Continuous coherent radiation from wavelengths from 121 to 123 nm in the vacuum ultraviolet (VUV) was generated by four-wave sum-frequency mixing in mercury vapor. A yield of 20 nW at Lyman-alpha (121.57 nm) was achieved. We describe the experimental setup in detail and present a calculation of the nonlinear susceptibility, the phase-matching integral, and the VUV yield. The Lyman-alpha beam was used to perform 1S-2P spectroscopy in a cold beam of atomic hydrogen. Linewidths of only 120 MHz were observed, which is close to the natural linewidth.
|Publication status||Published - 2005|