CN111964795A - Wavefront detection error measuring system and error measuring method thereof - Google Patents
Wavefront detection error measuring system and error measuring method thereof Download PDFInfo
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Abstract
The invention discloses a wavefront detection error measuring system and an error measuring method thereof. The invention adopts an optical fiber laser as a point light source, enters a wavefront measurement system of a system error to be measured as an ideal wavefront after being collimated and expanded by a collimating mirror, is received and measured by a wavefront detector, and is compared with the ideal wavefront to obtain the error of the wavefront measurement system; the wave front is fed back to the wave front waveform adjusting element to correct the laser wave front emitted by the high-power laser, so that the distortion caused by the error of a wave front measuring system is eliminated, and the real laser wave front of the high-power laser is obtained; the method and the device avoid the influence of corresponding system errors on laser wavefront measurement, calibrate the corresponding lens wavefront measurement system, and the optimized system has practicability and convenience, so that the measurement is more accurate.
Description
Technical Field
The invention relates to a laser wavefront detection technology, in particular to a wavefront detection error measuring system and an error measuring method thereof.
Background
Based on the proposal and application of chirped light pulse amplification technology, high-power ultrashort pulse laser technology is mature day by day. The application of the high-power ultrashort pulse laser promotes the experimental progress in multiple fields, and the results are quite high. The laser interacts with the target, accelerating electrons, protons, radiating X-ray and THz, etc., for further applications. As a new field, the development is rapid. With the further improvement of the laser power, the interaction between the laser and the target and the requirement of a plurality of technical parameters of the front-end laser are required to be achieved, so as to meet the purpose of subsequent experiments. The power, contrast, focal spot uniformity, wavefront, stability, etc. of a high-power ultrashort pulse laser all have parameter requirements. The wavefront is taken as an important index parameter of laser propagation, and has important influence on the subsequent laser far-field focusing state. The laser focusing state directly has influence on the interaction result of the rear-end experiment platform. Therefore, the method has important significance for wave front analysis of high-power ultrashort pulse laser. The high-power laser mainly comprises an oscillator, a stretcher, an amplifier, a compressor and the like, and can be used as a wavefront detector to detect different parts of wavefronts respectively, wherein the wavefront detector is mainly used for detecting the laser wavefronts at the position of a transmission section behind the compressor. At present, for high-power ultrashort pulse laser, especially for laser with power at the level of kilowatt level, the integral optical system framework is complex, and the size of an optical element is multiplied compared with that of the conventional laser. The large size of the optical element is easy to introduce various surface type distortions due to processing precision and deformation during processing, so that the wavefront quality of the laser is deteriorated after the laser is reflected or transmitted by the optical element. Meanwhile, in the laser amplification and transmission processes, wavefront distortion can be caused by thermal effect, nonlinear effect, air disturbance and the like, and finally laser focusing spots cannot reach the ideal size, the Sterler ratio is reduced, and the power density of laser energy focusing peak values is reduced. Therefore, the construction of an adaptive optical system is important for a high-power laser. The self-adaptive optical system measures and corrects the laser wave front of the high-power laser. High-power pulse lasers at home and abroad are provided with laser wavefront measurement and correction systems. The usual way of modifying parts is to use deformable mirrors. On the basis of a single deformable mirror, a double deformable mirror system is adopted by the mart, the korean GIST, and the shanghai optical machine to correct the wavefront.
The system measures the wavefront shape and intensity distribution of the light beam by analyzing the position and intensity of a light spot formed by imaging the light beam on a CCD camera with a micro-lens array, and the wavefront phase of the laser beam can be obtained by reconstructing through a Zernike mode method or an area method. The other is a shearing interferometry wavefront sensor, namely, a shearing interferometer is used for measuring the wavefront phase of a laser beam by an interference principle. The interference fringes contain difference information of the original wave front, and the original wave front can be reproduced through specific analysis and quantitative calculation combing (inverse Fourier transform).
In the two methods for measuring the wavefront distortion of the main optical path generated by the high-power laser, due to the problem of matching of the corresponding high-energy laser spot and the caliber of the detector, the wavefront measuring system of a single-lens or double-lens beam-shrinking system is often required to be used in cooperation. Therefore, when in measurement, because the lens in the wavefront measurement system is a transmission type element, the influence on the wavefront cannot be ignored, and the corresponding wavefront is measured to bring errors of the wavefront measurement system. Especially for high-power laser wavefront measurement, the proportion of systematic errors of the wavefront measurement brought by the wavefront measurement system is not small. When the wavefront correction is carried out, the wavefront distortion does not actually participate in the process of a main light path of laser propagation, so that error distortion introduced by a measuring system is counted, and the focusing state of the main light path laser deviates from an ideal state.
