  To generate laser with short wavelength is a bottle-neck problem in laser
technology. The extreme ultraviolet (EUV) lasers are usually produced with low
efficiency by nonlinear multi-photon process. Here we show the generation of
58.4 nm laser by a single-photon-excitation related stimulated anti-Stokes
Raman scattering (ASRS) with an efficiency higher than that of high harmonic
generation (HHG). Utilizing microwave excited helium in the metastable 1s2s
state irradiated by a resonant femto-second 2058 nm laser, we obtain pulsed
58.4 nm laser with a divergence of 1.9 mrad, suggesting its coherent character.
The pulse decay time of 426 ps shorter than the lifetime of spontaneous
emission also shows its stimulated property. Our results show an applicable
path towards up-conversion by single-photon process to generate intense laser
with wavelength shorter than 58.4 nm.
