CN115061286A - Spectrum beam combining device and method - Google Patents
Spectrum beam combining device and method Download PDFInfo
- Publication number
- CN115061286A CN115061286A CN202210845048.7A CN202210845048A CN115061286A CN 115061286 A CN115061286 A CN 115061286A CN 202210845048 A CN202210845048 A CN 202210845048A CN 115061286 A CN115061286 A CN 115061286A
- Authority
- CN
- China
- Prior art keywords
- laser
- grating
- transmission
- diffraction
- beam combining
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/1086—Beam splitting or combining systems operating by diffraction only
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
- Semiconductor Lasers (AREA)
Abstract
The invention relates to the technical field of laser, in particular to a spectrum beam combining device and a method, wherein the spectrum beam combining device comprises a laser unit array, a conversion lens, a reflection grating and a transmission grating; one reflection grating is provided; the number of the transmission gratings is N, and N is an integer greater than or equal to one; the laser unit array comprises laser units, the laser units output laser beams, the laser beams are subjected to the action of a conversion lens, are incident to the transmission grating at different angles, and are incident to the reflection grating after being diffracted by the transmission grating; and the laser beam is output after being subjected to multiple diffraction by the transmission grating and the reflection grating. The spectrum beam combining device can realize effective beam combination under the condition of not using an external cavity mirror, and simultaneously can improve the dispersion capability of the dispersion element by (2N +1) times through position conversion and light path design, thereby reducing the spectrum width of the spectrum combined beam by (2N +1) times and being beneficial to expanding the application occasion of the spectrum beam combining light source.
Description
Technical Field
The invention relates to the technical field of laser, in particular to a dense spectrum beam combining device and method for a reusable transflective grating.
Background
The spectral beam combining technology is one of the most feasible technologies for realizing high-power and high-beam-quality combined laser at present. From the 1999 report, the technology has been successfully applied to all-solid-state lasers, fiber lasers and semiconductor lasers, and the performance of the lasers is greatly improved.
Basic principles and methods of spectral beam combining: based on optical elements with dispersion capacity, such as gratings, prisms and the like, a plurality of unit laser beams with different lasing wavelengths are arranged according to a certain rule, and the unit laser beams output combined laser in a mode of overlapping a near field and a far field through dispersion of a dispersion element, wherein the obtained combined laser beam has power which is the sum of all the unit laser beams, and the beam quality is similar to that of the unit laser beams, so that the combined laser output with high power and high beam quality is realized.
From the above principle, when the power and the beam quality of the laser are improved, the spectrum of the combined laser is also the superposition of the spectra of all the laser units, and since each laser unit has different central wavelengths (necessary conditions for realizing the spectrum combination), the spectrum of the combined laser is widened and is larger than the spectrum width of the laser unit. On one hand, the method is difficult to be applied to occasions with strict requirements on the spectrum width; on the other hand, the combined beam performance improvement for a nominal bandwidth is limited.
In the process of combining the light beams by spectrum, how to improve the dispersion capability of the dispersion element becomes critical. The existing spectrum beam combination structure generally adopts a single grating or single diffraction, the principle of grating diffraction is known, the dispersion capability can be realized by adopting high-order diffraction or by reducing the grating constant, in order to realize high-efficiency diffraction, the existing spectrum beam combination adopts gratings of one order or negative one order, and the high dispersion cannot be realized by adopting high-order diffraction, so that the dispersion is improved mainly by reducing the grating constant and increasing the number of lines in unit size. The dispersion capacity can be improved to a certain extent by increasing the number of lines per millimeter, but the diffraction angle is increased, the effective sectional area of the grating is reduced, and the problems of difficulty or cost of spectrum beam combination and the like are aggravated. For example, when the diffraction angle is greater than 65 °, it becomes very difficult to adjust the optical path, and therefore the diffraction angle of the currently used grating is generally less than 65 °, which also results in difficulty in improving the grating dispersion capability by the number of lines.
The publication No. CN 107272214B and the document Narrow-beam combining with a nonparallel double-collimating structure (Chinese Optics Letters,2017,15(9):091403) propose to use a device for realizing semiconductor laser spectrum beam combining by using double gratings, through the superposition of the double gratings, the dispersion capability of the dispersion element can be improved by 2 times, under the condition that the laser cavity length is not changed, the laser spectrum broadening can be shortened to the original half, in the gain curve of the semiconductor laser, and in the wavelength range of the high diffraction efficiency of the gratings, the number of beam combining units can be improved by one time, and the power and the brightness can be improved by one time; the publication numbers are CN107240856B and CN107240856B, and the documents Narrow-wavelength-spread spectral combining laser with a reflector for a double pass with a single grating (Chinese Optics Letters,2018,16(7):071402) propose a spectrum beam combining device which utilizes the grating and the reflecting element to realize twice diffraction and compression of the spectral width, utilizes the reflecting element to reflect the incident beam, realizes the second dispersion twice through the diffraction action of the grating, improves the diffraction capability of the grating by one time, compresses the spectral width of the output laser by half, and equivalently achieves the dispersion capability as same as the double grating superposition.