Disclosure of Invention
In order to avoid wavefront measurement deviation caused by errors of a wavefront measurement system, the invention provides a wavefront detection error measuring system which measures system errors of a corresponding wavefront measurement system and corrects the laser wave front of a main optical path, so that the wavefront of a real high-power laser is obtained.
It is an object of the present invention to provide a wavefront sensing error measurement system.
The main optical path comprises a high-power laser and a light energy attenuation sheet, wherein the high-power laser emits laser, and the energy is adjusted by the light energy attenuation sheet and enters the wavefront measuring system with the error to be measured as the main optical path.
The wavefront measuring system of the present invention includes: the device comprises a fiber laser, a collimating mirror, a measuring light path adjusting device, a translation table, a wavefront detector, a wavefront waveform adjusting element and a main light path adjusting device; the fiber laser, the collimating mirror and the measuring light path adjusting device are all arranged on the translation table; a wave front waveform adjusting element and a main light path adjusting device are arranged on a main light path between a high-power laser and a wave front measuring system; the fiber laser emits point light source laser as an ideal calibration light source; the point light source laser is collimated and amplified through a collimating mirror, so that the size of a light spot of the laser correspondingly enters a wavefront measuring system with a system error to be measured is matched with the caliber detected by a wavefront detector; the collimated and amplified laser is used for adjusting the direction of the whole laser through a measuring light path adjusting device, so that the direction of the laser is collimated and is coaxial with the wavefront measuring system, and the laser enters the wavefront measuring system as an ideal wavefront; laser emitted from the wavefront measuring system is received by a wavefront detector; the wavefront detector measures and obtains wavefront information, and compares the wavefront information with ideal wavefront to obtain the error of the wavefront measurement system; pushing the translation stage out of the optical path; feeding back the error of the wavefront measuring system to the wavefront waveform adjusting element; the high-power laser emits high-power ultrashort pulse laser, and the energy is adjusted through the light energy attenuation sheet; the laser after energy adjustment subtracts the error of the wavefront measurement system through the wavefront waveform adjusting element, and corrects the wavefront distortion caused by the error of the wavefront measurement system; then enters the wavefront measuring system through the main optical path adjusting device; the laser wave front emitted by the high-power laser device is emitted by the wave front measuring system and received by the wave front detector, and the wave front of the laser emitted by the high-power laser device, which eliminates wave front distortion caused by errors of the wave front measuring system, is obtained.
The collimating mirror adopts an off-axis parabolic mirror; the measuring light path adjusting device and the main light path adjusting device respectively adopt one or more reflectors, and the surface type controllability of the reflecting surface is good, so that the wavefront distortion brought by the whole measuring system is relatively small, and the influence on the measuring result is small. The off-axis parabolic mirror selected by the collimating mirror is a reflective beam expanding type, the surface shape of the collimating mirror is smaller than 1/50 lambda, lambda is the wavelength of laser, the introduced wave front distortion is little, and the measuring result is basically not influenced.
The wavefront waveform modifying element employs a deformable mirror. The deformable mirror includes a plurality of electrodes, each having an independent controller, that are individually controlled to vary the profile of the deformable mirror by applying a respective voltage to each electrode to vary the laser wavefront. And calculating the adjustment voltage required by each electrode in the deformable mirror according to the obtained wavefront distortion of the wavefront measurement system, and feeding back the adjustment voltage to the deformable mirror for adjustment and correction, so that the wavefront distortion brought by the wavefront measurement system is offset by the laser wavefront passing through the deformable mirror.
