130-W picosecond green laser based on a frequency-doubled hybrid cryogenic Yb:YAG amplifier

Abstract

130-W average-power picosecond green laser pulses at 514.5 nm are generated from a frequency-doubled hybrid cryogenic Yb:YAG laser. A second-harmonic conversion efficiency of 54% is achieved with a 15-mm-long noncritically phase-matched lithium triborate (LBO) crystal from a 240-W 8-ps 78-MHz pulse train at 1029 nm. The high-average-power hybrid laser system consists of a picosecond fiber chirped-pulse amplification seed source and a cryogenically-cooled double-pass Yb:YAG amplifier. The M(2) value of 2.7, measured at 77 W of second-harmonic power, demonstrates a good focusing quality. A thermal analysis shows that the longitudinal temperature gradient can be the main limiting factor in the second-harmonic efficiency. To our best knowledge, this is the highest-average-power green laser source generating picosecond pulses.

201 W picosecond green laser using a mode-locked fiber laser driven cryogenic Yb:YAG amplifier system

“…The system described here uses direct pulse amplification without pulse stretching or compression. A similar but somewhat more complex HAP green Yb:YAG cryogenic laser system has been described [2] that employed chirped-pulse-amplification (CPA) and produced 130 W of average power. HAP green sources have traditionally been produced using intracavity doubled acousto-optic Q-switched Nd:YAG and Nd:YLF lasers.…”

“…Cryogenic Yb based cryogenic lasers seem very promising in that regard. The favorable scaling of the thermal conductivity to higher values, as well as the significant decrease in the thermo-optic coefficient (dn=dT) and thermal expansion coefficients as temperature is lowered, has resulted in a number of recent demonstrations where the capability to be scaled to high average power with excellent beam-quality was achieved using CW, Q-switched, and mode-locked driven configurations [1][2][3][4][5][6]. The system used to produce the fundamental 1029 nm output is identical to that described in [1].…”

Multi-mJ, kHz intense picosecond deep ultraviolet source based on a frequency-quadrupled cryogenic Yb:YAG laser

“…Three single-mode Yb-doped fiber pre-amplifiers provided ~50 pJ at 82 MHz for the input energy of the cryogenic amplifier chain. To avoid damage due to the high peak power in the picosecond laser amplifier chain, we developed a narrowband CPA scheme based on a chirped volume Bragg grating (CVBG) pair with a chirp rate of ~100 ps/nm per bounce [5]. Out of 8 bounces off the CVBGs, we obtained positivelychirped pulses with a duration of ~560 ps and a bandwidth of 0.7 nm at 1029 nm.…”

The Application of Cryogenic Laser Physics to the Development of High Average Power Ultra-Short Pulse Lasers

“…We list, in order from left to right, the year, the crystal type, the pulse energy Ep, repetition rate ν r , average power Pav, the gain bandwith ∆λ C (from Table 6), laser operating wavelength λ L , the Gaussian transform-limited pulsewidth δt TL , the seed bandwidth ∆λ S , the seed pulsewidth δt TLS , the amplifier bandwidth ∆λ A , the amplifier expected pulsewidth δt TLA , the measured output pulsewidth δt MEAS , the peak power P P , and the corresponding reference [30,110,132,155,[158][159][160][161][162][163][164][165][166][167][168][169]. Other acronyms found in the Table are BC (before-recompression), AC (after-recompression), R (cryogenic regenerative amplifier), SHG (second-harmonic-generation), UC for (not re-compressed), and E for estimated.…”