CN115061286B - Spectrum beam combining device and method - Google Patents
Spectrum beam combining device and method Download PDFInfo
- Publication number
- CN115061286B CN115061286B CN202210845048.7A CN202210845048A CN115061286B CN 115061286 B CN115061286 B CN 115061286B CN 202210845048 A CN202210845048 A CN 202210845048A CN 115061286 B CN115061286 B CN 115061286B
- Authority
- CN
- China
- Prior art keywords
- laser
- grating
- transmission
- transmission grating
- output
- 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.)
- Active
Links
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; the reflection grating 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 incident to the transmission grating at different angles under the action of the conversion lens, and are diffracted by the transmission grating and then are incident to the reflection grating; the laser beam is output after being diffracted for many times by the transmission grating and the reflection grating. The spectrum beam combining device can realize effective beam combining without using an external cavity mirror, and meanwhile, through position transformation and optical path design, the dispersion capacity of a dispersion element can be improved by (2N+1) times, and further the spectrum beam combining spectrum width can be reduced by (2N+1) times, so that the spectrum beam combining light source application occasion can be expanded.
Description
Technical Field
The invention relates to the technical field of lasers, in particular to a dense spectrum beam combining device and method capable of multiplexing a transflective grating.
Background
Spectral beam combining technology is currently one of the most feasible techniques for achieving high-power, high beam quality beam combining lasers. From 1999 to date, this technology has been successfully applied to all solid state lasers, fiber lasers, and semiconductor lasers, greatly improving laser performance.
Basic principles and methods of spectral beam combining: based on an optical element with dispersion capability, such as a grating, a prism and the like, a plurality of unit laser beams with different lasing wavelengths are arranged according to a certain rule, the unit laser beams are output into a combined beam in a mode that near field and far field are overlapped through the dispersion effect of the dispersion element, the obtained combined beam has the sum of all unit laser beams with power, and the beam quality is similar to that of the unit laser beams, so that the combined beam output with high power and high beam quality is realized.
According to the principle, when the power and the beam quality of the laser are improved, the integral spectrum after the beam combination is also superposition of the spectrums of all the laser units, and as each laser unit has different center wavelengths (the necessary condition for realizing the beam combination of the spectrums), the integral spectrum of the combined laser is widened and is larger than the spectrum width of the laser unit. On the one hand, the method is difficult to apply to occasions with strict requirements on spectrum width; on the other hand, the beam combining performance of the rated bandwidth is improved only to a limited extent.
During spectral combining, how to increase the dispersive power of the dispersive element becomes critical. The current spectrum beam combination structure commonly adopts a single grating or single diffraction for realizing the chromatic dispersion effect, and the chromatic dispersion capability can be realized by adopting high-order diffraction or reducing grating constants according to the grating diffraction principle, so that the high-efficiency diffraction can be realized, the gratings adopted by the current spectrum beam combination are all first-order or negative-order diffraction gratings, and the high-dispersion can not be realized by adopting the high-order diffraction, so that the chromatic dispersion is mainly improved by reducing the grating constants and increasing the line number of unit sizes. Increasing the number of lines per millimeter can improve the dispersion capability to a certain extent, but at the same time, the diffraction angle is increased, the effective sectional area of the grating is reduced, and the problems of spectrum beam combination difficulty or cost and the like are aggravated. When the diffraction angle is larger than 65 °, it becomes very difficult to adjust the optical path, so that the diffraction angle of the grating currently used is usually smaller than 65 °, which also results in difficulty in improving the dispersive power of the grating by the number of lines.
The publication No. CN 107272214B and the publication Narrow-spectral-span spectral beam combining with a nonparallel double-grating structure (Chinese Optics Letters,2017,15 (9): 091403) propose a device for realizing the beam combination of semiconductor laser spectrum by utilizing double gratings, the dispersion capacity of a dispersion element can be improved by 2 times through the superposition of the double gratings, the laser spectrum broadening can be shortened to half of the original under the condition of unchanged laser cavity length, and the number of beam combination units can be doubled within the gain curve of the semiconductor laser and the wavelength range of high diffraction efficiency of the gratings, so that the power and the brightness are doubled; the publication No. CN107240856B, CN107240856B and the literature Narrow-wavelength-spread spectral combining laser with a reflector for a double pass with a single graining (Chinese Optics Letters,2018,16 (7): 071402) propose a spectrum beam combining device which utilizes a grating and a reflecting element to realize twice diffraction compression spectrum width, utilizes the reflecting element to reflect an incident light beam, realizes twice dispersion through the diffraction effect of the grating, improves the diffraction capacity of the grating by one time, compresses half of the spectrum width of an output laser spectrum, and equivalently achieves the same dispersion capacity of double-grating superposition.