The beam-shrinking system in the wavefront measuring system is a convex lens selected for phase measurement, is a main part of an error source of the measuring system, is also a core part of the whole wavefront measuring system required to be measured, and light spots passing through the beam-shrinking system are matched with the aperture of the wavefront detector. The selection of the beam-shrinking system is mainly determined according to the parameters of the high-power ultrashort pulse laser emitted by the high-power laser, and after the large-size light spot of the high-power ultrashort pulse laser passes through the beam-shrinking system, the size of the laser at the imaging point is matched with that of the wavefront detector. The high-power ultrashort pulse has large corresponding optical spectrum width, so that the influence of chromatic aberration on the overall design scheme is reduced, the central wavelength of a convex lens of the wavefront measurement system is determined according to the wavelength of the high-power laser, the central wavelength of the convex lens is consistent with the central wavelength of the high-power laser, and the influence of chromatic aberration on the overall scheme is reduced on the basis of meeting the basic requirement of the scheme.
The high-power ultrashort pulse laser emitted by the high-power laser has the power of 2-10 PW and the pulse width of 20-60 fs.
The wavefront detector is a main measuring component for measuring the wavefront measurement system error, detects the wavefront of the incident light entering the instrument correspondingly, so that the system error of the whole system can be measured, and the system error of the corresponding measurement beam-shrinking system can be calibrated.
The wavefront sensor is located at an image point of the wavefront measurement system, and the deformable mirror is located on an object plane of the wavefront measurement system.
Another object of the present invention is to provide an error measurement method of a wavefront sensing error measurement system.
The error measuring method of the wavefront sensing error measuring system comprises the following steps:
1) placing the fiber laser, the collimating mirror and the measuring light path adjusting device on a translation table, and pushing the translation table into a light path;
2) the fiber laser emits point light source laser; the point light source laser is collimated and amplified through a collimating mirror, so that the size of a light spot of the laser correspondingly enters a wavefront measuring system with a system error to be measured is matched with the caliber detected by a wavefront detector;
3) the collimated and amplified laser is used for adjusting the direction of the whole laser through a measuring light path adjusting device, so that the direction of the laser is collimated and is coaxial with the wavefront measuring system, and the laser enters the wavefront measuring system as an ideal wavefront;
4) laser emitted from the wavefront measuring system is received by a wavefront detector;
5) the wavefront detector measures and obtains wavefront information, and compares the wavefront information with ideal wavefront to obtain the error of the wavefront measurement system;
6) pushing the translation stage out of the optical path;
7) feeding back the error of the wavefront measuring system to the wavefront waveform adjusting element;
8) the high-power laser emits high-power ultrashort pulse laser, and the energy is adjusted through the light energy attenuation sheet;
9) the laser after energy adjustment subtracts the error of the wavefront measurement system through the wavefront waveform adjusting element, and corrects the wavefront distortion caused by the error of the wavefront measurement system;
10) then enters the wavefront measuring system through the main optical path adjusting device; and finally, the laser wave front is emitted by the wave front measuring system and received by the wave front detector, and the laser wave front emitted by the high-power laser device, which eliminates wave front distortion caused by the error of the wave front measuring system, is obtained.
In step 2), the energy in the same solid angle is constant, so that the light intensity is inversely proportional to the square of the distance, and the fiber laser is positioned at the focus of the off-axis parabolic mirror, so that the light intensity of the laser is adjusted by adjusting the distance from the collimating mirror to the light source. According to the far field divergence angle of the fiber laser and the distance between the fiber laser and the collimating mirror, the size of the light spot passing through the collimating mirror is determined, and the size omega of the light spot meets the following requirements: ω is r × θ, ω is the spot size, r is the distance from the fiber laser to the collimator, and θ is the far field divergence angle of the fiber laser.
In the step 3), experimental results of the collimating lens verify that the coaxiality of the beam reducing system is different from the wavefront distortion of the whole beam reducing system, and when the coaxiality of the beam reducing system is good, the corresponding distortion is relatively small. The laser emitted from the collimating mirror is parallel plane waves, a circular diaphragm is arranged in front of the collimating mirror, the laser is blocked by the diaphragm, the light at the central part is reserved, a mark point is arranged at a distance position beyond 2m, the mark point is positioned at the center of a light spot, a wavefront measurement system is added at the moment, the height and the horizontal position of the wavefront measurement system are adjusted, so that the center of the light spot passing through a lens beam shrinking system is still overlapped with the mark point, meanwhile, the wavefront measurement system is rotated, the angle is finely adjusted, so that the light passing through the circular diaphragm and blocked is still circular instead of elliptical, and the wavefront measurement system is coaxial with the laser at the moment.
In step 5), the ideal wavefront is a perfect plane wave, and the phase of the whole wavefront is the same.
