Speaker
Description
The next generation of laser-plasma accelerators (LPAs) require a novel laser architecture to support multi-kHz and multi-kW operation for scientific, medical, industrial and security applications. Combining pulsed fiber lasers spatially, temporally, and spectrally provides a viable path to high peak and high average power. Such lasers can also upgrade beam diagnostics, shaping, and stripping in radiofrequency accelerator facilities. To achieve ultrashort pulse durations as needed for applications, e.g. LPA drivers, we developed broadband spectral combining and comprehensive system dispersion compensation methods. In addition, to protect high power fiber amplifiers from damage during operation interruption, we developed a multilayer, high speed FPGA-based protection system.
We have built a three-spectral-channel, multi-stage fiber chirped pulse amplification (FCPA) laser system aimed at combining these spectral channels and achieving ~40fs compressed pulses after ~70dB gain. To reach transform-limited pulse durations, we have modeled the systemic dispersion at various orders from pulse propagation through a fiber-based stretcher, fiber amplifiers, and a grating compressor, and designed compensation schemes. We have also built an automated spectral phase mapping and optimization loop using programmable pulse shapers, and further achieved optimally compressed pulses from one spectral channel. We have demonstrated phase-locking of all three spectral channels using FPGA-based feedback controls, and are currently investigating coherent spectral combination and pulse compression.
Unwanted changes in seeding and pump conditions of high power laser amplifiers can result in damage to the system. We have designed and implemented an FPGA-based, multilayer, distributed protection system, via rapidly sensing errors in signal amplitude, duration, and timing, and stopping seed pulses and pump lasers, critical for multi-spectral-channel high power laser amplifier operation.
Work supported by the U.S. DOE, Office of Science, Office of High Energy Physics, under Contract No. DE-AC02-05CH11231, and the Moore Foundation, under Grant No. 10631.
| Working group | WG1 |
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