Production of intense, coherent, tunable narrow‐band lyman‐alpha radiation

Abstract

Nearly transform limited pulses of 1216 Å radiation have been generated by sum frequency generation in 0.1 to 10 torr of mercury vapor. The summed input beams, consisting of photons at 3127 Å and 5454 Å originate in 1 MHz band‐width ring‐dye laser oscillators. The beams are amplified in pulsed‐dye amplifiers pumped by the frequency doubled output of a Nd:YAG laser. The 3127 Å photons are tuned to be resonant with the two‐photon 61S to 71S mercury transition. The VUV radiation can be tuned by varying the frequency of the third non‐resonant photon. We have also observed difference frequency generation at 2193 Å and intense fluorescence from the 61P state at 1849 Å. We have studied the intensity and linewidth dependence of the 1849 Å fluorescence and 1216 Å sum frequency signals on input beam intensity, mercury density, and buffer gas pressure and composition.