From the above, the dispersion capability can be further improved by superimposing more gratings. However, according to the above method, if the dispersion capability needs to be further improved, the number of devices and the cost are increased, and the difficulty of tuning is further increased. However, the optical path becomes complicated, the adjustment is not easy, and the cost is increased.
Disclosure of Invention
In order to solve the above problems, the present invention provides a spectrum beam combining device and method for multiplexing a reflection grating and a transmission grating by superimposing N transmission gratings and one reflection grating, thereby significantly improving the overall dispersion capability.
The invention provides a spectrum beam combining device, which comprises a laser unit array, a conversion lens, a reflection grating and a transmission grating, wherein the laser unit array is arranged on the front surface of a light source; the number of the reflection gratings is one; the number of the transmission gratings is N, and N is an integer greater than or equal to one;
the laser unit array comprises a laser unit, the laser unit outputs laser beams, the laser beams are acted by the conversion lens, are incident to the transmission grating at different angles, are diffracted by the transmission grating and then are incident to the reflection grating; and the laser beam is output after being subjected to multiple diffraction by the transmission grating and the reflection grating.
Preferably, the laser unit array includes a first laser unit disposed in a middle position, and a second laser unit and a third laser unit respectively symmetrically disposed at two sides of the first laser unit.
Preferably, through setting of the output wavelength and the spatial position of the laser unit, the diffraction angle of the second diffraction of the laser beam output by each laser unit on the transmission grating is the same, and the laser beam output by each laser unit intersects with a point on the transmission grating during the second diffraction on the transmission grating under the common diffraction action of the transformation lens, the reflection grating and the transmission grating.
Preferably, the spectrum beam combining device further comprises an external cavity mirror, and the laser beam is output to the external cavity mirror after being diffracted for multiple times by the transmission grating and the reflection grating.
Preferably, adjacent transmission gratings are not parallel to each other.
Preferably, the reflection grating is a first-order diffraction grating, the first-order diffraction efficiency of the reflection grating is greater than 90%, and the diffraction polarization direction of the reflection grating is matched with the polarization direction of the laser beam.
Preferably, the transmission grating is a negative first-order diffraction grating, the negative first-order diffraction efficiency of the transmission grating is greater than 90%, and the diffraction polarization direction of the transmission grating is matched with the polarization direction of the laser beam.
Preferably, the laser unit array includes a laser unit, the laser unit includes a laser device and an optical element, the optical element performs at least one of collimation, shaping and polarization direction adjustment on a laser beam output by the laser device, and an antireflection film is plated on an end face of the laser device, where the laser beam is output by the laser device.
Preferably, the laser device is a semiconductor laser, a fiber laser or an all-solid-state laser.
The invention also provides a spectrum beam combining method, which is realized by the spectrum beam combining device and comprises the following steps:
s1, outputting a laser beam by the laser unit array;
s2, the laser beam passes through the transformation lens to be incident to the transmission grating at different angles,
s3, after the laser grating is diffracted by the transmission grating, the laser grating is incident to the reflection grating for diffraction;
s4, outputting the laser beam to the external cavity mirror after the laser beam is subjected to multiple diffraction by the transmission grating and the reflection grating
The dense spectrum beam combining device and the dense spectrum beam combining method for the multiplexing transmission and reflection grating can realize effective beam combining without using an external cavity mirror, and simultaneously can improve the dispersion capability of a dispersion element by (2N +1) times through position conversion and light path design, so that the spectrum beam combining width of the spectrum is reduced by (2N +1) times, and the application occasion of a spectrum beam combining light source is favorably expanded.
Drawings
Fig. 1 is a schematic structural diagram of a spectrum beam combining device according to a first embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a spectrum beam combining device according to a second embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a spectral beam combining device according to a third embodiment of the present invention.
FIG. 4 is a schematic diagram of a structure with different wavelength outputs implemented by different period grating modulation
Fig. 5 is a schematic structural diagram of external grating feedback with different periods to realize different wavelength outputs.
