Ultraviolet pulse laser device, output light path autocollimation method and application thereof

Abstract

The application discloses an ultraviolet pulse laser device and an output light path autocollimation method and application, and comprises a control unit, a fundamental light source arranged along a light path direction, a wave band generating unit and a light beam pointing stability unit; the wave band generating unit is divided into a wave band I generating module, a wave band II generating module and a wave band III generating module and is used for generating wave band I, wave band II and wave band III respectively; the light beam pointing stability unit comprises an electrically-controlled lens I, an electrically-controlled lens II, a beam splitter I, a beam splitter II, a position detector I, a position detector II and a light shutter. The wavelength of the fundamental light is automatically adjusted, the corresponding crystal matching angle is adjusted and the corresponding delay line is inserted, so that pulse laser of the corresponding wavelength is generated, wide wave band ultraviolet pulse laser is generated through three-stage light path switching, and finally the output laser pointing stability is adjusted in real time through the autocollimation system.

Description

Technical Field

[0001] This application relates to an ultraviolet pulsed laser device and its output optical path self-collimation method and application, and particularly to a broadband self-tuning laser and its output optical path self-collimation method, belonging to the field of laser technology. Background Technology

[0002] Ultraviolet pulsed lasers have wide applications in precision machining, materials processing, nanobioengineering, and scientific research; some applications require pulsed lasers with continuously tuned wavelength output. Nonlinear frequency conversion technology is the most commonly used method to achieve ultraviolet pulsed laser output. However, for strong-field ultraviolet laser pulses, the main factors affecting the efficiency of nonlinear frequency conversion are group velocity mismatch in the time domain and walk-off effect in space. The most common solution is to use phase angle compensation of the crystal to solve the spatial walk-off effect and insert delay lines to compensate for the walk-off phenomenon in the time domain between two pulses, thereby solving the group velocity mismatch problem. However, for generating broadband tunable laser pulses, the crystal phase matching angle and the matching distance between delay lines are different for laser pulses of different wavelengths. Furthermore, the limited crystal tuning angle and frequency doubling efficiency limit the range of wavelengths that can be tuned within the same optical path. In particular, the pointing stability of output lasers of different wavelengths is poor, making it difficult to accurately illuminate the application terminal. Moreover, during the laser pointing correction process by the automatic control system, changes in laser pointing may damage other devices. Furthermore, if the wavelength tuning range is too large, the laser pointing deflection will be too great, exceeding the detection range of the position detector and causing the system correction to fail.

[0003] Therefore, providing an ultraviolet pulsed laser device capable of automatically and continuously outputting the required wavelength band, as well as an output optical path self-collimation device and self-collimation method during the laser wavelength tuning process, has become an urgent technical problem to be solved. Summary of the Invention

[0004] To address the problems of poor group velocity mismatch compensation and limited wavelength tuning range in current deep ultraviolet lasers with continuous wavelength tuning, as well as the tendency for the output optical path to deviate from the position detector of the collimation system during tuning, which can lead to collimation system failure, this application proposes an ultraviolet pulsed laser device capable of automatically and continuously outputting the desired wavelength band.

[0005] One aspect of this application provides an ultraviolet pulsed laser device, the ultraviolet pulsed laser device comprising:

[0006] The control unit and the fundamental frequency light source, band generation unit, and beam pointing stabilization unit arranged along the optical path direction;

[0007] The control unit is used to control the adjustment of the band generation unit and the beam pointing stabilization unit;

[0008] The band generation unit is divided into a band I generation module, a band II generation module, and a band III generation module, which are used to generate band I, band II, and band III, respectively.

[0009] The beam pointing stabilization unit includes: an electrically controlled lens I, an electrically controlled lens II, a beam splitter I, a beam splitter II, a position detector I, a position detector II, and an optical shutter;

[0010] The electrically controlled lens I, the beam splitter I, and the position detector I, arranged sequentially along the optical path, form the I-dimensional correction output optical path.

[0011] The second-dimensional correction output optical path is composed of an electrically controlled lens I, a beam splitter I, an electrically controlled lens II, a beam splitter II, and a position detector II arranged sequentially along the optical path direction.

[0012] The control unit controls the operation of the electrically controlled lens I, electrically controlled lens II, beam splitter I, beam splitter II, position detector I, position detector II, and optical shutter.

