Power-scalable ultrafast Ho:YAG slab amplifier at 2094 nm (Conference Presentation)
Power-scalable ultrafast Ho:YAG slab amplifier at 2094 nm (Conference Presentation)
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2094 nm 功率可扩展超快 Ho:YAG 板条放大器（会议演示）
DOI：
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发表时间：
2019
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影响因子：
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通讯作者：
Michael E. Reilly
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作者：
M. Esser;D. Morris;N. K. Stevenson;A. Lagatsky;Michael E. Reilly
我们提出了一个用于2微米超快激光脉冲的放大系统，用于潜在的材料加工应用。放大增益材料为10 mm×1.5 mm×55 mm的0.75at.%掺杂率的Ho：YAG板条晶体。泵浦光源为自行研制的连续波Tm：YLF板条激光器，最大输出功率为340W，中心波长为1908 nm Ho：YLF吸收峰。泵浦光束的全宽为0.2 mm×5.3 mm。实验的种子是锁模Tm：LuScO3激光器，它产生了以2094 nm为中心的200飞秒脉冲(~23.6 nm光谱带宽)。选择种子激光器的光谱峰，使Ho：YAG2090 nm和2097 nm发射峰光谱重叠。种子激光器的脉冲重复频率为115 MHz，经过光隔离器后测得的平均功率为~57 mW。在最初的实验中，使用球面双透镜对将种子聚焦到平板中，光束直径为0.2 mm。当泵浦功率为280W时，测得的单程增益为~10(最高可达0.54W)。在用于放大的增益体中，有效泵浦功率(不考虑透射泵浦光)估计为8.3W。在几种输出功率下，测量了输出信号的光谱带宽，结果表明，输出信号的光谱带宽收敛到~11.8 nm。基于这些结果和内部模拟，我们将实现一个前置放大器，并将2微米超短脉冲扩展到>；100W的平均功率(MHz PRF)。
We present an amplifier system for 2 µm ultrafast laser pulses for potential material processing applications. The amplifier gain material is a 0.75 at.% doped Ho:YAG slab crystal measuring 10 mm x 1.5 mm x 55 mm. The pump source is an in-house developed continuous wave Tm:YLF slab laser which produces a maximum output power of 340 W, centred at the 1908 nm Ho:YAG absorption peak. The pump beam full widths were 0.2 mm by 5.3 mm in the slab. The seed for the experiment was a mode-locked Tm:LuScO3 laser that produced 200 fs pulses (~23.6 nm spectral bandwidth) centred at 2094 nm. The spectral peak of the seed laser was chosen so as to spectrally overlap both the 2090 and 2097 nm emission peaks of Ho:YAG. The pulse repetition frequency of the seed laser was 115 MHz, and the average power as measured after an optical isolator was ~57 mW. In the initial experiment the seed was focused into the slab using a spherical doublet lens pair to a beam diameter of 0.2 mm. The measured single pass gain was ~10 (up to 0.54 W) when pumped with 280 W. The effective pump power (disregarding transmitted pump light) in the gain volume used for amplification was estimated to be 8.3 W. The spectral bandwidth of the output signal was measured at several output powers and shown to converge to ~11.8 nm. Based on these results and in-house simulations we will implement a pre-amplifier and scale 2 µm ultrashort pulses to >100 W average power at MHz PRFs.