Tunable cw laser emission has been observed at 30 K for the (a) variet
y of (F-2(+))(H) centres in NaCl:OH-. The output power is 160 mW at 14
97 nm for 2.4 W pump power at 1.064 mu m; the tuning range extends fro
m 1450 to 1600 nm. This performance is stable as a function of time. I
t may be significantly improved by use of an auxiliary beam (488 nm fr
om an Ar+ laser) but then the output is no longer stable, because this
auxiliary light slowly transforms (a) into (b) variety and the latter
becomes progressively responsible for the observed laser emission.