A 60-mW solid-state deep ultraviolet (DUV) laser at 193 nm with narrow linewidth is obtained with two stages of sum frequency generation in LBO crystals. The pump lasers, at 258 and 1553 nm, are derived from a homemade Yb-hybrid laser employing fourth-harmonic generation and Er-doped fiber laser, respectively. The Yb-hybrid laser, finally, is power scaling by a 2 mm × 2 mm × 30 mm Yb:YAG bulk crystal. Accompanied by the generated 220-mW DUV laser at 221 nm, the 193-nm laser delivers an average power of 60 mW with a pulse duration of 4.6 ns, a repetition rate of 6 kHz, and a linewidth of ∼640 MHz. To the best of our knowledge, this is the highest power of 193- and 221-nm laser generated by an LBO crystal ever reported as well as the narrowest linewidth of 193-nm laser by it. Remarkably, the conversion efficiency reaches 27% for 221 to 193 nm and 3% for 258 to 193 nm, which are the highest efficiency values reported to date. We demonstrate the huge potential of LBO crystals for producing hundreds of milliwatt or even watt level 193-nm laser, which also paves a brand-new way to generate other DUV laser wavelengths.

提出了一种可同时实现高效率和大带宽的频率上转换技术，可将高能钕玻璃基频激光（波长1 054 nm）高效率地转换为紫蓝光波段的宽带2.5倍频激光（波长421.5 nm）.将窄带钕玻璃的倍频激光与中心波长为2 100 nm的宽带中红外激光以能量比4∶1进行非线性和频，并通过非共线构型实现位相匹配和群速度匹配，实验产生了能量为12.4 J、带宽为10.4 nm（相对带宽大于2%）的宽带2.5倍频激光.实验结果能够支撑紫蓝光波段百太瓦强激光的产生，为未来开发短波长的超短超强激光提供借鉴.