[0013] Optionally, in the ultraviolet pulsed laser device, the fundamental frequency light source has a tunable wavelength and adjustable power.

[0014] Optionally, the electrically controlled lens I is in front of the electrically controlled lens II.

[0015] Optionally, the band I generation module includes a beam splitter I, a second harmonic crystal I, a group velocity compensation crystal I, a third harmonic summation crystal, a beam splitter II, a group velocity compensation crystal II, a fourth harmonic summation crystal, and a beam combiner arranged sequentially along the optical path direction;

[0016] The band II generation module includes a beam splitter I, a second-harmonic crystal II, a fourth-harmonic crystal, and a beam combiner arranged sequentially along the optical path.

[0017] The Band III generation module includes a beam splitter I, a second harmonic crystal I, a group velocity compensation crystal I, a third harmonic summation crystal, a beam splitter II, and a beam combiner arranged sequentially along the optical path.

[0018] The output optical path of the fundamental frequency light source reaches the band generation unit via beam splitter I, and then reaches the beam pointing stabilization unit via beam combiner.

[0019] Optionally, the ultraviolet pulsed laser device has a large tuning band. Due to limitations in crystal tuning angle and frequency doubling efficiency, it is generated in three bands. The three bands are controlled by an electric beam splitter and beam combiner, and can be freely switched between each band.

[0020] Optionally, the group velocity compensation crystal is located between the frequency doubling crystal and the sum frequency crystal. The frequency doubling light generated by the frequency doubling crystal passes through the group velocity compensation crystal together with the fundamental frequency light, and then passes through the sum frequency crystal to obtain the sum frequency laser.

[0021] Optionally, the control unit is used to control the deflection angle of the second harmonic crystal I, the second harmonic crystal II, the third harmonic sum crystal, the fourth harmonic sum crystal, and the fourth harmonic crystal;

[0022] The control unit is used to control the incident angle of the group velocity compensation crystal I and the group velocity compensation crystal II.

[0023] The control unit is used to control the operation of the beam splitter I, beam splitter II, and beam combiner.

[0024] Optionally, the wavelength of band I generated by the band I generation module is 195-207 nm;

[0025] The center wavelength of band I is 200 nm.

[0026] Optionally, the wavelength generated by band I is between 195 and 207 nm. Different wavelengths of fundamental frequency light are converted to produce the band after passing through a second harmonic, a group velocity compensation crystal, a third harmonic sum-frequency conversion, a group velocity compensation crystal, and a fourth harmonic sum-frequency conversion. The center wavelength of this band is 200 nm.

[0027] Optionally, the wavelength of band II generated by the band II generation module is 207–247.5 nm;

[0028] The center wavelength of band II is 225 nm.

[0029] Optionally, the wavelength generated by band II is between 207 and 247.5 nm. Different wavelengths of fundamental frequency light are converted to produce this band after being subjected to second and fourth harmonics. The center wavelength of this band is 225 nm.

[0030] Optionally, the wavelength of band III generated by the band III generation module is 247.5–300 nm;

[0031] The center wavelength of band III is 266.7 nm.

[0032] Optionally, the wavelength generated by band III is between 247.5 and 300 nm. Different wavelengths of fundamental frequency light are converted to produce this band after passing through a second harmonic, a group velocity compensation crystal, a third harmonic, and a frequency converter. The center wavelength of this band is 266.7 nm.

[0033] Optionally, the electrically controlled lens I and / or electrically controlled lens II are reflectors;

[0034] The reflector is equipped with two orthogonal adjustment brackets, which correspond to the two orthogonal directions of the laser spot of the output optical path deviating from position detector I and / or position detector II, respectively.

[0035] Another aspect of this application provides an output optical path self-collimation method, which employs the aforementioned ultraviolet pulsed laser device;

[0036] The output optical path self-collimation method includes the following steps:

[0037] (1) The output optical path of the fundamental frequency light source reaches the position of the position detector I through the band generation unit, the motorized control lens I, and the beam splitter I;

[0038] If the laser spot I detected by the position detector I deviates from the center position of the position detector I, the motorized control lens I is adjusted until the laser spot I is at the center position of the position detector I.