Fig. 6 is a schematic structural diagram of a spectral beam combining device of a comparative example in the prior art.
FIG. 7 is a schematic diagram showing an absorption spectrum of a gain fiber in a comparative example in the prior art.
Reference numerals
10. The laser unit array comprises a laser unit array 100, a first laser unit 101, a second laser unit 102, a third laser unit 1001, a first laser beam 12, a laser chip 20, a conversion lens 30, a transmission grating 301, a first transmission grating 302, a second transmission grating 303, a second transmission grating 30N, an Nth transmission grating 40, a reflection grating 50 and an external cavity mirror.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.
The invention provides a spectrum beam combining device, which comprises a laser unit array, a conversion lens, a reflection grating and a transmission grating; the number of the reflection gratings is one; the number of the transmission gratings is N, and N is an integer greater than or equal to one;
the laser unit array comprises a laser unit, the laser unit outputs laser beams, the laser beams are acted by the conversion lens, are incident to the transmission grating at different angles, are diffracted by the transmission grating and then are incident to the reflection grating; and the laser beam is output after being subjected to multiple diffraction by the transmission grating and the reflection grating. In a specific embodiment, the laser unit array includes a plurality of laser units, and the more laser units participating in beam combination, the higher power can be obtained; in a preferred embodiment, the number of laser units in the laser unit array is such that the gain spectrum of the laser units matches the external cavity feedback wavelength and can resonate to the external cavity locking wavelength.
The dense spectrum beam combining device and the dense spectrum beam combining method for the multiplexing transmission and reflection grating can realize effective beam combining without using an external cavity mirror, and simultaneously can improve the dispersion capability of a dispersion element by (2N +1) times through position conversion and light path design, so that the spectrum beam combining width of the spectrum is reduced by (2N +1) times, and the application occasion of a spectrum beam combining light source is favorably expanded. In other embodiments, the spectral beam combining device of the present invention can also achieve effective beam combining in the case of including an external cavity mirror by the cooperation of one reflection grating and one or more transmission gratings.
As shown in fig. 1, a schematic structural diagram of a spectral beam combining device according to a first embodiment of the present invention is shown, in this embodiment, the spectral beam combining device includes a laser unit array 10, a transforming lens 20, a reflection grating 40, a transmission grating 30, and an external cavity mirror 50, where the external cavity mirror is equivalent to a cavity mirror of a laser resonator, and a planar mirror may be used, so that only light that is perpendicularly incident on the external cavity mirror 50 and can return to the laser unit along the original path can resonate, and laser light that is not perpendicularly incident on the external cavity mirror 50 cannot resonate but is lost, and finally, laser beams that are perpendicularly incident on the external cavity mirror 50 remain.
Specifically, in a manner of using one (i.e. one) transmission grating 30 and one (i.e. one) reflection grating 40, the laser unit array 10 includes a first laser unit 100 disposed at a middle position, and a second laser unit 101 and a third laser unit 102 symmetrically disposed at two sides of the first laser unit 100, respectively. Specifically, the second laser unit 101, the first laser unit 100, and the third laser unit 102 arranged along the spectrum beam combining direction (x) output laser along the same direction (z), wherein the output light of the first laser unit 100 at the central position is a principal light 1001, and the second laser unit 101 and the third laser unit 102 are distributed on two sides of the first laser unit 100. The laser beams output by the laser units are acted by the conversion lens 20 and then enter the transmission grating 30 at different angles, the incident angle of a chief ray 1001 on the transmission grating 30 is the littrow angle of the transmission grating 30, the chief ray is diffracted by the transmission grating 30 and then further enters the reflection grating 40, a certain difference exists between the incident angle of the chief ray 1001 on the reflection grating 40 and the littrow angle of the reflection grating 40, the angle difference is less than +/-5 degrees, the chief ray is then diffracted by the reflection grating 40 and then further enters the transmission grating 30, the laser beams output by the second laser unit 101, the first laser unit 100 and the third laser unit 102 are superposed on the transmission grating 30, and finally are diffracted out by the transmission grating 30 and then enter the external cavity mirror 50, only the chief ray vertically enters the external cavity mirror 50 and is reflected, and the beams returning to the original laser units can form resonance, the same diffraction angle and different incidence angle effects on the transmission grating 30 and the reflection grating 40 cause each laser unit to resonate at different wavelength values. In the whole resonant cavity light path, 2 times of light passes through the transmission grating 30 and 1 time of light passes through the reflection grating 40, diffraction capacity is superposed for 3 times, so that the integral dispersion capacity of the dispersion element is improved by 3 times, the incident angle delta theta of a laser beam at the grating is not changed and is the same as that of a single grating, and the integral spectral width can be compressed to 1/3 of the single grating structure according to the grating diffraction theory.
