Contents
2018
Volume: 6 Issue 1
12 Article(s)

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Special Issue on Diode Pumped Solid State Lasers
Scaling diode-pumped, high energy picosecond lasers to kilowatt average powers
Brendan A. Reagan, Cory Baumgarten, Elzbieta Jankowska, Han Chi, Herman Bravo, Kristian Dehne, Michael Pedicone, Liang Yin, Hanchen Wang, Carmen S. Menoni, and Jorge J. Rocca
High Power Laser Science and Engineering
  • Publication Date: Mar. 19, 2018
  • Vol.6 Issue, 1 01000e11 (2018)
Laser system design for table-top X-ray light source
Anne-Laure Calendron, Joachim Meier, Michael Hemmer, Luis E. Zapata, Fabian Reichert, Huseyin Cankaya, Damian N. Schimpf, Yi Hua, Guoqing Chang, Aram Kalaydzhyan, Arya Fallahi, Nicholas H. Matlis, and Franz X. Kärtner
High Power Laser Science and Engineering
  • Publication Date: Mar. 21, 2018
  • Vol.6 Issue, 1 01000e12 (2018)
Special Issue on Focus on National Laboratory of High Power Laser and Physics, SIOM
Optimizing the cleanliness in multi-segment disk amplifiers based on vector flow schemes | On the Cover
Zhiyuan Ren, Jianqiang Zhu, Zhigang Liu, and Xiaowei Yang
The objective of maintaining the cleanliness of the multi-segment disk amplifier in Shenguang-II (SG-II) is to reduce laser-induced damage for optics. The flow field of clean gas, which is used for the transportation of contaminant particles, is a key factor affecting the cleanliness level in the multi-segment disk amplifier. We developed a gas–solid coupling and three-dimensional flow numerical simulation model. The three-dimensional and two-phase flow model is verified by the flow-field smog experiment and the particle concentration measurement experiment with the 130-disk amplifier in SG-II. By optimizing the boundary conditions with the same flow rate, the multi-inlet vector flow scheme can not only effectively reduce the purging time, but also prevent the reverse diffusion of contaminant particles in the multi-segment disk amplifier and the deposition of contaminant particles on the surface of the Nd:glass.
High Power Laser Science and Engineering
  • Publication Date: Jan. 24, 2018
  • Vol.6 Issue, 1 010000e1 (2018)
Target alignment in the Shen-Guang II Upgrade laser facility
Lei Ren, Ping Shao, Dongfeng Zhao, Yang Zhou, Zhijian Cai, Neng Hua, Zhaoyang Jiao, Lan Xia, Zhanfeng Qiao, Rong Wu, Lailin Ji, Dong Liu, Lingjie Ju, Wei Pan, Qiang Li, Qiang Ye, Mingying Sun, Jianqiang Zhu, and Zunqi Lin
The Shen-Guang II Upgrade (SG-II-U) laser facility consists of eight high-power nanosecond laser beams and one short-pulse picosecond petawatt laser. It is designed for the study of inertial confinement fusion (ICF), especially for conducting fast ignition (FI) research in China and other basic science experiments. To perform FI successfully with hohlraum targets containing a golden cone, the long-pulse beam and cylindrical hohlraum as well as the short-pulse beam and cone target alignment must satisfy tight specifications (30 and $20~\unicode[STIX]{x03BC}\text{m}$ rms for each case). To explore new ICF ignition targets with six laser entrance holes (LEHs), a rotation sensor was adapted to meet the requirements of a three-dimensional target and correct beam alignment. In this paper, the strategy for aligning the nanosecond beam based on target alignment sensor (TAS) is introduced and improved to meet requirements of the picosecond lasers and the new six LEHs hohlraum targets in the SG-II-U facility. The expected performance of the alignment system is presented, and the alignment error is also discussed.
High Power Laser Science and Engineering
  • Publication Date: Mar. 19, 2018
  • Vol.6 Issue, 1 01000e10 (2018)
Directly writing binary multi-sector phase plates on fused silica using femtosecond laser
Li Zhou, Youen Jiang, Peng Zhang, Wei Fan, and Xuechun Li
Light carrying orbital angular momentum (OAM) has a spatial distribution of intensity and phase, which attracts considerable interest regarding several potential applications in optical and quantum scenarios recently. Spiral phase plates are commonly used elements for generating and analyzing OAM states. In this study, we put forward a method of directly writing binary multi-sector phase plates using the femtosecond laser. These phase plates are engraved on fused silica, which could be applied in high-intensity regimes. Different binary multi-sector phase plates were generated with high quality, which were proved by the observation of their structures, accompanied by detecting the beam patterns with the Gaussian beams. The proposed method provides a crucial basis for the rapid manufacturing of phase plates using convenient equipment, which can generate the superposition OAM states and may lead to the capability of measuring the high-dimensional entanglement.
High Power Laser Science and Engineering
  • Publication Date: Mar. 05, 2018
  • Vol.6 Issue, 1 010000e6 (2018)
Systematic study of spatiotemporal influences on temporal contrast in the focal region in large-aperture broadband ultrashort petawatt lasers
Ping Zhu, Xinglong Xie, Jun Kang, Qingwei Yang, Haidong Zhu, Ailin Guo, Meizhi Sun, Qi Gao, Ziruo Cui, Xiao Liang, Shunhua Yang, Dongjun Zhang, and Jianqiang Zhu