From the above, the dispersive power can be further improved by superimposing more gratings. However, according to the above method, if the dispersion capability needs to be further improved, the grating needs to be further increased, which will certainly increase the number of devices and the cost, and the difficulty of tuning will also be further increased. However, the optical path becomes complicated, the installation and adjustment are not easy, and the cost is increased.
Disclosure of Invention
The invention aims to solve the problems and provides a spectrum beam combining device and a spectrum beam combining method for obviously improving the overall dispersion capacity by multiplexing a reflection grating and a transmission grating in a mode of superposing N transmission gratings and one reflection grating.
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 reflection grating 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 incident to the transmission grating at different angles under the action of the transformation lens, and are diffracted by the transmission grating and then are incident to the reflection grating; and the laser beam is output after being diffracted for many times by the transmission grating and the reflection grating.
Preferably, the laser unit array includes a first laser unit disposed at a middle position, and a second laser unit and a third laser unit symmetrically disposed at two sides of the first laser unit, respectively.
Preferably, by setting the output wavelength and the spatial position of the laser units, 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 a point on the transmission grating when diffracted for the second time on the transmission grating under the combined diffraction action of the conversion 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 a plurality of 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 or polarization direction adjustment on a laser beam output by the laser device, and the laser device is coated with an antireflection film on an end face of the output laser beam.
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 the spectrum beam combining method comprises the following steps:
s1, outputting laser beams by the laser unit array;
s2, the laser beam is incident to the transmission grating at different angles under the action of the transformation lens,
s3, the laser grating is diffracted by the transmission grating and then is incident to the reflection grating for diffraction;
s4, the laser beam is diffracted for a plurality of times by the transmission grating and the reflection grating and then is output to the external cavity mirror
The multiplexing light-transmitting grating dense spectrum beam combining device and method provided by the invention can realize effective beam combining without using an external cavity mirror, and meanwhile, through position conversion and optical path design, the dispersion capacity of a dispersion element can be improved (2N+1) times, so that the spectrum beam combining spectrum width can be reduced (2N+1) times, and the application occasion of a spectrum beam combining light source can be expanded.
Drawings
Fig. 1 is a schematic structural view of a spectrum combining device according to a first embodiment of the present invention.
Fig. 2 is a schematic structural view of a spectrum combining device according to a second embodiment of the present invention.
Fig. 3 is a schematic structural view of a spectrum combining device according to a third embodiment of the present invention.
FIG. 4 is a schematic diagram of a structure incorporating different period grating modulation to achieve different wavelength outputs
Fig. 5 is a schematic diagram of a structure for realizing different wavelength output by external grating feedback with different periods.
Fig. 6 is a schematic structural view of a spectrum combining device of a comparative example in the prior art.
Fig. 7 is a schematic diagram of the absorption spectrum of a gain fiber in a comparative example of the prior art.
Reference numerals
10. The laser unit 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 further described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only 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 reflection grating 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 incident to the transmission grating at different angles under the action of the transformation lens, and are diffracted by the transmission grating and then are incident to the reflection grating; and the laser beam is output after being diffracted for many times 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 the laser units in the laser unit array is only required to match the gain spectrum of the laser unit with the external cavity feedback wavelength and can resonate to the external cavity locking wavelength.
The multiplexing light-transmitting grating dense spectrum beam combining device and method provided by the invention can realize effective beam combining without using an external cavity mirror, and meanwhile, through position conversion and optical path design, the dispersion capacity of a dispersion element can be improved (2N+1) times, so that the spectrum beam combining spectrum width can be reduced (2N+1) times, and the application occasion of a spectrum beam combining light source can be expanded. In other embodiments, the spectral beam combining device of the present invention may also achieve efficient beam combining with the inclusion of an external cavity mirror by the cooperation of a piece of reflective grating with one or more pieces of transmissive grating.
