Research Articles|147 Article(s)
Propagation characteristics of a high-power broadband laser beam passing through a nonlinear optical medium with defects
Xueqiong Chen, Xiaoyan Li, Ziyang Chen, Jixiong Pu, Guowen Zhang, and Jianqiang Zhu
The intensity distributions of a high-power broadband laser beam passing through a nonlinear optical medium with defects and then propagating in free space are investigated based on the general nonlinear Schr?dinger equation and the split-step Fourier numerical method. The influences of the bandwidth of the laser beam, the thickness of the medium, and the defects on the light intensity distribution are revealed. We find that the nonlinear optical effect can be suppressed and that the uniformity of the beam can be improved for a high-power broadband laser beam with appropriate wide bandwidth. It is also found that, under the same incident light intensity, a thicker medium will lead to a stronger self-focusing intensity, and that the influence of defects in the optical elements on the intensity is stronger for a narrowband beam than for a broadband beam.
High Power Laser Science and Engineering
  • Publication Date: Nov. 08, 2019
  • Vol.1 Issue, 3-4 3-43-4000132 (2013)
Energy measurement system of a large-aperture high power laser experiment platform
Yanwen Xia, Yue Liang, Sen Li, Junpu Zhao, Zhitao Peng, Hongguang Li, Hua Liu, Zhihong Sun, Kuixing Zheng, and Xiaofeng Wei
An energy measurement system in a Large-aperture high power laser experiment platform is introduced. The entire measurement system includes five calorimeters, which carry out the energy measurement of the fundamental frequency before the frequency conversion unit, remaining fundamental frequency, remain second-harmonics, third harmonics, as well as the energy balance measurement after the frequency conversion unit. Combinational indirect calibration and direct calibration are employed to calibrate the sampling coefficients of the calorimeters. The analysis of the data showed that, regarding the energy balance coefficients, combinational calibration approach gives a higher precision, and leads to an energy balance with 1%; and regarding the energy sampling coefficients for the various wavelengths after the frequency conversion, the results from direct and combinational calibration are consistent. The uncertainties for all energy sampling coefficients are within 3%, which guarantees the reliability of the energy measurement for the laser facility.
High Power Laser Science and Engineering
  • Publication Date: Nov. 08, 2019
  • Vol.1 Issue, 3-4 3-43-4000126 (2013)
kW-level, narrow-linewidth linearly polarized fiber laser with excellent beam quality through compact one-stage amplification scheme
Man Jiang, Pengfei Ma, Long Huang, Jiangming Xu, Pu Zhou, and Xijia Gu
In this manuscript, we demonstrate high-power, narrow-linewidth linearly polarized fiber laser with excellent beam quality through compact one-stage amplification scheme. By employing a single-mode–multimode–single-mode structure seed laser, a linearly polarized Yb-doped fiber laser with narrow linewidth and high output power is achieved. This laser, when used as a master oscillator, can be capable of suppressing the ASE in the process of power amplification. Thus, only one-stage amplification structure is used to scale up the laser power, and linearly polarized output with a polarization extinction ration of 14 dB, a narrow linewidth of 0.3 nm and an output power of 1018 W are achieved. Moreover, due to the good beam quality of seed laser and the well-designed amplifier stage, the beam quality of the output laser is near-diffraction-limited with $M_{x}^{2}\sim 1.18$ and $M_{y}^{2}\sim 1.24$ at the maximum power, and without mode instability occurring.
High Power Laser Science and Engineering
  • Publication Date: Dec. 12, 2017
  • Vol.5 Issue, 4 04000e30 (2017)
The special shaped laser spot for driving indirect-drive hohlraum with multi-beam incidence
Ping Li, Sai Jin, Runchang Zhao, Wei Wang, Fuquan Li, Mingzhong Li, Jingqin Su, and Xiaofeng Wei
High Power Laser Science and Engineering
  • Publication Date: Aug. 30, 2017
  • Vol.5 Issue, 3 03000e20 (2017)
Performance of an elliptical crystal spectrometer for SGII X-ray opacity experiments
Ruirong Wang, Honghai An, Zhiyong Xie, and Wei Wang
A new crystal spectrometer for application in X-ray opacity experiments is proposed. The conditions necessary to yield broad spectral coverage with a resolution ${>}$500, strong rejection of hard X-ray backgrounds and negligible source broadening for extended sources are formulated. In addition, the design, response modeling and reporting of an elliptical crystal spectrometer in conjunction with a linear detector are presented. The measured results demonstrate the performance of the new crystal spectrometer with a broad energy coverage range, high spectral resolution, and high luminosity (good collection efficiency). This spectrometer can be used in combination with point-projection backlighting techniques as utilized in X-ray opacity experiments. Specifically, the X-ray source, transmission and self-emission spectra of the sample can be measured simultaneously in a single shot, which can reduce the experimental uncertainties from shot-to-shot fluctuations. The new crystal spectrometer has been used in the X-ray opacity experiment to precisely measure the aluminum $K$-absorption edge shift in the energy range around 1.560 keV in strongly compressed matter. It is demonstrated that the spectrometer can be used to realize measurements of new and unpredictable physical interactions of interest, as well as basic and applied high-energy-density science.
High Power Laser Science and Engineering
  • Publication Date: Jan. 01, 1900
  • Vol.6 Issue, 1 010000e3 (2018)
Femtosecond laser-induced damage threshold in snow micro-structured targets
O. Shavit, Y. Ferber, J. Papeer, E. Schleifer, M. Botton, A. Zigler, and Z. Henis
Enhanced acceleration of protons to high energy by relatively modest high power ultra-short laser pulses, interacting with snow micro-structured targets was recently proposed. A notably increased proton energy was attributed to a combination of several mechanisms such as localized enhancement of the laser field intensity near the tip of $1~\unicode[STIX]{x03BC}\text{m}$ size whisker and increase in the hot electron concentration near the tip. Moreover, the use of mass-limited target prevents undesirable spread of absorbed laser energy out of the interaction zone. With increasing laser intensity a Coulomb explosion of the positively charged whisker will occur. All these mechanisms are functions of the local density profile and strongly depend on the laser pre-pulse structure. To clarify the effect of the pre-pulse on the state of the snow micro-structured target at the time of interaction with the main pulse, we measured the optical damage threshold (ODT) of the snow targets. ODT of $0.4~\text{J}/\text{cm}^{2}$ was measured by irradiating snow micro-structured targets with 50 fs duration pulses of Ti:Sapphire laser.
High Power Laser Science and Engineering
  • Publication Date: Mar. 19, 2018
  • Vol.6 Issue, 1 010000e7 (2018)