Temporal contrast is one of the crucial physical determinants which guarantee the successful performance of laser–matter interaction experiments. We generally reviewed the influences on the temporal contrast in three categories of noises based on the requirement by the physical mechanisms. The spatiotemporal influences on temporal contrast at the focal region of the chromatic aberration and propagation time difference introduced by large-aperture broadband spatial filters, which were spatiotemporally coupled with compression and focusing, were calculated and discussed with a practical case in SG-II 5 PW ultrashort petawatt laser. The system-wide spatiotemporal coupling existing in large-aperture broadband ultrashort petawatt lasers was proved to be one of the possible causes of temporal contrast degradation in the focal region.
High Power Laser Science and Engineering
  • Publication Date: Mar. 19, 2018
  • Vol.6 Issue, 1 010000e8 (2018)
Research Articles
Faraday effect measurements of holmium oxide (Ho2O3) ceramics-based magneto-optical materials
David Vojna, Ryo Yasuhara, Hiroaki Furuse, Ondrej Slezak, Simon Hutchinson, Antonio Lucianetti, Tomas Mocek, and Miroslav Cech
Faraday effect measurements of holmium oxide (Ho2O3) ceramics-based magneto-optical materials, highly potential material candidates for high-energy laser Faraday isolators, are presented in this paper. Temperature dependence of the Verdet constant of nondoped Ho2O3 ceramics was measured for temperatures 15–305 K at $1.064~\unicode[STIX]{x03BC}\text{m}$ wavelength. The Verdet constant dispersion for wavelengths 0.5–$1~\unicode[STIX]{x03BC}\text{m}$ and $1.064~\unicode[STIX]{x03BC}\text{m}$ was measured for both nondoped Ho2O3 ceramics and Ho2O3 ceramics doped with terbium Tb3+ (0.2 at. %) and cerium Ce3+ (0.1 at. %) ions. The results suggest that the relatively low level of doping of Ho2O3 with these ions has no significant boosting impact on the Faraday effect. Therefore, other compositions of Ho2O3 ceramics-based magneto-optical materials, as well as various doping concentrations, should be further examined.
High Power Laser Science and Engineering
  • Publication Date: Jul. 02, 2018
  • Vol.6 Issue, 1 010000e2 (2018)
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: Jul. 02, 2018
  • Vol.6 Issue, 1 010000e3 (2018)
Pulsed LD side-pumped MgO: LN electro-optic cavity-dumped 1123 nm Nd: YAG laser with short pulse width and high peak power
Yang Bai, Bing Bai, Diao Li, Yanxiao Sun, Jianlin Li, Lei Hou, Mingxuan Hu, and Jintao Bai
We report a cavity-dumped 1123 nm laser with narrow pulse width and high peak power by an MgO: LN crystal electro-optic (EO) modulator. Based on the structural optimization design of a folded biconcave cavity using the 808 nm pulsed laser diode (LD) side-pumped ceramic Nd: YAG rod, output pulses with maximum pulse energy and peak power up to 39.6 mJ and 9.73 MW were obtained, corresponding to 100 Hz repetition rate and 4.07 ns pulse width. The instabilities of pulse width and pulse energy were $\pm$1.55% and $\pm$2.06%, respectively. At the highest repetition rate of 1 kHz, the pulse energy, pulse width, and peak power were 11.3 mJ, 5.05 ns, and 2.24 MW, respectively. The instabilities of pulse width and pulse energy were $\pm$2.65% and $\pm$3.47%, respectively.
High Power Laser Science and Engineering
  • Publication Date: Jul. 02, 2018
  • Vol.6 Issue, 1 010000e4 (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. 21, 2019
  • Vol.6 Issue, 1 010000e7 (2018)
Corrosion behaviors of the copper alloy electrodes in ArF excimer laser operation process
Xin Guo, Jinbin Ding, Yi Zhou, and Yu Wang
The corrosion behaviors of the ArF excimer laser copper alloy electrodes were studied. The morphology, composition and impurities were characterized by optical microscope, scanning electron microscopy, electron microprobe and glow discharge mass spectrometer methods. The anode produces the reef, the corrosion pits, the hole layer and the $1{-}10~\unicode[STIX]{x03BC}\text{m}$ level flake impurity. The cathode produces the particles, the sputtering pits, the element reduce layer and the $1~\unicode[STIX]{x03BC}\text{m}$ level particle impurity. Besides the Cu element, other elements in the alloy participate in the corrosion: Al element in the reef is over 1.5 times of the anode, Zn element in the particles is 1.3 times of the cathode, many trace elements congregate on the copper surface several and even hundreds of times. These elements are responsible to a great degree for the impurities and the rapid energy decline of the long-time idled laser.
High Power Laser Science and Engineering
  • Publication Date: Jul. 04, 2019
  • Vol.6 Issue, 1 010000e9 (2018)

About the Cover

Streamlines for the flow field of the multisegment disk amplifier. Figure (a) and (b) are flow field on the surface of optical elements, Figure (c) and (d) are flow field inside the multisegment disk amplifier. In either circumstance, there is no obvious turbulence in the flow field distribution, and the flow field of the clean gas is very smooth.