Spatial intensity modulation in amplified laser beams,particularly hot spots,critically constrains attainable pulse peak power due to the damage threshold limitations of four-grating compressors.This study demonstrate...Spatial intensity modulation in amplified laser beams,particularly hot spots,critically constrains attainable pulse peak power due to the damage threshold limitations of four-grating compressors.This study demonstrates that the double-smoothing grating compressor(DSGC)configuration effectively suppresses modulation through directional beam smoothing.Our systematic investigation validated the double-smoothing effect through numerical simulations and experimental measurements,with comprehensive spatiotemporal analysis revealing excellent agreement between numerical and practical pulse characteristics.Crucially,the DSGC enables a 1.74 times energy output boost compared to conventional compressors.These findings establish the DSGC as a pivotal advancement for next-generation ultrahighpower laser systems,providing a viable pathway toward hundreds of PW output through optimized spatial energy redistribution.展开更多
A novel method,combining an asymmetric four-grating compressor(AFGC)with pulse post-compression,is numerically demonstrated to improve the spatial uniformity of laser beams and hence to suppress small-scale self-focus...A novel method,combining an asymmetric four-grating compressor(AFGC)with pulse post-compression,is numerically demonstrated to improve the spatial uniformity of laser beams and hence to suppress small-scale self-focusing(SSSF)during the beam propagation in nonlinear materials of high peak power lasers.The spatial uniformity of laser beams is an important factor in performing post-compression,due to the spatial intensity modulation,or hot spots will be aggravated during the nonlinear propagation and then seriously damage the subsequent optical components.Three-dimensional numerical simulations of post-compression are implemented based on a femtosecond laser with a standard compressor and an AFGC,respectively.The simulated results indicate that post-compression with the AFGC can efficiently suppress the SSSF and also shorten the laser pulses from 30 fs to sub-10 fs.This work can provide a promising route to overcome the challenge of SSSF and will be meaningful to promote the practical application of the post-compression technique in high peak power lasers.展开更多
An analytical expression for the focal intensity of a laser pulse was obtained for an asymmetric out-of-plane compressor with gratings of arbitrary surface shape. The focal intensity is most strongly affected by the l...An analytical expression for the focal intensity of a laser pulse was obtained for an asymmetric out-of-plane compressor with gratings of arbitrary surface shape. The focal intensity is most strongly affected by the linear angular chirp caused by the spatial shift of different frequencies on the second and third gratings. The chirp can be eliminated by simply rotating the fourth grating by an optimal angle, which significantly reduces the requirements for the grating quality. It is shown that the decrease in the focal intensity depends on the product of the grating surface root mean square and pulse spectrum bandwidth. With low-quality gratings, spectrum narrowing would not reduce focal intensity;contrariwise, it may even slightly increase it.展开更多
基金supported by the Shanghai Municipal Natural Science Foundation(Grant No.20ZR1464500)the National Natural Science Foundation of China(NSFC)(Grant Nos.61905257 and U1930115)+1 种基金the Shanghai Municipal Science and Technology Major Project(Grant No.2017SHZDZX02)the Ministry of Science and Higher Education of the Russian Federation(Project No.FFUF-2024-0038)。
文摘Spatial intensity modulation in amplified laser beams,particularly hot spots,critically constrains attainable pulse peak power due to the damage threshold limitations of four-grating compressors.This study demonstrates that the double-smoothing grating compressor(DSGC)configuration effectively suppresses modulation through directional beam smoothing.Our systematic investigation validated the double-smoothing effect through numerical simulations and experimental measurements,with comprehensive spatiotemporal analysis revealing excellent agreement between numerical and practical pulse characteristics.Crucially,the DSGC enables a 1.74 times energy output boost compared to conventional compressors.These findings establish the DSGC as a pivotal advancement for next-generation ultrahighpower laser systems,providing a viable pathway toward hundreds of PW output through optimized spatial energy redistribution.
基金supported by the National Key R&D Program of China(2022YFE0204800,2022YFA1604401,2019YFF01014401)Shanghai Sailing Program(21YF1453800)+5 种基金National Natural Science Foundation of China(11127901,61925507)International Partnership Program of Chinese Academy of Sciences(181231KYSB20200040)Shanghai Science and Technology Committee Program(22560780100,23560750200)Chinese Academy of Sciences President’s International Fellowship Initiative(2023VMB0008)Ministry of Science and Higher Education of the Russian Federation(075-15-2020-906,Center of Excellence‘Center of Photonics’)Youth Innovation Promotion Association of the Chinese Academy of Sciences。
文摘A novel method,combining an asymmetric four-grating compressor(AFGC)with pulse post-compression,is numerically demonstrated to improve the spatial uniformity of laser beams and hence to suppress small-scale self-focusing(SSSF)during the beam propagation in nonlinear materials of high peak power lasers.The spatial uniformity of laser beams is an important factor in performing post-compression,due to the spatial intensity modulation,or hot spots will be aggravated during the nonlinear propagation and then seriously damage the subsequent optical components.Three-dimensional numerical simulations of post-compression are implemented based on a femtosecond laser with a standard compressor and an AFGC,respectively.The simulated results indicate that post-compression with the AFGC can efficiently suppress the SSSF and also shorten the laser pulses from 30 fs to sub-10 fs.This work can provide a promising route to overcome the challenge of SSSF and will be meaningful to promote the practical application of the post-compression technique in high peak power lasers.
基金supported by the Ministry of Science and Higher Education of the Russian Federation(075-15-2022-316,Center of Excellence‘Center of Photonics’)
文摘An analytical expression for the focal intensity of a laser pulse was obtained for an asymmetric out-of-plane compressor with gratings of arbitrary surface shape. The focal intensity is most strongly affected by the linear angular chirp caused by the spatial shift of different frequencies on the second and third gratings. The chirp can be eliminated by simply rotating the fourth grating by an optimal angle, which significantly reduces the requirements for the grating quality. It is shown that the decrease in the focal intensity depends on the product of the grating surface root mean square and pulse spectrum bandwidth. With low-quality gratings, spectrum narrowing would not reduce focal intensity;contrariwise, it may even slightly increase it.