As shown in fig. 1, a schematic structure of a spectrum combining apparatus according to a first embodiment of the present invention is shown, where the spectrum combining apparatus includes a laser unit array 10, a conversion lens 20, a reflection grating 40, a transmission grating 30, and an external cavity mirror 50, which corresponds to a cavity mirror of a laser resonator, and may specifically be a plane mirror, so that only light vertically incident on the external cavity mirror 50 and capable of returning to the laser unit along an original path can resonate, laser light not vertically incident on the external cavity mirror 50 cannot resonate but is lost, and finally, all laser beams vertically incident on the external cavity mirror 50 remain.
Specifically, 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, in a manner of one (i.e., one) transmission grating 30 and one (i.e., one) reflection grating 40. Specifically, the second laser unit 101, the first laser unit 100, and the third laser unit 102 arranged along the spectrum combining direction (x) output laser light along the same direction (z), wherein the output light of the first laser unit 100 at the center is the principal light 1001, and the second laser unit 101 and the third laser unit 102 are distributed on both sides of the first laser unit 100. After the laser beams output by the laser units are acted by the conversion lens 20, the laser beams are incident to the transmission grating 30 at different angles, the incidence angle of the main light 1001 at the transmission grating 30 is the littrow angle of the transmission grating 30, the main light 1001 is further incident to the reflection grating 40 after being diffracted by the transmission grating 30, a certain difference exists between the incidence angle of the main light 1001 at the reflection grating 40 and the littrow angle of the reflection grating 40, the angle difference is smaller than +/-5 degrees, the laser beams are further incident to the transmission grating 30 after being diffracted by the reflection grating 40, the laser beams output by the second laser unit 101, the first laser unit 100 and the third laser unit 102 are overlapped on the transmission grating 30, finally are diffracted out by the transmission grating 30 and are incident to the external cavity mirror 50, only the beams vertically incident to the external cavity mirror 50 are reflected, and the beams which can return to the original laser units can form resonance, and each laser unit resonance is enabled to be at different wavelength values through the same diffraction angle and different incidence angles of the transmission grating 30 and the reflection grating 40. In the whole resonant cavity light path, the diffraction capacity is overlapped for 3 times through the transmission grating 30 and the reflection grating 40 for 2 times, so that the integral dispersion capacity of the dispersion element is improved by 3 times, the incidence angle delta theta of the laser beam at the grating is unchanged, the laser beam is the same as that of the single grating, and the integral spectrum width can be compressed to 1/3 of that of the single grating according to the grating diffraction theory.
In a specific embodiment, the laser unit array 10 includes a laser unit, where 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 the laser device is coated with an antireflection film on an end face of the output laser beam; 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 high-efficiency diffraction polarization direction of the transmission grating 30 is matched with the polarization direction of the laser beam. In other embodiments, the number of the transmission gratings is two or more, for example, the number of the transmission gratings 30 is multiple, that is, the combination of multiple 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 the incident angle and the diffraction angle formed by the chief ray 1001 and the transmission gratings 30 are all rittrow 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 grating high-efficiency diffraction polarization direction 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.
Referring to fig. 2, a schematic structural diagram of a spectrum combining device according to a second embodiment of the present invention is shown, where the spectrum combining device includes a laser unit array 10, a conversion lens 20, a reflection grating 40, a transmission grating 30, and an external cavity mirror 50, and specifically, a combination of N transmission gratings 30 and one reflection grating 40 is adopted, and the other modes are basically the same as those of the first embodiment; the resonant cavity of the whole laser consists of the rear 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 coated with a high reflection film, and the rear cavity surface is coated with a high reflection film. The lasing wavelength of each laser unit is determined by the position of the optical components and the laser units within the cavity.
