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The laser beamline in SULF facility
摘要： In this paper, we report the recent progress on the 1 PW/0.1 Hz laser beamline of Shanghai Superintense Ultrafast Laser Facility (SULF). The SULF-1 PW laser beamline is based on the double chirped pulse ampli?cation (CPA) scheme, which can generate laser pulses of 50.8 J at 0.1 Hz after the ?nal ampli?er; the shot-to-shot energy ?uctuation of the ampli?ed pulse is as low as 1.2% (std). After compression, the pulse duration of 29.6 fs is achieved, which can support a maximal peak power of 1 PW. The contrast ratio at ?80 ps before main pulse is measured to be 2.5 × 10?11. The focused peak intensity is improved by optimizing the angular dispersion in the grating compressor. The maximal focused peak intensity can reach 2.7 × 1019 W/cm2 even with an f /26.5 off-axis parabolic mirror. The horizontal and vertical angular pointing ?uctuations in 1 h are measured to be 1.89 and 2.45 μrad, respectively. The moderate repetition rate and the good stability are desirable characteristics for laser–matter interactions. The SULF-1 PW laser beamline is now in the phase of commissioning, and preliminary experiments of particle acceleration and secondary radiation under 300–400 TW/0.1 Hz laser condition have been implemented. The progress on the experiments and the daily stable operation of the laser demonstrate the availability of the SULF-1 PW beamline.
关键词： lasers,ultrafast lasers,titanium,laser ampli?ers
更新于2025-09-23 15:21:01
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Modeling of the 3D spatio-temporal thermal profile of joule-class -based laser amplifiers
摘要： Thermal pro?le modi?cation of an active material in a laser ampli?er via optical pumping results in a change in the material’s refractive index, and causes thermal expansion and stress, eventually leading to spatial phase aberrations, or even permanent material damage. For this purpose, knowledge of the 3D spatio-temporal thermal pro?le, which can currently only be retrieved via numerical simulations, is critical for joule-class laser ampli?ers to reveal potentially dangerous thermal features within the pumped active materials. In this investigation, a detailed, spatio-temporal numerical simulation was constructed and tested for accuracy against surface thermal measurements of various end-pumped Yb3+-doped laser-active materials. The measurements and simulations show an excellent agreement and the model was successfully applied to a joule-class Yb3+-based ampli?er currently operating in the POLARIS laser system at the Friedrich-Schiller-University and Helmholtz-Institute Jena in Germany.
关键词： diode-pumped solid-state lasers,ytterbium,laser ampli?ers,spatio-temporal thermal pro?le modeling,high intensity lasers
更新于2025-09-19 17:13:59
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High power all-fiberized and narrow-bandwidth MOPA system by tandem pumping strategy for thermally induced mode instability suppression
摘要： An all-?berized and narrow-bandwidth master oscillator power ampli?cation (MOPA) system with record output power of 4 kW level and slope ef?ciency of 78% is demonstrated. Tandem pumping strategy is tentatively introduced into the narrow-bandwidth MOPA system for thermally induced mode instability (TMI) suppression. The stimulated Brillouin scattering (SBS) effect is balanced by simply using one-stage phase modulation technique. With different phase modulation signals, SBS limited output powers of 336 W, 1.2 kW and 3.94 kW are respectively achieved with spectral bandwidths accounting for 90% power of ～0.025, 0.17 and ～0.89 nm. Compared with our previous 976 nm pumping system, TMI threshold is overall boosted to be >5 times in which tandem pumping increases the TMI threshold of >3 times. The beam quality (M 2 factor) of the output laser is well within 1.5 below the TMI threshold while it is ultimately saturated to be 1.86 with the in?uence of TMI at maximal output power. Except for SBS and TMI, stimulated Raman scattering (SRS) effect will be another challenge for further power scaling. In such a high power MOPA system, multi-detrimental effects (SBS, SRS and TMI) will coexist and may be mutual-coupled, which could provide a well platform for further comprehensively investigating and optimizing the high power, narrow-bandwidth ?ber ampli?ers.
关键词： optimization,design,laser ampli?ers,narrow linewidth,high power laser,laser systems,modeling,advanced laser technology and applications,?ber laser and applications
更新于2025-09-10 09:29:36