In a specific embodiment, the laser unit array 10 includes a laser unit, the laser unit includes a laser device and an optical element, the optical element performs at least one of collimation, shaping, or polarization direction adjustment on a laser beam output by the laser device, and an antireflection film is plated on an end face of the laser device, where the laser beam is output; the laser device is a semiconductor laser, a fiber laser or an all-solid-state laser.
In a specific embodiment, the transmission grating 30 is a negative first-order diffraction grating, the negative first-order diffraction efficiency of the transmission grating 30 is greater than 90%, and the grating efficient diffraction polarization direction of the transmission grating 30 matches the polarization direction of the laser beam. In other embodiments, the number of the transmission gratings is two or more, and if the transmission grating 30 is a plurality of pieces, that is, a combination of a plurality of negative first-order diffraction gratings, the negative first-order diffraction efficiency is greater than 90%, adjacent transmission gratings are not parallel to each other, and both the incident angle and the diffraction angle formed by the principal ray 1001 and the transmission grating 30 are littrow angles. The reflection grating 40 is a first-order diffraction grating, the first-order diffraction efficiency of the reflection grating is more than 90%, and the efficient diffraction polarization direction of the grating of the reflection grating 40 is matched with the polarization direction of the laser beam; the transmission grating 30 and the reflection grating 40 may have the same grating constant or different grating constants.
Fig. 2 is a schematic structural diagram of a spectrum beam combining device according to a second embodiment of the present invention, in this embodiment, the spectrum beam combining device includes a laser unit array 10, a transforming lens 20, a reflection grating 40, a transmission grating 30 and an external cavity mirror 50, specifically, a mode of combining N pieces of transmission gratings 30 and one piece of reflection grating 40 is adopted, and the rest is basically the same as the first embodiment; the resonant cavity of the whole laser consists of the back cavity surface of the laser unit and an external cavity mirror (50), and in each embodiment, the front cavity surface of the laser unit is plated with a high anti-reflection film, and the back cavity surface is plated with a high anti-reflection film. The lasing wavelength of each laser unit is determined by the position of the intracavity optics and the laser unit.
The second laser unit 101, the first laser unit 100, and the third laser unit 102 arranged along the spectrum beam combining direction (x) output laser along the same direction (z), wherein the first laser unit 100 at the center outputs a main light ray 1001, and the second laser unit 101 and the third laser unit 102 are distributed on two sides of the first laser unit 100. For the sake of clarity, only the transmission process of the chief ray 1001 is illustrated in the figure. The laser beams output by the laser units are acted by the conversion lens 20 and then sequentially enter the first transmission grating 301, the second transmission grating 302, the third transmission grating 303 … … and the Nth transmission grating 30N, all the transmission gratings are not parallel, the incident angle and the diffraction angle of the laser beams on each transmission grating 30 are close to the littrow angle, the light diffracted by the Nth transmission grating 30N further enters the reflection grating 40 and then is transmitted reversely after being diffracted by the reflection grating 40, the included angle between the incident light and the diffraction light of the reflection grating 40 is less than 10 degrees, the diffraction light then sequentially enters the Nth transmission grating 30N … …, the third transmission grating 303, the second transmission grating 302 and the first transmission grating 301, and finally the laser beams output by all the laser units are emitted to the same position of the first transmission grating 301 and then are output along the diffraction direction of the first transmission grating 301, and is incident on the external cavity mirror 50, only light that is perpendicularly incident on the external cavity mirror 50 and can return to the laser unit along the original path can be effectively resonated. All laser units resonate to different laser wavelengths under the combined action of external cavity feedback and an intra-cavity device, wherein the external cavity feedback refers to effective resonant laser formed by the external cavity mirror 50, and only light beams which vertically enter the external cavity mirror 50 and can be fed back to the original laser units can resonate the effective resonant light to generate light amplification to form laser emission; the intracavity device generally refers to all elements contained within a resonant cavity formed by the back facet of the laser chip 12 and the external cavity mirror 50, and thus includes the gain medium of the laser chip 12, the conversion lens 20, the transmission grating 30, and various collimation shaping optical elements. If the grating constants of all the transmission gratings 30 and the reflection gratings 40 are consistent and the dispersion capacities are the same, the laser beams output from the laser units undergo diffraction for (2N +1) times in the process of reaching the external cavity mirror 50, the integral dispersion capacity is (2N +1) times of the dispersion capacity of a single grating, and compared with a single-grating spectrum combining structure, the spectrum width output by the spectrum combining device structure of the embodiment is 1/(2N +1) of the spectrum width, and the spectrum line width is effectively compressed.
