Powerful ultrabroadly tunable LW:F2+** laser

The LiF:F2+** laser has been shown' to provide high power (hundreds ofmJ), efficient (tens of%), room temperature stable laser operation tunable from 800 nm to nearly 1210 nm. However, no reasonable explanations were provided for such an ultrabroadband tuning capability using this active medium. This work describes the mechanism ofthe ullrabroadband lasing from LiF:F2+** und Alexandrite 1asa pumping. Alexandrite laser pump radiation corresponds to the regm of spectral overlapping in the absorption bands oftwo color cent in LW, namely F2+** and a new F2+**1ike center, conclusively discovered in this work. Using the Alexandrite laser's excitation, we can achieve simultaneous population inversion in both centers making F2+** and the F2**Iike centers, the primary color centers responsible for the ultrabroadband tunability. This work details the temperature-dependent spectroscopic measurements ofthese two color centers and the resulting laser charaderistics Absorption and fluorescence measuremits were performed from 300K to 13K. The room temperature (RT) absorption data shows that the F2+** center has maximum absorption at 614.5 nm and FWHM, Av 3819 cm'; the F2**like center has RT absorption at 813.4 nm and FWHM, Av 3592cnf. The fluorescence ofboth citers was measured using several excitation wavelengths from 532nm to 778 urn. F2+** demonstrated fluorescence emission from 7651080urn, corresponding to 10 % ofmaximum, and F2+**like from roughly 890-1400 mn, with fluorescence maxima at 905 nm and A.fl = 1098 nm, respectively.