Progress of the injection laser system of SG-II

Abstract

A high power laser system was used to drive the ignition of inertial confinement fusion (ICF), of which the high energy, the uniform focal spot, the accurate laser waveform, and the synchronization between the laser beams are key parameters. To accomplish this, global laser characteristics control should be assured, which was the main purpose of the injection laser system. In this paper, the key technological progress involved in the improvement of the performance of the injection laser of SG-II is reported, including frequency domain control, time domain control, near-field spatial shaping, pre-amplifier technology, and the optical parametric chirped pulse amplification pump source.

Status and development of high-power laser facilities at the NLHPLP

“…Optical layout A schematic diagram of the overall layout of one beamline of the SG-II UP nanosecond system is shown in Figure 6. A laser pulse at a nanojoule level energy with a center frequency at 1053 nm is first generated in the front-end subsystem, where the pulse shaping and frequency fine tuning are also optimized [44] . Then it is successively preamplified to an approximate joule level in the preamplifier module where the spatial control is achieved.…”

“…It is known that the precise and stable synchronization between different beams is necessary for positive diagnostics, fast ignition research, and high performance implosion research. The SG-II UP facility utilizes the fiber stacker, high-speed electronics, and analog to digital conversion technology [44] to realize a simultaneous long and short pulse timing precision of (RMS) within a 2-h test. In addition, high-precision synchronous trigger signals [67] , optical and electrical signals for multi-channel physical tests, and diagnostics have been established.…”

“…(2) Flexible control techniques in the front-end, preamplifier system, and a high stability regenerative amplifier were developed. We independently researched and developed a polarization auto-feedback adjustment module based on fiber optic squeezing [44] . This technique improved the output stability of the nanosecond system.…”

Review of special issue on high power facility and technical development at the NLHPLP

“…Fan et al [5] report the key technological progress involved in the injection laser subsystem. Jiao et al [6] mainly summarize the design and performance of the final optics assembly in SG-II UP facility.…”

“…Fan et al. [5] report the key technological progress involved in the injection laser subsystem. Jiao et al.…”