The embodiment provides the multiplexing of N transmission gratings and 1 reflection grating, and through position conversion and light path design, the dispersion capacity of the dispersion element can be improved by (2N +1) times, so that the spectrum width of the spectrum combined beam is reduced by (2N +1) times, and the application occasion of the spectrum combined beam source is favorably expanded. In addition, the laser transmitted in the forward direction is folded to the direction of the laser unit to be transmitted by introducing the reflection grating, and the light path is folded, so that the geometric dimension of the whole light source can be reduced to a certain extent, the miniaturization of the light source is favorably realized, and the engineering application is facilitated.
As shown in fig. 3, a schematic structural diagram of a spectral beam combining device according to a third embodiment of the present invention is shown, in which the spectral beam combining device includes a laser unit array 10, a transforming lens 20, a reflection grating 40, and a transmission grating 30, and is substantially the same as the first embodiment except that an external cavity mirror 50 is not used. The difference is that each laser unit on the laser unit array 10 realizes laser output with different wavelengths through a chip etching grating or an external cavity feedback locking wavelength, and feedback adjustment through a following optical element is not needed. To achieve good beam quality, the output wavelength (λ) of each laser unit is required 0 、λ 1 、λ 2 ) And the spatial position must be such that the second diffraction on the transmission grating 30 has the same diffraction angle and the laser beams output from the respective laser units intersect at a point, thereby realizing the combined beam output in a manner of overlapping the near field and the far field. Specifically, as shown in fig. 4 and 5, the structure diagrams of different wavelength outputs by modulating the built-in different period gratings and the structure diagrams of different wavelength outputs by feeding back the external different period gratings are respectively shown; as can be seen from the figure, in order to realize the combined output of the laser beams in such a manner that the near field and the far field overlap, the output wavelength (λ) of each laser unit is required 0 、λ 1 、λ 2 ) And the spatial position must satisfy the same diffraction angle of the second diffraction on the transmission grating 30, and the laser beams output by each laser unit intersect at a point under the common diffraction action of the transformation lens 20, the reflection grating 40 and the transmission grating 30, so that the effective beam combination can still be realized by the scheme of the embodiment without the need of the external cavity mirror 50.
In a specific embodiment of the present invention, a spectrum combining method is further provided, where the spectrum combining method includes the steps of:
s1, outputting laser beams by the laser unit array;
s2, the laser beam passes through the transformation lens to be incident to the transmission grating at different angles,
s3, after the laser grating is diffracted by the transmission grating, the laser grating is incident to the reflection grating for diffraction;
and S4, outputting the laser beam after multiple diffractions through the transmission grating and the reflection grating.
According to the different implementation modes, the dense spectrum beam combining device and the dense spectrum beam combining method for the multiplexing transmission and reflection grating can realize effective beam combining without using an external cavity mirror, and simultaneously can improve the dispersion capability of a dispersion element by (2N +1) times through position conversion and light path design, so that the spectrum beam combining width of the spectrum is reduced by (2N +1) times, and the application occasion of a spectrum beam combining light source is favorably expanded.
The following is a further description with reference to specific comparative examples and examples.
Comparative example
Fig. 6 is a schematic structural view of a spectrum beam combining device of a comparative example in the prior art, and in particular is a schematic structural view of spectrum beam combining performed based on a single transmission grating, where 12 is a laser chip, a plurality of laser units are arranged in a spectrum beam combining direction (x) and are emitted in the same direction (z), a high antireflection film is coated on a front cavity surface of each laser unit, after the laser units are affected by a conversion lens 20, all unit light beams are converged on the transmission grating 30, and after the laser units are diffracted by the transmission grating 30, the diffracted light is output to an external cavity mirror 50, in order to achieve high diffraction efficiency, an incident angle and a diffraction angle of an optical axis (generally, the emitting direction of the laser unit in the middle position, and the laser unit in the position 0 in the figure) of the combined light beam on the grating are equal to a littrow angle of the transmission grating 50, and laser units (-9 to-1, 1 to 9) on two sides have different incident angles and the same diffraction angle on the grating, the external cavity mirror 50 has a certain reflectivity, perpendicular to the littrow angular diffraction direction of the transmission grating 30. Only the light beam which is vertically incident to the external cavity mirror 50 and reflected by the external cavity mirror 50 and can return to the emergent laser unit can form effective seed light for oscillation starting, the light beam which cannot be fed back to the emergent laser unit is cut off or lost, and each laser unit resonates at different wavelengths because the grating incidence angle of each resonant unit is different and the diffraction angle is the same.
