TUNABLE LASERS AT 1080NM FOR HELIUM OPTICAL-PUMPING

We describe the current status of tunable, cw, solid-state lasers in the infrared region of the spectrum which may be tuned to the helium resonance transition near 1083 nm. The principal use for these laser devices is the optical pumping of 3He and 4He atoms via the 2 3S1 metastable state. The tunable lasers we have examined include Nd3+-doped YAlO3, LaxNd 1-xMgAl11O19 (x ∼0.15), Nd:LiNbO 3, and Nd:silica glass fibers. Power outputs from these lasers range from a milliwatt to more than 1 W at the helium transition. Laser emission bandwidths range from less than 40 MHz (single-mode operation) to several GHz. Applications include magnetometry, dense nuclear targets, and polarized electron beams.