertical direction 2 Is the height, d, of the Raman crystal module II (7) 2 Is the length of the two light amplifying reflection mirrors I (1) and II (2) in the horizontal direction, e 2 Is the width of the dual-light magnifying reflector I (1) and the dual-light magnifying reflector II (2) in the vertical direction, f 2 The height of the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2).
9. The dual amplifying cavity raman laser of claim 8, wherein: the Raman crystal module (7) is one of diamond, yttrium vanadate, potassium gadolinium tungstate, barium nitrate and lithium iodate.
10. The dual amplifying cavity raman laser of claim 9, wherein: the surfaces of the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) are plated with high-reflection films for fundamental frequency light;
the surfaces of the first double-light amplifying reflector (1) and the second double-light amplifying reflector (2) are plated with high-reflectivity films for seed light;
the surface of the seed light amplifying reflector I (3) is plated with a high-reflection film for seed light;
the surface of the second fundamental frequency light amplifying reflector (4) is plated with a high-reflection film for fundamental frequency light.
CN202310711108.0A 2023-06-15 2023-06-15 Double-amplification inner cavity Raman laser Pending CN116505356A (en)

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CN116505356A true CN116505356A (en) 2023-07-28

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