Taking a 976nm semiconductor laser for fiber pumping as an example, fig. 7 is a schematic diagram of an absorption spectrum of a Yb gain fiber in the comparative example, and it can be seen from the diagram that two curves in the diagram represent absorption light and emission light respectively, there is an absorption peak at a 976nm position and drops sharply to both sides, and the full width at half maximum is about 4nm, in order to achieve good pumping effect, it is required that the output wavelength of the 976nm laser is also within the absorption spectrum range, i.e. the central wavelength is 976nm, the overall spectrum width is less than 4nm, and the smaller the overall spectrum width is, the better.
By taking a standard centimeter strip with 19 built-in laser units as a spectrum beam combining unit for example, the width of a unit light emitting area is 100 micrometers, the period interval is 500 micrometers, an antireflection film is plated on a front cavity surface, the transmittance is greater than 99.5%, TE linearly polarized light is adopted, the focal length of an adopted conversion lens 20 is 300mm, the grating constant of a transmission grating 30 is 625nm, the number of lines is 1600 lines/mm, the littrow angle for a laser with the wavelength of 976nm is 51.33 degrees, the dispersion is 2.56mrad/nm, and the diffraction efficiency for S polarized light is more than 95%.
In this comparative example, the conventional spectral beam combining structure of the monolithic grating is used for spectral beam combining, the incident angle and the diffraction angle at the transmission grating 30 are both 51.33 °, according to the spectral beam combining principle, the central resonance wavelength of 19 laser units is shown in table 1, the central resonance wavelength is 976nm, the maximum resonance wavelength is 981.80nm, the shortest wavelength is 970.09nm, the whole bandwidth is 11.71nm, which is much larger than the 4nm requirement required by fiber pumping, so the light source cannot be used for fiber laser pumping.
TABLE 1 resonance center wavelength of conventional spectral beam combining structure
Example 1
Based on the principle shown in fig. 4, the structure of the spectral beam combining device of the present invention is specifically illustrated by using one transmission grating 30 and one reflection grating 40, where the number of lines of the transmission grating 30 and the reflection grating 40 is also 1600 lines/mm, multiple diffractions are performed according to the method shown in fig. 2, the angle and the diffraction angle of the first incident light to the transmission grating 30 are both 51.33 °, the incident angle of the laser beam diffracted by the transmission grating 30 to the reflection grating 40 is 48 °, the diffraction light of the reflection grating 40 with the diffraction angle of 54.99 ° returns to the transmission grating 30, the incident angle to the transmission grating 30 is 58.32 °, the corresponding diffraction angle is 45.33 °, and in order to achieve high diffraction efficiency, under the condition of sufficient spatial position, the incident angles and the diffraction angles of all gratings are as close to the littrow angle as much as possible, and the included angle 304 between the two gratings is 3.33 °; and the center wavelength can be finely adjusted to a desired value by adjusting the angle of the external cavity mirror 50. According to a grating diffraction equation, the central wavelength corresponding to each unit is shown in table 2, the central resonance wavelength is still 976nm, the maximum resonance wavelength is 977.93nm, the shortest wavelength is 974.03nm, the whole bandwidth is 3.90nm, the spectral width is effectively compressed by 3 times, and the requirement of 4nm required by optical fiber pumping is met, so that the light source can be used for optical fiber laser pumping, and the application of a spectral beam combining light source is expanded.
TABLE 2 example resonant center wavelength of spectral beam combining structure
Example 2
On the basis of embodiment 1, the number of the transmission gratings 30 is increased, and if the number of the transmission gratings is increased to 5, the overall dispersion capacity is increased by 11 times, the corresponding combined beam spectral width can be compressed to 1.06nm, the number of units can be increased by 2.7 times within the 4nm bandwidth, and the laser power can be further increased under the condition of meeting the spectral requirement.
While embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be taken as limiting the invention. Variations, modifications, substitutions and alterations of the above-described embodiments may be made by those of ordinary skill in the art without departing from the scope of the present invention.
The above embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. A spectrum beam combining device is characterized by comprising a laser unit array, a conversion lens, a reflection grating and a transmission grating; the number of the reflection gratings is one; the number of the transmission gratings is N, and N is an integer greater than or equal to one;
the laser unit array comprises laser units, the laser units output laser beams, the laser beams are subjected to the action of the transformation lens, enter the transmission grating at different angles, are diffracted by the transmission grating and then enter the reflection grating; and the laser beam is output after being subjected to multiple diffraction by the transmission grating and the reflection grating.
