Continuous-wave broadly tunable intracavity frequency-doubled Cr 4+: forsterite laser

Continuous-wave (CW) power performance of a room-temperature, broadly tunable intracavity frequency-doubled Cr⁴⁺: forsterite laser is described. Intracavity doubling was achieved by using a 2-cm-long periodically poled lithium niobate (PPLN) crystal. At the PPLN crystal temperature of 188°C, orange-red radiation could be obtained between 613 and 655 nm by using gratings with different poling periods. Experimentally measured temperature tuning data of the PPLN crystal was further found to be in very good agreement with theoretical predictions based on temperature-dependent Sellmeier data. With an incident pump power of 6.8 W at 1064 nm, the Cr⁴⁺: forsterite laser produced 245 mW of CW output power at 1260 nm and intracavity doubling yielded 45 mW of second harmonic output at 630 nm