In step 7), calculating to obtain the adjustment voltage required by each electrode in the deformable mirror according to the obtained wavefront distortion of the wavefront measurement system, and feeding back the adjustment voltage to the deformable mirror for adjustment and correction, so that the wavefront distortion brought by the wavefront measurement system is offset by the laser wavefront passing through the deformable mirror.
In step 8), determining parameters of the wavefront measuring system according to optical parameters of the high-power ultrashort pulse laser emitted by the high-power laser and the size of the wavefront detector. The wavefront measuring system performs an imaging function. According to the experimental result, the wave-front detector is positioned at the image point of the wave-front measuring system, and the deformable mirror is positioned at the waveMeasuring the object plane of the system before; lens selection in a wavefront measurement system based on geometric optics lens imaging formula estimation
Wherein f is the focal length of the wavefront measuring system, v is the object distance, i.e. the distance from the deformable mirror to the wavefront measuring system, and u is the image distance, i.e. the distance from the wavefront detector to the wavefront measuring system. Estimating the ideal focus size of the light spot by utilizing diffraction limit according to the light spot size of the high-power ultrashort pulse laser
D is the diameter of the spot size.
The invention has the advantages that:
the invention adopts an optical fiber laser as a point light source, enters a wavefront measurement system of a system error to be measured as an ideal wavefront after being collimated and expanded by a collimating mirror, is received and measured by a wavefront detector, and is compared with the ideal wavefront to obtain the error of the wavefront measurement system; the wave front is fed back to the wave front waveform adjusting element to correct the laser wave front emitted by the high-power laser, so that the distortion caused by the error of a wave front measuring system is eliminated, and the real laser wave front of the high-power laser is obtained; the method and the device avoid the influence of corresponding system errors on laser wavefront measurement, calibrate the corresponding lens wavefront measurement system, and the optimized system has practicability and convenience, so that the measurement is more accurate.
Drawings
FIG. 1 is a schematic diagram of one embodiment of a wavefront sensing error measurement system of the present invention;
FIG. 2 is a schematic diagram of the beam reduction system coaxial alignment of an embodiment of the wavefront measurement error determination system of the present invention.
Detailed Description
The invention will be further elucidated by means of specific embodiments in the following with reference to the drawing.
As shown in fig. 1, the present embodiment performs error measurement for a beam reduction system, and the wavefront measurement error determination system of the present embodiment includes: the device comprises a fiber laser 7, a collimating mirror 8, a measuring light path adjusting device, a translation stage 11, a wavefront detector 6, a wavefront waveform adjusting element 3 and a main light path adjusting device; the fiber laser 7, the collimating mirror 8 and the measuring light path adjusting device are all arranged on the translation table 11, and the measuring light path adjusting device adopts a first reflecting mirror 9, a second reflecting mirror 109 and a second reflecting mirror 10; a wave front waveform adjusting element 3 and a main light path adjusting device are arranged on a main light path between the high-power laser 1 and the beam reducing system 5; the fiber laser 7 emits point light source laser as an ideal calibration light source; the point light source laser is collimated and amplified by the collimating mirror 8, so that the size of the reduced light spot of the laser which correspondingly enters the beam reducing system 5 with the system error to be measured is matched with the caliber detected by the wavefront detector 6; the collimated and amplified laser is used for adjusting the direction of the whole laser through a measuring light path adjusting device, so that the direction of the laser is collimated and is coaxial with the beam reducing system 5 and enters the beam reducing system 5 as an ideal wavefront; the laser emitted from the beam-reducing system 5 is received by a wavefront detector 6; the wavefront detector 6 measures to obtain wavefront information, and compares the wavefront information with an ideal wavefront to obtain an error of the beam-shrinking system 5; pushing the translation stage 11 out of the optical path; feeding back the error of the beam-reducing system 5 to the wavefront waveform adjusting element 3; the high-power laser 1 emits laser, and the energy is adjusted through the optical energy attenuation piece 2; the laser after energy adjustment subtracts the error of the beam reducing system 5 from the wave front waveform adjusting element 3, and corrects the wave front distortion caused by the error of the beam reducing system 5; then enters a beam shrinking system 5 through a main light path adjusting device, and the main light path adjusting device adopts a third reflector 4; and finally, the laser beam is emitted by the beam-reducing system 5, and the wavefront distortion of the laser wavefront caused by the error of the beam-reducing system 5 is corrected.