2. The spectral beam combining device of claim 1 wherein the array of laser units comprises a first laser unit disposed at a middle position, and a second laser unit and a third laser unit disposed symmetrically at two sides of the first laser unit, respectively.
3. The spectral beam combining device of claim 1, wherein the diffraction angle of the second diffraction of the laser beam outputted by each laser unit on the transmission grating is the same through the arrangement of the output wavelength and the spatial position of the laser unit, and the laser beam outputted by each laser unit intersects with a point on the transmission grating during the second diffraction on the transmission grating under the common diffraction action of the transforming lens, the reflection grating and the transmission grating.
4. The spectral beam combining device of claim 1 further comprising an external cavity mirror, wherein the laser beam is output to the external cavity mirror after being diffracted by the transmission grating and the reflection grating for a plurality of times.
5. The spectral combining apparatus of claim 1, wherein adjacent transmission gratings are not parallel to each other.
6. The spectral beam combining apparatus of claim 1 wherein the reflection grating is a first order diffraction grating, the first order diffraction efficiency of the reflection grating is greater than 90%, and the diffraction polarization direction of the reflection grating matches the polarization direction of the laser beam.
7. The spectral beam combining device of claim 1 wherein the transmission grating is a negative first order diffraction grating, the negative first order diffraction efficiency of the transmission grating is greater than 90%, and the diffraction polarization direction of the transmission grating matches the polarization direction of the laser beam.
8. The spectral beam combining apparatus of claim 1 wherein the array of laser units comprises laser units, the laser units comprising laser devices and optical elements, the optical elements at least one of collimating, shaping, or polarization direction adjusting the laser beams output by the laser devices, the laser devices being coated with an anti-reflective coating on the end faces from which the laser beams are output.
9. The spectral combining apparatus of claim 8, wherein the laser device is a semiconductor laser, a fiber laser, or an all-solid-state laser.
10. A spectral beam combining method implemented by the spectral beam combining device according to any one of claims 1 to 9, the spectral beam combining method comprising the steps of:
s1, outputting laser beams by the laser unit array;
s2, the laser beam passes through the transformation lens to be incident to the transmission grating at different angles,
s3, after the laser grating is diffracted by the transmission grating, the laser grating is incident to the reflection grating for diffraction;
and S4, outputting the laser beam after multiple diffractions through the transmission grating and the reflection grating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210845048.7A CN115061286B (en) | 2022-07-19 | 2022-07-19 | Spectrum beam combining device and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210845048.7A CN115061286B (en) | 2022-07-19 | 2022-07-19 | Spectrum beam combining device and method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115061286A true CN115061286A (en) | 2022-09-16 |
| CN115061286B CN115061286B (en) | 2023-08-22 |
Family
ID=83207045
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210845048.7A Active CN115061286B (en) | 2022-07-19 | 2022-07-19 | Spectrum beam combining device and method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115061286B (en) |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104332821A (en) * | 2014-11-18 | 2015-02-04 | 中国工程物理研究院应用电子学研究所 | Diode laser spectrum synthesizer based on double-grating external cavity feedback |
| CN105811245A (en) * | 2016-05-18 | 2016-07-27 | 上海高意激光技术有限公司 | Laser array beam combining device |
| CN107272214A (en) * | 2017-07-05 | 2017-10-20 | 中国科学院上海光学精密机械研究所 | The spectrum beam combination device of the spectrum width of diffraction compression twice is realized using grating and reflecting element |
| CN108321677A (en) * | 2018-04-28 | 2018-07-24 | 上海高意激光技术有限公司 | A kind of semiconductor laser beam merging apparatus |
| CN108429129A (en) * | 2018-05-08 | 2018-08-21 | 中国科学院半导体研究所 | The conjunction beam system and method for multi-thread array semiconductor laser grating external-cavity spectrum |