The second laser unit 101, the first laser unit 100, and the third laser unit 102 arranged along the spectrum combining direction (x) output laser light along the same direction (z), wherein the output light of the first laser unit 100 at the center position is the chief ray 1001, and the second laser unit 101 and the third laser unit 102 are distributed on both sides of the first laser unit 100. In order to facilitate the clear light path transmission process, in this figure, only the transmission process of the chief ray 1001 is illustrated. After the laser beams output by the laser units are acted by the conversion lens 20, the laser beams sequentially enter the first transmission grating 301, the second transmission grating 302 and the third transmission grating 303 and … … N 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 N transmission grating 30N further enters the reflection grating 40 and then is reversely transmitted after being diffracted by the reflection grating 40, the included angle between the incident light and the diffracted light of the reflection grating 40 is smaller than 10 degrees, the diffracted light sequentially enters the N 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 transmitted to the same position of the first transmission grating 301, are output along the diffraction direction of the first transmission grating 301 and enter the external cavity mirror 50, and only the light vertically enters the external cavity mirror 50 and can be effectively resonated after being returned to the laser units along the original path. All laser units resonate to different laser wavelengths due to the combined action of the external cavity feedback and the devices in the cavity, wherein the external cavity feedback refers to effective resonance laser formed by the external cavity mirror 50, and only the light beam which vertically enters the external cavity mirror 50 and can be fed back to the original laser unit can resonate the effective resonance light, so that light amplification is generated to form laser emission; the intracavity device is then broadly referred to as comprising all of the elements within the cavity which is 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 the various collimating and shaping optical elements. If the grating constants of all the transmission gratings 30 and the reflection gratings 40 are identical, and the dispersion capacities are identical, the laser beams output from the respective laser units undergo (2n+1) times of diffraction in the process of going to the external cavity mirror 50, the overall dispersion capacity is (2n+1) times of the dispersion capacity of a single grating, and compared with the single grating spectrum beam combining structure, the spectrum beam combining device structure of the present embodiment has an output spectrum width of 1/(2n+1) and a spectrum line width realizing effective compression.
The embodiment provides multiplexing N pieces of transmission gratings and 1 piece of reflection gratings, and can (2N+1) times improve the dispersion capacity of a dispersion element through position conversion and optical path design, so that (2N+1) times reduce the spectrum beam combination spectrum width, and the application occasion of the spectrum beam combination light source is facilitated to be expanded. In addition, the forward transmitted laser is folded to the direction of the laser unit for transmission through the introduction of the reflection grating, the light path is folded, the geometric dimension of the whole light source can be reduced to a certain extent, the light source miniaturization is facilitated, and 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, and in this embodiment, the spectral beam combining device includes a laser unit array 10, a conversion lens 20, a reflection grating 40, and a transmission grating 30, which are basically the same as those of 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 chip etching grating or external cavity feedback lock wavelength, and feedback adjustment through a later optical element is not needed. In order to achieve good beam quality, the output wavelength (λ 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 by the laser units intersect at a point, thereby achieving a combined output in which the near field and far field overlap. Specifically, as shown in fig. 4 and fig. 5, the structure diagrams for realizing different wavelength output by internal grating modulation with different periods and the structure diagrams for realizing different wavelength output by external grating feedback with different periods are respectively shown; as can be seen from the figure, in order to perform beam combination output of laser beams in such a manner that near field and far field overlap, an 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 is satisfiedThe laser beams output by each laser unit have the same diffraction angle and intersect at a point under the combined diffraction action of the conversion lens 20, the reflection grating 40 and the transmission grating 30, so that the effective beam combination can be still realized by the scheme of the embodiment without the external cavity mirror 50.
The invention further provides a spectrum beam combining method, which comprises the following steps:
s1, outputting laser beams by the laser unit array;
s2, the laser beam is incident to the transmission grating at different angles under the action of the transformation lens,
s3, the laser grating is diffracted by the transmission grating and then is incident to the reflection grating for diffraction;
s4, the laser beam is output after being diffracted for many times by the transmission grating and the reflection grating.
According to the multiplexing light-transmitting grating dense spectrum beam combining device and the multiplexing light-transmitting grating dense spectrum beam combining method, effective beam combining can be achieved under the condition that an external cavity mirror is not used, meanwhile, through position transformation and optical path design, the dispersion capacity of a dispersion element can be improved (2N+1) times, further the spectrum beam combining spectrum width can be reduced (2N+1) times, and the application occasion of a spectrum beam combining light source can be expanded.
Further description will be given below with reference to specific comparative examples and examples.
Comparative example
Fig. 6 is a schematic structural diagram of a spectrum beam combining device according to a comparative example in the prior art, specifically, a schematic diagram of spectrum beam combining based on a single-piece transmission grating, wherein 12 is a laser chip, a plurality of laser units are arranged in a spectrum beam combining direction (x) and emit along the same direction (z), the front cavity surface of each laser unit is plated with a high-reflection reducing film, after the effect of a conversion lens 20, all unit beams are converged on a transmission grating 30, and are diffracted by the transmission grating 30 and output onto an external cavity mirror 50, in order to achieve high diffraction efficiency, the incidence angle and the diffraction angle of an optical axis of the combined beam (generally the emitting direction of the laser unit in the middle position, the laser unit in the position 0 in the drawing) are equal to the littrow angle of the transmission grating 50, the laser units (-9 to-1, 1 to 9) on two sides have different incidence angles and the same diffraction angles on the grating, and the external cavity mirror 50 has a certain reflectivity, and is perpendicular to the littrow angle diffraction direction of the transmission grating 30. Only the light beam perpendicularly incident to the external cavity mirror 50 and reflected by the external cavity mirror 50 can be oscillated by forming an effective seed light, and the light beam which cannot be fed back to the outgoing laser unit is cut off or lost.
Taking 976nm semiconductor laser for optical fiber pumping as an example, fig. 7 is a schematic diagram of an absorption spectrum of an Yb gain optical fiber in the comparative example, and it can be seen from the figure that two curves respectively represent absorption light and emission light, there is an absorption peak at 976nm, the peak width at half maximum is about 4nm, and in order to achieve good pumping effect, the output wavelength of the 976nm laser is required to be within the absorption spectrum range, that is, the center wavelength is 976nm, the overall spectrum width is less than 4nm, and the smaller the overall spectrum width is, the better.
Taking a standard centimeter bar with 19 built-in laser units as a spectrum beam combining unit as an example, the width of a unit light emitting area is 100 mu m, the period interval is 500 mu m, an antireflection film is plated on the front cavity surface, the transmittance is more than 99.5%, TE linearly polarized light, the focal length of the adopted conversion lens 20 is 300mm, the grating constant of the transmission grating 30 is 625nm, the line number is 1600 lines/mm, the Littrow angle of the laser with the wavelength of 976nm is 51.33 degrees, the chromatic dispersion is 2.56mrad/nm, and the diffraction efficiency to S polarized light is over 95%.
In this comparative example, the conventional spectrum beam combining structure of a monolithic grating is used for spectrum beam combining, the incident angle and the diffraction angle at the transmission grating 30 are both 51.33 °, the center resonance wavelength of 19 laser units is as shown in table 1, the center 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 far greater than the 4nm requirement required for optical fiber pumping, according to the spectrum beam combining principle, and therefore the light source cannot be used for optical fiber laser pumping.
TABLE 1 resonant center wavelength of conventional spectral beam combining structure
Example 1
Based on the principle shown in fig. 4, the spectrum beam combining device structure of the present invention is specifically described by using a transmissive grating 30 and a reflective grating 40, the number of lines of the transmissive grating 30 and the reflective grating 40 is 1600 lines/mm, multiple diffractions occur according to the mode shown in fig. 2, the angle of incidence to the transmissive grating 30 for the first time and the diffraction angle are both 51.33 °, the incident angle of the laser beam after being diffracted by the transmissive grating 30 at the reflective grating 40 is 48 °, the diffraction angle is 54.99 °, the diffracted light of the reflective grating 40 returns to the transmissive grating 30, the incident angle at the transmissive grating 30 is 58.32 °, the corresponding diffraction angle is 45.33 °, and in order to achieve high diffraction efficiency, under the condition that the spatial position is sufficient, the incident angle and the diffraction angle of all gratings are as close to littrow angle as possible, and the included angle 304 of the two gratings is 3.33 °; and the center wavelength can be fine-tuned to a desired value by adjusting the angle of the outer endoscope 50. According to the grating diffraction equation, the center wavelength of each corresponding unit is shown in table 2, the center resonance wavelength is 976nm, the maximum resonance wavelength is 977.93nm, the shortest wavelength is 974.03nm, the whole bandwidth is 3.90nm, the spectrum width is effectively compressed 3 times, and the 4nm requirement of optical fiber pumping is met, so that the light source can be used for optical fiber laser pumping, and the application of the spectrum beam combining light source is expanded.
Table 2 example spectral beam combining structure resonant center wavelength
Example 2
On the basis of embodiment 1, if the number of the transmission gratings 30 is increased to 5, the overall dispersion capacity is improved by 11 times, the corresponding beam combining spectrum width can be compressed to 1.06nm, the unit number can be increased by 2.7 times within the bandwidth of 4nm, and the laser power can be further improved under the condition of meeting the spectrum requirement.
While embodiments of the present invention have been illustrated and described above, it will be appreciated that the above described embodiments are illustrative and should not be construed as limiting the invention. Variations, modifications, alternatives and variations of the above-described embodiments may be made by those of ordinary skill in the art within the scope of the present invention.
The above embodiments of the present invention do not limit the scope of the present invention. Any other corresponding changes and modifications made in accordance with the technical idea of the present invention shall be included in the scope of the claims of the present invention.
Claims (8)
1. The spectrum beam combining device is characterized by comprising a laser unit array, a conversion lens, a reflection grating and a transmission grating; the reflection grating is one; the number of the transmission gratings is N, and N is an integer greater than or equal to two;
the laser unit array comprises laser units, the laser units output laser beams, the laser beams are incident to the transmission grating at different angles under the action of the transformation lens, are diffracted by the transmission grating and then are incident to the reflection grating, adjacent transmission gratings are not parallel to each other, and the laser beams are output after being diffracted for many times by the transmission grating and the reflection grating; the first transmission grating which is incident after the laser beam output by the laser unit passes through the conversion lens is a first transmission grating;
through the setting of the output wavelength and the space position of the laser units, the diffraction angle of the second diffraction of the laser beam output by each laser unit on the first transmission grating is the same, and the laser beam output by each laser unit intersects with a point on the transmission grating when being diffracted for the second time on the first transmission grating under the combined diffraction action of the conversion lens, the reflection grating and the transmission grating.
2. The optical spectrum combining device as claimed in claim 1, wherein the laser unit array comprises a first laser unit disposed at a middle position, and a second laser unit and a third laser unit symmetrically disposed at both sides of the first laser unit, respectively.
3. The optical spectrum combining device as claimed in claim 1, further comprising an external cavity mirror, wherein the laser beam is output to the external cavity mirror after being diffracted a plurality of times by the transmission grating and the reflection grating.
4. The spectral beam combining apparatus of claim 1, wherein the reflection grating is a first order diffraction grating, the reflection grating has a first order diffraction efficiency greater than 90%, and the diffraction polarization direction of the reflection grating matches the polarization direction of the laser beam.
5. The spectral beam combining apparatus 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.
6. The optical spectrum beam combining apparatus of claim 1, wherein the laser unit array comprises a laser unit, the laser unit comprises 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 the laser device is coated with an antireflection film on an end face of the output laser beam.
7. The optical spectrum combining apparatus of claim 6 wherein the laser device is a semiconductor laser, a fiber laser, or an all-solid-state laser.
8. A method of spectral beam combination, characterized in that it is achieved by a spectral beam combination device according to any one of claims 1 to 7, comprising the steps of:
s1, outputting laser beams by the laser unit array;
s2, the laser beam is incident to the transmission grating at different angles under the action of the transformation lens,
s3, the laser grating is diffracted by the transmission grating and then is incident to the reflection grating for diffraction;
s4, the laser beam is output after being diffracted for many times by 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 CN115061286A (en) | 2022-09-16 |
| CN115061286B true 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 |
|---|---|
| CN115061286A (en) | 2022-09-16 |
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 | |
| US7006550B2 (en) | Traveling-wave lasers with a linear cavity | |
| US20060176914A1 (en) | Laser with narrow bandwidth antireflection filter for frequency selection | |
| US5949804A (en) | Semiconductor light emission device | |
| Lin et al. | Generation of high brightness diode laser by using spectral and polarization beam combination | |
| 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 | |
| Jacobsson et al. | Tunable Yb: KYW laser using volume Bragg grating in s-polarization | |
| CN115327788B (en) | Spectrum beam combining device and method | |
| Nair et al. | Double wavelength operation of a grazing incidence tunable dye laser | |
| CN115079426B (en) | Spectrum beam combining device and method | |
| US11978996B2 (en) | Tunable external cavity laser with dual gain chips | |
| CN114994934B (en) | Spectrum beam combining device and method | |
| CN215989629U (en) | Narrow linewidth external cavity laser device based on semi-confocal cavity | |
| CN117578178A (en) | Single-bandwidth tuning inner cavity type Raman laser | |
| US9331455B1 (en) | Frequency locked diode laser devices exhibiting low power penalty | |
| Hemmer et al. | Spectral narrowing in a dual volume Bragg grating Ti: Sapphire oscillator | |
| JPH05211369A (en) | Laser diode pumping solid laser | |
| CN114465088A (en) | Wavelength locking system | |
| Jacobsson et al. | Tunable Single Mode ErYb: glass Laser Locked by a Bulk Glass Bragg Grating | |
| Moser et al. | A novel tunable diode laser using volume holographic gratings | |
| JPH0462880A (en) | Laser diode pumping solid-state 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 |