In this embodiment, the center wavelength of the high-power ultrashort pulse laser is 800nm, and the convex lens of the beam-shrinking system 5 selects an achromatic lens near the center wavelength of 800 nm.
The error measurement method of the wavefront sensing error measurement system of the present embodiment includes the following steps:
1) the fiber laser 7, the collimating mirror 8 and the measuring light path adjusting device are all placed on the translation table 11, and the translation table 11 is pushed into a light path.
2) The fiber laser 7 emits point light source laser, and the point light source laser is collimated and amplified by the collimating mirror 8, so that the size of the shrunk light spot of the laser correspondingly entering the beam shrinking system 5 with the system error to be measured is matched with the caliber detected by the wavefront detector 6:
the fibre laser 7 is here rated as an ideal wavefront source since the outgoing light has an ideal wavefront beam, similar to a point source. Since the light emitted by the fiber laser 7 is a point light source and is matched with the wave front detector 6 and the beam reducing system 5 for measuring the wave front by the high-power ultrashort pulse laser, the beam expansion and collimation of the wave front needs to be performed by the collimator. The collimator selects the off-axis parabolic mirror and reflects the beam, so that the surface shape can be controlled to be 1/50 lambda, lambda is the wavelength of the laser, introduced wavefront distortion is little, the measurement result is not affected basically, the off-axis parabolic mirror selects reflection at the angle close to 90 degrees, a point light source of the incident optical fiber laser 7 and the reflected beam expanding light are not in the same direction, and subsequent operation is facilitated. The fiber laser 7 is placed at the focus of the off-axis paraboloid, the distance from the collimating mirror 8 to the light source can be adjusted by selecting the focal length of the off-axis paraboloid, so that the average light intensity can be adjusted, and the size of the expanded beam light spot can be adjusted according to the far-field divergence angle of the fiber laser 7 and the size of the collimating mirror 8. For a fiber laser 7 with a far field divergence angle of 0.5rad, a focal length of 600mm off-axis parabolic mirror, a mirror size of 13 inches (330.2mm), the exit laser size is the same as the spot size of 300mm for the high power laser 1. The angle of the off-axis parabolic mirror can be adjusted to be approximately plane wave emergent. The two plane mirrors are positioned behind the corresponding off-axis parabolic mirrors and are also reflective plane mirrors, the surface type can be controlled to be 1/50 lambda, and the distortion effect on the laser wave front is negligible. The two reflectors adjust the direction of the emergent light to achieve the desired light direction, and are used for the subsequent coaxial fine adjustment of the beam-shrinking lens group. For convenient operation, the whole light source system is placed on the translation table 11 as a whole, the translation table 11 is pushed forward, light of high-power laser enters the subsequent measurement system when the translation table 11 is pushed out, and light of the optical fiber laser 7 enters the subsequent measurement system when the translation table 11 is pushed forward.
3) The collimated and amplified laser is adjusted in the direction of the whole laser through a measuring light path adjusting device, so that the direction of the laser is collimated and coaxial with the beam reducing system 5, and the laser enters the beam reducing system 5 as an ideal wavefront:
the beam-reducing system coaxiality is adjusted, referring to the lens coaxiality inside the beam-reducing system 5 and the coaxiality of the lens system and the ideal wavefront light source of fig. 2. Experimental results prove that the coaxiality of the beam reducing system 5 is different from the wavefront distortion of the whole beam reducing system 5, and when the coaxiality of the beam reducing system is good, the distortion brought by the coaxiality is relatively small.
The plane waves which are emitted in parallel can be obtained through the step 2), the diaphragm 12 is used for blocking light, the light of the central part is reserved, the mark point is arranged at the distance position which is beyond 2m, the mark point is positioned at the center of the light spot, the lens beam reducing system 5 is added at the moment, the left and right positions of the height of the lens are adjusted, the center of the light spot which passes through the lens beam reducing system 5 is still overlapped with the mark point, meanwhile, the angle rotation fine adjustment of the lens is adjusted, the light which passes through the circular diaphragm and is blocked is still circular instead of elliptical, and the lens beam reducing system 5 has the coaxiality with the light at the moment.
4) The laser light exiting the beam reduction system 5 is received by a wavefront sensor 6.
5) The wavefront detector 6 measures to obtain wavefront information, and compares the wavefront information with an ideal wavefront to obtain an error of the beam-shrinking system 5;
6) pushing the translation stage 11 out of the optical path;
7) feeding back the error of the beam-reducing system 5 to the wavefront waveform adjusting element 3;
8) the high-power laser 1 emits laser, and the energy is adjusted by the optical energy attenuation piece 2:
parameters of the lens beam-shrinking system 5 are determined according to optical parameters of the high-power ultrashort pulse laser and the size of the wavefront detector 6. After passing through the compressor, the high-power laser 1 has relatively large laser spot and relatively high optical power density, so that beam contraction and energy attenuation are required to be performed when the wavefront of the high-power ultra-short pulse laser is measured. Energy attenuation is achieved by using neutral density attenuation sheets or wedge reflection type attenuation,the attenuation location is typically located before the compressor. And the attenuator system 5 is located at the measuring position, after the compressor. The beam-reducing system 5 has two functions, on one hand, beam-reducing is carried out on the high-power ultrashort pulse laser to enable the size of the reduced beam to be matched with the size of a corresponding detector, on the other hand, the beam-reducing system 5 has an imaging function, and according to an experimental result, the accuracy of the measured wavefront of the detector is better when the detector is located near the position of an image point. The object plane is located at the deformable mirror of the wavefront sensor 6, which is placed at the imaging point of the wavefront measuring system. Lens selection can be estimated from geometric optical lens imaging formulas
Estimating the ideal focus size of the light spot by utilizing diffraction limit according to the light spot size of the high-power ultrashort pulse laser
And calculating an imaging position according to an imaging formula, and for a light spot size of 300mm, selecting an achromatic lens with a central waveband of 800nm of a focal length of 1m of a lens of the beam shrinking lens group, wherein the diffraction limit of the light spot with the central wavelength of 800nm of the high-power ultrashort pulse laser is 3 mu m, the distance of the deformable mirror is detected to be 15m, and a corresponding imaging point can be obtained to be positioned 7cm behind the beam shrinking lens.
9) The laser after energy adjustment subtracts the error of the beam reducing system 5 from the wave front waveform adjusting element 3, and corrects the wave front distortion caused by the error of the beam reducing system 5;
10) then enters a beam shrinking system 5 through a main light path adjusting device; and finally, the laser wavefront is emitted by a beam-shrinking system 5 and received by a wavefront detector 6, so that the laser wavefront with wavefront distortion caused by the error of a wavefront measurement system eliminated is obtained.
Finally, it is noted that the disclosed embodiments are intended to aid in further understanding of the invention, but those skilled in the art will appreciate that: various substitutions and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the invention should not be limited to the embodiments disclosed, but the scope of the invention is defined by the appended claims.
Claims (10)
1. The utility model provides a wavefront detection error survey system, measures corresponding wavefront measurement system's systematic error to revise before the laser wave to the main light path, the main light path includes high power laser instrument and light energy attenuation piece, and the high power laser instrument sends laser, adjusts the energy through light energy attenuation piece, gets into the wavefront measurement system to the volume of awaiting measuring error as the main light path, its characterized in that, wavefront detection error survey system includes: the device comprises a fiber laser, a collimating mirror, a measuring light path adjusting device, a translation table, a wavefront detector, a wavefront waveform adjusting element and a main light path adjusting device; the fiber laser, the collimating mirror and the measuring light path adjusting device are all arranged on the translation table; a wave front waveform adjusting element and a main light path adjusting device are arranged on a main light path between a high-power laser and a wave front measuring system; the fiber laser emits point light source laser as an ideal calibration light source; the point light source laser is collimated and amplified through a collimating mirror, so that the size of a light spot of the laser correspondingly enters a wavefront measuring system with a system error to be measured is matched with the caliber detected by a wavefront detector; the collimated and amplified laser is used for adjusting the direction of the whole laser through a measuring light path adjusting device, so that the direction of the laser is collimated and is coaxial with the wavefront measuring system, and the laser enters the wavefront measuring system as an ideal wavefront; laser emitted from the wavefront measuring system is received by a wavefront detector; the wavefront detector measures and obtains wavefront information, and compares the wavefront information with ideal wavefront to obtain the error of the wavefront measurement system; pushing the translation stage out of the optical path; feeding back the error of the wavefront measuring system to the wavefront waveform adjusting element; the high-power laser emits high-power ultrashort pulse laser, and the energy is adjusted through the light energy attenuation sheet; the laser after energy adjustment subtracts the error of the wavefront measurement system through the wavefront waveform adjusting element, and corrects the wavefront distortion caused by the error of the wavefront measurement system; then enters the wavefront measuring system through the main optical path adjusting device; the laser wave front emitted by the high-power laser device is emitted by the wave front measuring system and received by the wave front detector, and the wave front of the laser emitted by the high-power laser device, which eliminates wave front distortion caused by errors of the wave front measuring system, is obtained.
2. The wavefront sensing error measurement system of claim 1, wherein the collimating mirror is an off-axis parabolic mirror; the measuring light path adjusting device and the main light path adjusting device respectively adopt one or more reflectors.
3. The wavefront sensing error measurement system of claim 1, wherein the wavefront waveform modifying element employs a deformable mirror; the deformable mirror includes a plurality of electrodes, each having an independent controller, that are individually controlled to vary the mirror profile by applying a respective voltage to each electrode to vary the laser wavefront.
4. The wavefront sensing error measurement system of claim 1 wherein the wavefront sensor is located at an image point of the wavefront measurement system and the deformable mirror is located on an object plane of the wavefront measurement system.
5. The wavefront sensing error measurement system of claim 2, wherein the collimating mirror has a facet shape of less than 1/50 λ, λ being the wavelength of the laser light.
6. An error measurement method of the wavefront sensing error measurement system according to claim 1, wherein the error measurement method comprises the steps of:
1) placing the fiber laser, the collimating mirror and the measuring light path adjusting device on a translation table, and pushing the translation table into a light path;
2) the fiber laser emits point light source laser; the point light source laser is collimated and amplified through a collimating mirror, so that the size of a light spot of the laser correspondingly enters a wavefront measuring system with a system error to be measured is matched with the caliber detected by a wavefront detector;
3) the collimated and amplified laser is used for adjusting the direction of the whole laser through a measuring light path adjusting device, so that the direction of the laser is collimated and is coaxial with the wavefront measuring system, and the laser enters the wavefront measuring system as an ideal wavefront;
4) laser emitted from the wavefront measuring system is received by a wavefront detector;
5) the wavefront detector measures and obtains wavefront information, and compares the wavefront information with ideal wavefront to obtain the error of the wavefront measurement system;
6) pushing the translation stage out of the optical path;
7) feeding back the error of the wavefront measuring system to the wavefront waveform adjusting element;
8) the high-power laser emits high-power ultrashort pulse laser, and the energy is adjusted through the light energy attenuation sheet;
9) the laser after energy adjustment subtracts the error of the wavefront measurement system through the wavefront waveform adjusting element, and corrects the wavefront distortion caused by the error of the wavefront measurement system;
10) then enters the wavefront measuring system through the main optical path adjusting device; and finally, the laser wave front is emitted by the wave front measuring system and received by the wave front detector, and the laser wave front emitted by the high-power laser device, which eliminates wave front distortion caused by the error of the wave front measuring system, is obtained.
7. The error measurement method according to claim 6, wherein in step 2), the fiber laser is located at a focus of the off-axis parabolic mirror, so that the light intensity of the laser is adjusted by adjusting the distance from the collimator mirror to the light source; according to the far field divergence angle of the fiber laser and the distance between the fiber laser and the collimating mirror, the size of the light spot passing through the collimating mirror is determined, and the size omega of the light spot meets the following requirements: and omega is r multiplied by theta, r is the distance from the fiber laser to the collimating mirror, and theta is the far-field divergence angle of the fiber laser.
8. The error measurement method according to claim 6, wherein in step 3), the laser beam exiting from the collimator is a parallel plane wave, a circular diaphragm is placed in front of the collimator, the laser beam is blocked by the diaphragm, the light in the central portion is retained, a mark point is set at a distance of 2m away from the collimator so that the mark point is located at the center of the spot, a wavefront measurement system is added at this time, the height and the horizontal position of the wavefront measurement system are adjusted so that the center of the spot passing through the lens beam reduction system is still coincident with the mark point, and the wavefront measurement system is rotated to finely adjust the angle so that the light passing through the circular diaphragm and blocked is still circular instead of elliptical through the wavefront measurement system, and the wavefront measurement system is coaxial with the laser beam at this time.
9. The error measurement method according to claim 6, wherein in step 7), the adjustment voltage required by each electrode in the deformable mirror is calculated according to the obtained wavefront distortion of the wavefront measurement system, and the adjustment voltage is fed back to the deformable mirror for adjustment and correction, so that the wavefront distortion caused by the wavefront measurement system is cancelled by the laser wavefront passing through the deformable mirror.
10. The error determination method of claim 6, wherein in step 8), the wavefront sensor is located at an image point of the wavefront measurement system and the deformable mirror is located on an object plane of the wavefront measurement system; the focal length of the wavefront measurement system satisfies:
wherein f is the focal length of the wavefront measuring system, v is the object distance, i.e. the distance from the deformable mirror to the wavefront measuring system, and u is the image distance, i.e. the distance from the wavefront detector to the wavefront measuring system.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114361927A (en) * | 2022-01-06 | 2022-04-15 | 北京大学 | Method and device for correcting laser wavefront |
| CN114858291A (en) * | 2022-07-05 | 2022-08-05 | 中国工程物理研究院激光聚变研究中心 | Laser link segmented wavefront detection method and device based on point diffraction |
| CN114361927B (en) * | 2022-01-06 | 2024-05-24 | 北京大学 | Method and device for correcting laser wave front |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1648622A (en) * | 2005-02-06 | 2005-08-03 | 浙江大学 | Systematic error caliberation system and its method for near infrared pulse wavefront interferometer |
| WO2008021134A1 (en) * | 2006-08-16 | 2008-02-21 | Raytheon Company | Beam director and control system for a high energy laser within a conformal window |
| CN102608757A (en) * | 2012-03-09 | 2012-07-25 | 中国科学院上海光学精密机械研究所 | Device for increasing high-energy petawatt laser focusing power density and method |
| CN103760666A (en) * | 2014-01-16 | 2014-04-30 | 浙江师范大学 | Self-adaptive optical wavefront correction loop based on light wave reversible transmission |
| CN110018563A (en) * | 2019-03-29 | 2019-07-16 | 中国科学院长春光学精密机械与物理研究所 | The laser beam expanding Transmission system for expanding optical path compensation and method based on self-reflection light |
| CN110045496A (en) * | 2019-03-29 | 2019-07-23 | 中国科学院长春光学精密机械与物理研究所 | A kind of Sodium guide star atmospheric laser link compensation system |
-
2020
- 2020-09-15 CN CN202010966120.2A patent/CN111964795B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1648622A (en) * | 2005-02-06 | 2005-08-03 | 浙江大学 | Systematic error caliberation system and its method for near infrared pulse wavefront interferometer |
| WO2008021134A1 (en) * | 2006-08-16 | 2008-02-21 | Raytheon Company | Beam director and control system for a high energy laser within a conformal window |
| CN102608757A (en) * | 2012-03-09 | 2012-07-25 | 中国科学院上海光学精密机械研究所 | Device for increasing high-energy petawatt laser focusing power density and method |
| CN103760666A (en) * | 2014-01-16 | 2014-04-30 | 浙江师范大学 | Self-adaptive optical wavefront correction loop based on light wave reversible transmission |
| CN110018563A (en) * | 2019-03-29 | 2019-07-16 | 中国科学院长春光学精密机械与物理研究所 | The laser beam expanding Transmission system for expanding optical path compensation and method based on self-reflection light |
| CN110045496A (en) * | 2019-03-29 | 2019-07-23 | 中国科学院长春光学精密机械与物理研究所 | A kind of Sodium guide star atmospheric laser link compensation system |
Non-Patent Citations (3)
| Title |
|---|
| ROLAND J.SARLOT等: "Optical system for closed-loop testing of adaptive optic convex mirror", 《SPIE》 * |
| VLADIMIR TOPOROVSKY 等: "Applicability of small-size wavefront correctors to compensate for wavefront distortions in laser systems", 《SPIE》 * |
| 杨振刚 等: "内腔自适应光学系统校正激光器畸变", 《光学学报》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114361927A (en) * | 2022-01-06 | 2022-04-15 | 北京大学 | Method and device for correcting laser wavefront |
| CN114361927B (en) * | 2022-01-06 | 2024-05-24 | 北京大学 | Method and device for correcting laser wave front |
| CN114858291A (en) * | 2022-07-05 | 2022-08-05 | 中国工程物理研究院激光聚变研究中心 | Laser link segmented wavefront detection method and device based on point diffraction |
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