| CN109560458A (en) * | 2019-02-15 | 2019-04-02 | 上海高意激光技术有限公司 | Semiconductor laser spectrum beam combination frequency doubling device |
| CN110109259A (en) * | 2019-04-25 | 2019-08-09 | 中国科学院苏州生物医学工程技术研究所 | The beam merging apparatus of semiconductor laser high light beam quality high-power output |
| CN209946540U (en) * | 2019-04-25 | 2020-01-14 | 中国科学院苏州生物医学工程技术研究所 | Beam combiner for high beam quality and high power output of semiconductor laser |
| KR102076109B1 (en) * | 2019-10-08 | 2020-02-11 | 주식회사 한화 | Fiber array structure for spectral beam combining system and dual-grating spectral beam combining system using the same |
| CN110908129A (en) * | 2019-11-29 | 2020-03-24 | 中国科学院长春光学精密机械与物理研究所 | Beam combining optical device |
| CN110989182A (en) * | 2019-11-29 | 2020-04-10 | 中国科学院长春光学精密机械与物理研究所 | Beam combination light source device |
| CN111221136A (en) * | 2019-11-29 | 2020-06-02 | 中国科学院长春光学精密机械与物理研究所 | Beam combining optical device |
-
2022
- 2022-07-19 CN CN202210845048.7A patent/CN115061286B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104332821A (en) * | 2014-11-18 | 2015-02-04 | 中国工程物理研究院应用电子学研究所 | Diode laser spectrum synthesizer based on double-grating external cavity feedback |
| CN105811245A (en) * | 2016-05-18 | 2016-07-27 | 上海高意激光技术有限公司 | Laser array beam combining device |
| CN107272214A (en) * | 2017-07-05 | 2017-10-20 | 中国科学院上海光学精密机械研究所 | The spectrum beam combination device of the spectrum width of diffraction compression twice is realized using grating and reflecting element |
| CN108321677A (en) * | 2018-04-28 | 2018-07-24 | 上海高意激光技术有限公司 | A kind of semiconductor laser beam merging apparatus |
| CN108429129A (en) * | 2018-05-08 | 2018-08-21 | 中国科学院半导体研究所 | The conjunction beam system and method for multi-thread array semiconductor laser grating external-cavity spectrum |
| CN109560458A (en) * | 2019-02-15 | 2019-04-02 | 上海高意激光技术有限公司 | Semiconductor laser spectrum beam combination frequency doubling device |
| CN110109259A (en) * | 2019-04-25 | 2019-08-09 | 中国科学院苏州生物医学工程技术研究所 | The beam merging apparatus of semiconductor laser high light beam quality high-power output |
| CN209946540U (en) * | 2019-04-25 | 2020-01-14 | 中国科学院苏州生物医学工程技术研究所 | Beam combiner for high beam quality and high power output of semiconductor laser |
| KR102076109B1 (en) * | 2019-10-08 | 2020-02-11 | 주식회사 한화 | Fiber array structure for spectral beam combining system and dual-grating spectral beam combining system using the same |
| CN110908129A (en) * | 2019-11-29 | 2020-03-24 | 中国科学院长春光学精密机械与物理研究所 | Beam combining optical device |
| CN110989182A (en) * | 2019-11-29 | 2020-04-10 | 中国科学院长春光学精密机械与物理研究所 | Beam combination light source device |
| CN111221136A (en) * | 2019-11-29 | 2020-06-02 | 中国科学院长春光学精密机械与物理研究所 | Beam combining optical device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115061286B (en) | 2023-08-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10205295B2 (en) | Chirped Bragg grating elements | |
| CN107240856B (en) | The spectrum beam combination device of diffraction twice is realized using the transmission grating of plating reflectance coating | |
| US8537865B1 (en) | Fiber-laser pumped by stabilized diode-laser bar stack | |
| CN115061286B (en) | Spectrum beam combining device and method | |
| CN114994933B (en) | Spectrum beam combining device and method | |
| CN115966995A (en) | Narrow linewidth external cavity laser device based on semi-confocal cavity | |
| CN113851921A (en) | Dual-wavelength laser output device and method, and semiconductor laser | |
| CN115327788B (en) | Spectrum beam combining device and method | |
| CN115079426B (en) | Spectrum beam combining device and method | |
| CN114994934B (en) | Spectrum beam combining device and method | |
| CN215989629U (en) | Narrow linewidth external cavity laser device based on semi-confocal cavity | |
| CN115128821B (en) | Spectrum beam combining device and method based on polarization separation external cavity feedback | |
| US11978996B2 (en) | Tunable external cavity laser with dual gain chips | |
| CN115128820A (en) | Chirp reflection type volume Bragg grating feedback spectrum beam combining device and method | |
| CN117578178A (en) | Single-bandwidth tuning inner cavity type Raman laser | |
| CN110994336A (en) | High-efficiency tunable terahertz laser based on angle tuning | |
| Jacobsson et al. | Tunable Single Mode ErYb: glass Laser Locked by a Bulk Glass Bragg Grating | |
| JP2006303416A (en) | Externally resonant semiconductor laser |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |