High Power Laser Science and Engineering, Volume. 9, Issue 2, 02000e22(2021)
1178 J, 527 nm near diffraction limited laser based on a complete closed-loop adaptive optics controlled off-axis multi-pass amplification laser system
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Fig. 1. Schematic diagram of the 1178 J near diffraction limited 527 nm laser system using off-axis multi-pass amplification and complete closed-loop AO. BS, beamsplitter; CM, cavity mirror; DM, deformable mirror; L1–L10, focus lenses; M1–M7, IM1 and IM2, reflection mirrors; OSA, optical spectrum analyzer; PA, pinhole array; PEPC, plasma-electrode Pockels cell; SA, square aperture; TM, transport mirror.
Fig. 2. (a) Photo and (b) schematic diagram of the lab-manufactured DM; (c) hexagonally distributed 45 actuators in the DM; (d) interference fringe and (e) wavefront of the initial surface shape of the DM.
Fig. 4. (a), (c) Laser beam on the DM in configurations (a) C1 and (c) C2. (b), (d) Influence functions for the same actuator (i.e., the actuator in the blue dashed square in (a) and (c)) for configurations (b) C1 and (d) C2.
Fig. 5. Comparison between the representative eigenmodes of configurations C1 and C2. The first and third rows are for configuration C1 and the second and fourth rows are for configuration C2.
Fig. 6. Correction results of configurations C1 and C2 for the 3rd to 15th Zernike-mode aberrations: (a) PV and (b) RMS values of the residual errors.
Fig. 8. The target wavefront distortions to be corrected: (a) static wavefront distortion and (b) dynamic wavefront distortion.
Fig. 9. The wavefront distortions of the laser beam on the image plane before pinholes (a1) PA2, (b1) PA3, and (c1) PA4 and (d1) at the target; (a2)–(d2) are the corresponding distributions of the focal spots.
Fig. 10. (a), (b) Generated surface shapes of the DM to compensate the wavefront distortions for configurations C1 and C2, respectively; (c) residual wavefront error at the target after correction by using configuration C1; (d) distribution of the target focal spot after correction by using configuration C1.
Fig. 11. Residual errors of the wavefront distortions on the image plane before pinholes (a1) PA2, (b1) PA3, and (c1) PA4 and (d1) at the target after correction by using the configuration C2; (a2)–(d2) corresponding distributions of the focal spots.
Fig. 12. Experimental results: (a) static wavefront distortion of the entire beamline; (b) dynamic wavefront distortion of the main amplifier; (c) total wavefront distortion of the entire beamline composed of static and dynamic wavefront distortions; (d) residual error of the wavefront distortion at the target after correction; (e) distribution of the focal spot at the target before correction; (f) distribution of the focal spot at the target after correction.
Fig. 13. Measured wavefront distortion of the 527 nm laser at the target and the corresponding distribution of the focal spot for: (a1), (a2) the first shot; (b1), (b2) the second shot; (c1), (c2) the third shot.
Table 1. Parameters of the lenses.
View tableView in ArticleTable 1. Parameters of the lenses.
Lens L1 L2 L3 L4 L5 L6 L7 L8 L9 L10 Aperture (mm) $\phi$ $\phi$ $\phi$ $\phi$ 260×260 260×260 80×80 80×80 260×260 $\phi$ Thickness (mm) 3 3 8 8 30 30 10 10 30 2 Focal length (m) 0.15 0.15 0.69 1.38 6 6 2.1 1.75 2 0.05
Table 2. Parameters of the reflection mirrors.
View tableView in ArticleTable 2. Parameters of the reflection mirrors.
Mirror IM1 IM2 CM M1, M7 M2, M3, M4, M5, M6 TM BS Aperture (mm) 60×70 15×25 260×260 45×55 80×110 260×260 50×70 Thickness (mm) 10 5 40 10 20 40 5
Table 3. Parameters of the spatial filter pinholes.
View tableView in ArticleTable 3. Parameters of the spatial filter pinholes.
Pinhole PA1 PA2 PA3 PA4 Size (DL) 30 30 40 40 Size (mm) $\phi$ $\phi$ $\phi$ $\phi$
Table 4. Key parameters of the lab-manufactured DM.
View tableView in ArticleTable 4. Key parameters of the lab-manufactured DM.
Parameters Mirror Post Actuator Base Material BK7 BK7 Piezoelectric ceramic Steel Size 290 mm× $\phi$ 7 mm× 320 mm× 290 mm× 10 mm 7 mm× 320 mm× 10 mm 36 mm 80 mm
Table 5. Performance of the lab-manufactured DM.
View tableView in ArticleTable 5. Performance of the lab-manufactured DM.
Parameters Value Damage threshold of the mirror 9 J/cm2 @1053 nm, 1 ns Reflectivity of the mirror 99.95% @1053 nm, 1 ns Stroke of the actuator 12 μm Nonlinearity of the actuator 5% Hysteresis of the actuator 2% Initial surface shape of the DM 0.43 μm (PV), 0.06 μm (RMS) Open-loop bandwidth of the DM 50 Hz
Table 6. Residual errors and beam quality for three consecutive shots.
View tableView in ArticleTable 6. Residual errors and beam quality for three consecutive shots.
Laser shot 1st 2nd 3rd PV value of the residual error (μm) 0.40 0.43 0.44 Diameter of circle enclosing 80% energy (DL) 1.30 1.29 1.33
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Deen Wang, Xin Zhang, Wanjun Dai, Ying Yang, Xuewei Deng, Lin Chen, Xudong Xie, Dongxia Hu, Feng Jing, Zeping Yang, Qiang Yuan, Xiaofeng Wei, Qihua Zhu, Wanguo Zheng, Xiaomin Zhang, Lei Huang. 1178 J, 527 nm near diffraction limited laser based on a complete closed-loop adaptive optics controlled off-axis multi-pass amplification laser system[J]. High Power Laser Science and Engineering, 2021, 9(2): 02000e22
Paper Information
Category: Research Articles
Received: Jun. 13, 2020
Accepted: Jan. 19, 2021
Published Online: May. 24, 2021
The Author Email: Lei Huang (hl@tsinghua.edu.cn)
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