Diode-Pumped Yb3+:YLF and Yb3+:CaF2 Laser Performance

We report an extensive comparison of the laser performances of diode-pumped Yb3+:YLF (30% at.) and Yb3+:CaF2 (5% at.) crystals, lasing at room-temperature and operating in two different operation modes, i.e. Continuous Wave (CW) and quasi-CW. An in-depth investigation of the crystals behavior by changing the pump power, clearly shows that the crystal absorption depends on the lasing conditions. Therefore, we report an unambiguous evaluation of the slope efficiency calculated taken into account the real measured crystal absorption under laser action. Finally, we present a study of problems related to thermally induced losses which are expected influencing the laser performance.