[0039] (2) The output optical path of the fundamental frequency light source passes through the band generation unit, the motorized control lens I, the beam splitter I, the motorized control lens II, and the beam splitter II to reach the position of the position detector II;

[0040] If the laser spot II detected by the position detector II deviates from the center position of the position detector II, the electrically controlled lens II is adjusted until the laser spot II is at the center position of the position detector II.

[0041] Optionally, step (1) and / or step (2) further includes:

[0042] Images of the laser spot I and / or the laser spot II on the position detector I and / or the position detector II are acquired, then the spots are converted to grayscale, the contours of the spots are extracted, and the contours are fitted with circles.

[0043] Optionally, the laser spot I detected by the position detector I and / or the laser spot II detected by the position detector II may include a complete spot and / or a partial spot.

[0044] Optionally, step (1) and / or step (2) further includes: adjusting the light spot based on the circular profile obtained by circle fitting, wherein the method for adjusting the light spot includes:

[0045] S1. Extract the topmost position value Y1 and the bottommost position value Y2 of the fitted circular contour, calculate the middle position Y and compare it with the center position Y0 of the corresponding position detector I and / or position detector II.

[0046] S2. When Y is higher than Y0, adjust the Y-axis adjustment bracket of the corresponding motorized control lens I and / or motorized control lens II to lower. When Y is lower than Y0, adjust the Y-axis adjustment bracket of the corresponding motorized control lens I and / or motorized control lens II to raise until Y and Y0 coincide.

[0047] The overlap of Y and Y0 refers to an overlap within the error range;

[0048] S3: Extract the leftmost position value X1 and the rightmost position value X2 of the fitted circular contour, calculate the middle position X and compare it with the center position X0 of the corresponding position detector I and / or position detector II.

[0049] S4: When X deviates to the left of X0, adjust the X-axis adjustment bracket of the corresponding electric control lens I and / or electric control lens II to the right. When X deviates to the right of X0, adjust the X-axis adjustment bracket of the corresponding electric control lens I and / or electric control lens II to the left until X and X0 coincide.

[0050] The overlap of X and X0 refers to an overlap within the error range;

[0051] S5: When the wavelength tuning range is large, such as jumping from band 1 to band 3, or jumping from one end of the same band to the other end, it is necessary to first tune to the middle position of the band and then tune to the corresponding wavelength position. This can avoid the phenomenon of self-collimation failure caused by the output laser deviating from the position detector when the wavelength tuning range is too large.

[0052] Optionally, the output optical path self-collimation method further includes:

[0053] During the self-collimation process of the output optical path, the optical shutter is closed;

[0054] After the output optical path is self-collimated and calibrated, the shutter is opened to output light.

[0055] Another aspect of this application provides a method for generating a pulsed laser, the method employing the aforementioned ultraviolet pulsed laser device;

[0056] The method includes:

[0057] M1, The control system adjusts the set wavelength and power of the fundamental frequency light source output;

[0058] M2, The control system adjusts the band generation unit to a set position;

[0059] M3. Following the above-described output optical path self-collimation method, the output optical path is corrected, and the required pulsed laser is output after correction.

[0060] Wherein, M2 includes adjusting the phase matching angle of the second harmonic crystal I, the third harmonic sum crystal, the fourth harmonic sum crystal, the second harmonic crystal II, and the fourth harmonic crystal;

[0061] The M2 also includes adjusting the incident angles of group velocity compensation crystal I and group velocity compensation crystal II;

[0062] The M2 also includes a beam splitter I, a beam splitter II, and a beam combiner to reach the optical path of the band to be output.

[0063] Optionally, the method further includes a method for generating pulsed laser light through cross-band tuning, comprising the following steps:

[0064] M4-1. Correct the pointing stability of the output optical path of the generated pulsed laser according to the above-mentioned output optical path self-collimation method.

[0065] M5-1. Following the steps of M1 to M3, output the center wavelength of the band to which the pulse laser to be generated belongs, and perform output optical path pointing stability correction according to the above-mentioned output optical path self-collimation method.

[0066] M6-1. Following the steps of M1 to M3, output the wavelength of the pulsed laser to be generated, and perform output optical path pointing stability correction according to the above-mentioned output optical path self-collimation method.

[0067] Optionally, the method further includes a method for generating pulsed laser by co-band tuning, comprising the following steps:

[0068] M4-2. Correct the pointing stability of the output optical path of the generated pulsed laser according to the above-mentioned output optical path self-collimation method;

[0069] M5-2. Following the steps of M1 to M3, output the center wavelength of the generated pulsed laser band, and perform output optical path pointing stability correction according to the above-mentioned output optical path self-collimation method.

[0070] M6-2. Following the steps of M1 to M3, output the wavelength of the pulsed laser to be generated, and perform output optical path pointing stability correction according to the above-mentioned output optical path self-collimation method. The wavelength of the pulsed laser to be generated is in the same band as the pulsed laser generated in M4-2.

[0071] Optionally, the method for generating pulsed lasers by tuning within the same wavelength band is applicable to band III.

[0072] In another aspect of this application, an application is provided of the above-described ultraviolet pulsed laser device, the above-described output optical path self-collimation method, or the above-described pulsed laser generation method in a laser generating device, wherein the laser generating device includes a broadband self-tuned ultraviolet laser.

[0073] The beneficial effects that this application can produce include:

[0074] 1) This application generates pulsed laser of the corresponding wavelength by automatically adjusting the fundamental frequency wavelength, the corresponding crystal matching angle and inserting the corresponding delay line, and generates broadband ultraviolet pulsed laser by switching the optical path in three stages; finally, the output laser pointing stability is adjusted in real time by the self-collimation system; that is, the pulsed laser generator provided by this application can automatically, continuously and stably output pulsed laser of the required wavelength.

[0075] 2) This application can also correct the pointing stability of the output laser spot that exceeds the range of the position detector by curve fitting; it can also avoid damaging other devices during the self-collimation process of the output laser by adjusting the power of the fundamental frequency light and controlling the output valve. Attached Figure Description

[0076] Figure 1 This is a schematic diagram of the structure of a broadband self-tuning ultraviolet laser in an embodiment of this application;

[0077] Figure 2 This is a schematic diagram of the beam pointing stabilization unit in an embodiment of this application;

[0078] Figure 3 This is a schematic diagram of the spot processing steps in an embodiment of this application, wherein (a) is the original spot, (b) is the spot outline, and (c) is the outline circle fitting.

[0079] Figure 4 This is a position map of the light spot contour circle fitting in the position detector in the embodiments of this application;

[0080] Figure 5 The following is a schematic diagram of some light spot processing steps in the embodiments of this application, wherein (a) is the original light spot, (b) is the light spot outline, and (c) is the outline arc fitting;

[0081] Figure 6 This embodiment of the application shows the position map of the light spot contour circle fitted in the position detector, derived from the contour arc.

[0082] List of components and reference numerals:

[0083] 1. Fundamental frequency light source; 2. Beam splitter I; 3. Second harmonic crystal II; 4. Fourth harmonic crystal;

[0084] 5. Second harmonic crystal I; 6. Third harmonic sum crystal; 7. Beam splitter II; 8. Fourth harmonic sum crystal; 9. Beam combiner; 10. Group velocity compensation crystal I; 11. Group velocity compensation crystal II;

[0085] 12. Motorized control lens I; 13. Position detector I; 14. Beam splitter I; 15. Motorized control lens II; 16. Beam splitter II; 17. Position detector II; 18. Optical shutter; 19. Control system. Detailed Implementation

[0086] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0087] Unless otherwise stated, the materials and instruments used in the following examples are commercially available products or can be prepared by known methods.

[0088] Example 1

[0089] like Figure 1 , 2 As shown, a wideband self-tuning ultraviolet laser includes a control system 19, a fundamental frequency light source arranged along the optical path, a band generation unit, and a beam pointing stabilization unit; wherein, the control system 19 is used to control the adjustment of the fundamental frequency light source, the band generation unit, and the beam pointing stabilization unit.

[0090] The beam pointing stabilization unit includes: an electrically controlled lens I12, an electrically controlled lens II 15, a beam splitter I14, a beam splitter II 16, a position detector I13, a position detector II 17, and a shutter 18; wherein, the electrically controlled lens I12, the beam splitter I14, and the position detector I13 arranged sequentially along the optical path direction form the first-dimensional correction output optical path; the electrically controlled lens I12, the beam splitter I14, the electrically controlled lens II 15, the beam splitter II 16, and the position detector II 17 arranged sequentially along the optical path direction form the second-dimensional correction output optical path;

[0091] The control system 19 controls the operation of the electrically controlled lens I12, electrically controlled lens II 15, beam splitter I14, beam splitter II 16, position detector I13, position detector II 17, and shutter 18;

[0092] The band generation unit is divided into a band I generation module, a band II generation module, and a band III generation module, which are used to generate band I, band II, and band III, respectively.

[0093] The band I generation module includes a beam splitter I 2, a second harmonic crystal I 5, a group velocity compensation crystal I 10, a third harmonic summation crystal 6, a beam splitter II 7, a group velocity compensation crystal II 11, a fourth harmonic summation crystal 8, and a beam combiner 9 arranged sequentially along the optical path.

[0094] The band II generation module includes a beam splitter I 2, a second-harmonic crystal II 3, a fourth-harmonic crystal 4, and a beam combiner 9 arranged sequentially along the optical path.

[0095] The Band III generation module includes a beam splitter I 2, a second harmonic crystal I 5, a group velocity compensation crystal I 10, a third harmonic summation crystal 6, a beam splitter II 7, and a beam combiner 9 arranged sequentially along the optical path.

[0096] Example 2

[0097] Combination such as Figure 1-4 The schematic diagram shown illustrates the self-collimation method for the output optical path in detail. Using the broadband self-tuned ultraviolet laser obtained in Example 1, the specific steps are as follows:

[0098] S1: The control system 19 controls the closing of the light shutter 18. The output light path from the beam combiner 9 passes through the beam splitter I14 to reach the position of the position detector I13, collects the light spot 20 on the position detector I13, then converts the light spot to grayscale, extracts the contour 21 of the light spot image, and performs circle fitting 22 on the contour.

[0099] S2: Extract the uppermost position value Y1 and the lowermost position value Y2 of the fitted circular contour 22, calculate their midpoint Y and compare it with the center position Y0 of the position detector I13; when Y is higher than Y0, the control system 19 lowers the Y-axis adjustment frame of the electric control lens I12, and when Y is lower than Y0, the control system 19 raises the Y-axis adjustment frame of the electric control lens I12 until Y and Y0 coincide.

[0100] S3: Extract the leftmost position value X1 and the rightmost position value X2 of the fitted circle contour 22, calculate their midpoint X and compare it with the center position X0 of the position detector I13; when X is to the left of X0, the control system 19 adjusts the X-axis adjustment frame of the electric control lens I12 to the right, and when X is to the right of X0, the control system 19 adjusts the X-axis adjustment frame of the electric control lens I12 to the left until X and X0 coincide.

[0101] S4: The output optical path reaches the position of position detector II 17 through beam splitter II 16, acquires the light spot 20 on position detector II 17, then converts the light spot to grayscale, extracts the contour 21 of the light spot image, and performs circle fitting 22 on the contour.

[0102] S5: Extract the uppermost position value Y1 and the lowermost position value Y2 of the fitted circular contour 22, calculate their midpoint Y and compare it with the center position Y0 of the position detector II 17; when Y is higher than Y0, the control system 19 lowers the Y-axis adjustment frame of the motorized control lens II 15, and when Y is lower than Y0, the control system 19 raises the Y-axis adjustment frame of the motorized control lens II 15 until Y and Y0 coincide.

[0103] S6: Extract the leftmost position value X1 and the rightmost position value X2 of the fitted circle contour 22, calculate their midpoint X and compare it with the center position X0 of the position detector II 17; when X is to the left of X0, the control system 19 adjusts the X-axis adjustment frame of the motorized control lens II 15 to the right, and when X is to the right of X0, the control system 19 adjusts the X-axis adjustment frame of the motorized control lens II 15 to the left until X and X0 coincide.

[0104] S7: After the output optical path pointing is stabilized and corrected, the control system 19 controls the opening of the shutter 18 to output the pulsed laser of the required wavelength.

[0105] Example 3

[0106] Combination such as Figure 1-4 The schematic diagram shown illustrates the generation of a 196nm pulsed laser in band I using the broadband self-tuned ultraviolet laser obtained in Example 1; the specific steps are as follows:

[0107] S1: Control system 19 adjusts the fundamental frequency light source 1 to the set wavelength and power;

[0108] S2: Control system 19 adjusts the phase matching angle of second harmonic crystal I 5, third harmonic sum crystal 6, and fourth harmonic sum crystal 8 to the set position;

[0109] S3: Control system 19 adjusts the incident angle of group velocity compensation crystal I10 and the incident angle of group velocity compensation crystal II11 to the set position;

[0110] S4: The control system switches the optical path of beam splitter I 2, beam splitter II 7, and beam combiner 9 to band I;

[0111] S5: The output optical path direction is calibrated according to the method of Example 2, and the required 196nm wavelength pulsed laser is output after calibration.

[0112] Example 4

[0113] Combination such as Figure 1-4 The schematic diagram shown illustrates the generation of a 300nm pulsed laser in band III using the broadband self-tuned ultraviolet laser obtained in Example 1. The specific steps are as follows:

[0114] S1: Control system 19 adjusts the fundamental frequency light source 1 to the set wavelength and power;

[0115] S2: Control system 19 adjusts the phase matching angle of the second harmonic crystal I 5 and the phase matching angle of the third harmonic sum crystal 6 to the set position;

[0116] S3: Control system 19 adjusts the incident angle of group velocity compensation crystal I10 to the set position;

[0117] S4: Control system 19 switches the optical path of beam splitter I 2, beam splitter II 7, and beam combiner 9 to band III;

[0118] S5: The output optical path direction is calibrated according to the method in Example 2, and the required 300nm wavelength pulsed laser is output after calibration.

[0119] Example 5

[0120] Combination such as Figure 1-4 The schematic diagram shown illustrates the generation of a 230nm pulsed laser in band II using the broadband self-tuned ultraviolet laser obtained in Example 1. The specific steps are as follows:

[0121] S1: Control system 19 adjusts the fundamental frequency light source 1 to the set wavelength and power;

[0122] S2: Control system 19 adjusts the phase matching angle of the second harmonic crystal II 3 and the phase matching angle of the fourth harmonic crystal 4 to the set position;

[0123] S3: Control system 19 switches the optical path from beam splitter I 2 and beam combiner 9 to band II;

[0124] S5: The output optical path direction is calibrated according to the method of Example 2, and the required 230nm wavelength pulsed laser is output after calibration.

[0125] Example 6

[0126] Combination such as Figure 1-4 The schematic diagram shown illustrates the method for generating pulsed laser light during cross-band tuning using the broadband self-tuned ultraviolet laser obtained in Example 1. For instance, to generate a pulsed laser light with a wavelength of 300nm when the current output pulsed laser wavelength is 196nm, the specific steps are as follows:

[0127] S1: Correct the current output optical path pointing stability according to the method in Example 2;

[0128] S2: Generate a pulsed laser with a center wavelength of 266.7 nm for band III according to the method in Example 4;

[0129] S3: Correct the pointing stability of the output optical path with a center wavelength of 266.7nm according to the method in Example 2;

[0130] S4: Generate a pulsed laser with a wavelength of 300 nm according to the method of Example 4;

[0131] S5: Correct the pointing stability of the output optical path with a wavelength of 300nm according to the method in Example 2.

[0132] Example 7

[0133] Combination such as Figure 1-4 The schematic diagram shown illustrates a method for generating pulsed laser light using the broadband self-tuned ultraviolet laser obtained in Example 1, demonstrating how to achieve wide-range tuning within the same wavelength band. This method is primarily applied to band III. For example, if the current output pulsed laser wavelength is 300nm, the goal is to generate a pulsed laser with a wavelength of 248nm. The specific steps are as follows:

[0134] S1: Correct the current output optical path pointing stability according to the method in Example 2;

[0135] S2: Generate a pulsed laser with a center wavelength of 266.7 nm for band III according to the method in Example 4;

[0136] S3: Correct the pointing stability of the output optical path with a center wavelength of 266.7nm according to the method in Example 2;

[0137] S4: Generate a pulsed laser with a wavelength of 248 nm according to the method of Example 4;

[0138] S5: Correct the pointing stability of the output optical path with a wavelength of 248nm according to the method in Example 2.

[0139] Example 8

[0140] Combination such as Figure 1 , 2 The schematic diagrams shown in Figures 5 and 6 illustrate the self-collimation method of the output optical path when the output spot portion is on the position detector, using the broadband self-tuned ultraviolet laser obtained in Example 1. The specific steps are as follows:

[0141] S1: The control system 19 controls the closing of the light shutter 18. The output light path from the beam combiner 9 passes through the beam splitter I14 to reach the position of the position detector I13, collects the light spot 23 on the position detector I13, then converts the light spot to grayscale, extracts the contour 24 of the light spot image, performs arc fitting 25 on the contour, and derives the fitted circle 26 based on the fitted arc 25.

[0142] S2: Extract the topmost position value Y1 and the bottommost position value Y2 of the fitted circular contour 26, calculate their midpoint Y and compare it with the center position Y0 of the position detector I13; when Y is higher than Y0, the control system 19 lowers the Y-axis adjustment frame of the electric control lens I12, and when Y is lower than Y0, the control system 19 raises the Y-axis adjustment frame of the electric control lens I12 until Y and Y0 coincide.

[0143] S3: Extract the leftmost position value X1 and the rightmost position value X2 of the fitted circle contour 26, calculate their midpoint X and compare it with the center position X0 of the position detector I13; when X is to the left of X0, the control system 19 adjusts the X-axis adjustment frame of the electric control lens I12 to the right, and when X is to the right of X0, the control system 19 adjusts the X-axis adjustment frame of the electric control lens I12 to the left until X and X0 coincide.

[0144] S4: The output optical path reaches the position of the position detector 17 through the beam splitter II 16, collects the light spot 23 on the position detector II 17, then converts the light spot to grayscale, extracts the contour 24 of the light spot image, performs arc fitting on the contour 25, and derives the fitted circle 26 based on the fitted arc 25.

[0145] S5: Extract the topmost position value Y1 and the bottommost position value Y2 of the fitted circular contour 26, calculate their midpoint Y and compare it with the center position Y0 of the position detector II 17; when Y is higher than Y0, the control system 19 lowers the Y-axis adjustment frame of the motorized control lens II 15, and when Y is lower than Y0, the control system 19 raises the Y-axis adjustment frame of the motorized control lens II 15 until Y and Y0 coincide.

[0146] S6: Extract the leftmost position value X1 and the rightmost position value X2 of the fitted circle contour 26, calculate their midpoint X and compare it with the center position X0 of the position detector II 17; when X is to the left of X0, the control system 19 adjusts the X-axis adjustment frame of the motorized control lens II 15 to the right, and when X is to the right of X0, the control system 19 adjusts the X-axis adjustment frame of the motorized control lens II 15 to the left until X and X0 coincide.

[0147] S7: After the output optical path pointing is stabilized and corrected, the control system 19 controls the opening of the shutter 18 to output the pulsed laser of the required wavelength.

[0148] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An ultraviolet pulsed laser device, characterized in that, include: The control unit and the fundamental frequency light source, band generation unit, and beam pointing stabilization unit arranged along the optical path direction; The control unit is used to control the adjustment of the band generation unit and the beam pointing stabilization unit; The band generation unit is divided into a band I generation module, a band II generation module, and a band III generation module, which are used to generate band I, band II, and band III, respectively. The band I generation module includes a beam splitter I, a second-harmonic crystal I, a group velocity compensation crystal I, a third-harmonic sum crystal, a beam splitter II, a group velocity compensation crystal II, a fourth-harmonic sum crystal, and a beam combiner arranged sequentially along the optical path. The band II generation module includes a beam splitter I, a second-harmonic crystal II, a fourth-harmonic crystal, and a beam combiner arranged sequentially along the optical path. The Band III generation module includes a beam splitter I, a second harmonic crystal I, a group velocity compensation crystal I, a third harmonic summation crystal, a beam splitter II, and a beam combiner arranged sequentially along the optical path. The output optical path of the fundamental frequency light source reaches the band generation unit via beam splitter I, and reaches the beam pointing stabilization unit via beam combiner; The beam pointing stabilization unit includes: an electrically controlled lens I, an electrically controlled lens II, a beam splitter I, a beam splitter II, a position detector I, a position detector II, and an optical shutter; The electrically controlled lens I, the beam splitter I, and the position detector I, arranged sequentially along the optical path, form the I-dimensional correction output optical path. The second-dimensional correction output optical path is composed of an electrically controlled lens I, a beam splitter I, an electrically controlled lens II, a beam splitter II, and a position detector II arranged sequentially along the optical path direction. The control unit controls the operation of the electrically controlled lens I, electrically controlled lens II, beam splitter I, beam splitter II, position detector I, position detector II, and optical shutter.

2. The ultraviolet pulsed laser device according to claim 1, characterized in that, The control unit is used to control the deflection angles of the second harmonic crystal I, the second harmonic crystal II, the third harmonic sum crystal, the fourth harmonic sum crystal, and the fourth harmonic crystal; The control unit is used to control the incident angle of the group velocity compensation crystal I and the group velocity compensation crystal II. The control unit is used to control the operation of the beam splitter I, beam splitter II, and beam combiner.

3. The ultraviolet pulsed laser device according to claim 1, characterized in that, The wavelength of band I generated by the band I generation module is 195~207nm; The center wavelength of band I is 200 nm; The wavelength of band II generated by the band II generation module is 207~247.5nm; The center wavelength of band II is 225 nm; The wavelength of band III generated by the band III generation module is 247.5~300nm; The center wavelength of band III is 266.7 nm.

4. The ultraviolet pulsed laser device according to claim 1, characterized in that, The electrically controlled lens I and / or electrically controlled lens II are reflectors; The reflector is equipped with two orthogonal adjustment brackets, which correspond to the two orthogonal directions of the laser spot of the output optical path deviating from position detector I and / or position detector II, respectively.

5. A method for self-collimating the output optical path of a pulsed laser, characterized in that, The ultraviolet pulsed laser device according to any one of claims 1 to 4 is used; Includes the following steps: M1, the control unit adjusts the set wavelength and power of the base frequency light source output; M2, The control unit adjusts the band generation unit to a set position; M3, when tuning across or within a wide range of the same band, the control unit first controls the fundamental frequency light source and the band generation unit to output the center wavelength of the band to which the pulse laser to be generated belongs, and then performs pointing stability correction on the output optical path of the center wavelength. M4. After the center wavelength correction is completed, the target wavelength of the pulse laser to be generated is output, and the output optical path pointing stability is corrected again. The method for correcting the pointing stability of the output optical path includes: The output optical path of the fundamental frequency light source passes through the band generation unit, the electrically controlled lens I, and the beam splitter I to reach the position of the position detector I; an image of the laser spot I on the position detector I is acquired, then the spot is grayscaled, and then the outline of the spot is extracted and circle-fitted; if the fitted laser spot I deviates from the center position of the position detector I, the spot is adjusted according to the circle outline obtained by circle fitting until the laser spot I is at the center position of the position detector I. (2) The output optical path of the fundamental frequency light source passes through the band generation unit, the motorized control lens I, the beam splitter I, the motorized control lens II, and the beam splitter II to reach the position of the position detector II; the laser spot II on the position detector II is image acquired, then the spot is grayscaled, and then the outline of the spot is extracted and the outline is circle fitted; if the fitted laser spot II deviates from the center position of the position detector II, the spot is adjusted according to the circle outline obtained by circle fitting until the laser spot II is at the center position of the position detector II; The laser spot I collected by position detector I and the laser spot II collected by position detector II include complete spots and / or partial spots; The method for adjusting the light spot based on the circular contour obtained by circle fitting includes: Extract the topmost position value Y1 and the bottommost position value Y2 of the fitted circular contour, calculate the middle position Y and compare it with the center position Y0 of the corresponding position detector I or position detector II; when Y is higher than Y0, adjust the Y-axis adjustment frame of the corresponding motorized control lens to lower; when Y is lower than Y0, adjust the Y-axis adjustment frame of the corresponding motorized control lens to raise, until Y and Y0 coincide. Extract the leftmost position value X1 and the rightmost position value X2 of the fitted circular contour, calculate the middle position X and compare it with the center position X0 of the corresponding position detector I or position detector II; when X is to the left of X0, adjust the X-axis adjustment bracket of the corresponding motorized control lens to the right, and when X is to the right of X0, adjust the X-axis adjustment bracket of the corresponding motorized control lens to the left, until X and X0 coincide. During the self-collimation process of the output optical path, the optical shutter is closed; After the output optical path is self-collimated and calibrated, the shutter is opened to output light.

6. The application of the ultraviolet pulsed laser device according to any one of claims 1 to 3 or the pulsed laser generation and output optical path self-collimation method according to claim 5 in a laser generation device, characterized in that, The laser generating device includes a broadband self-tuning ultraviolet laser.

Images