CW laser operation of Nd:YLF

CW laser operation of Nd:YLF is reported for the first time and, in a comparison to Nd:YAG, exhibits a lower threshold and higher single-mode average power. The TEM 00 mode volume of Nd: YLF was observed to be a factor of four larger than Nd:YAG, resulting in twice the TEM 00 mode average power. This result is attributed to the substantially lower thermal lensing of YLF with respect to YAG. In comparative measurements the stimulated emission cross section of Nd:YLF was found to be 1.8 \times 10^{-19} cm ² for the π oscillation and 1.2 \times 10^{-19} cm ² for the σ oscillation, as compared to 2.4 \times 10^{-19} cm ² for Nd:YAG. The spectroscopic and lasing parameters of Nd:YLF indicate a potential for this material in high peak and average power Q -switched applications.