A Continuous-Wave Lyman-α Laser

We have demonstrated a nanowatt-level continuous-wave 121.6nm laser produced by resonantly-enhanced four-wave mixing in mercury vapor. This laser would be indispensable for cooling hydrogen or antihydrogen for more accurate spectroscopy. At the current power, the laser can cool atoms confined in a magnetic or dipole trap. Increasing the laser power to a microwatt could allow cooling a 4K hydrogen beam near a stand-still. We describe our efforts to enhance the nonlinear susceptibility in a tighter-focus regime where large power gains to the microwatt level are forseen.