Recent progress in cryogenic Yb:YLF laser technology

Abstract

Yb:YLF crystal with near-unity quantum efficiency attracts the attention of researchers in high-power laser development and laser-cooling communities. Here, we will review our recent efforts in energy and average/peak power scaling of room temperature and cryogenic Yb:YLF lasers and amplifiers. At first, we will present temperature dependence of important laser related parameters in Yb:YLF such as fluorescence lifetime, absorption cross section, emission cross section and gain in the 78-300 K range. We will then discuss the in situ optical temperature estimation methods that could be used to accurately estimate Yb:YLF crystal temperature. Later, we will review our recent lasing/amplification results with room temperature (RT) and cryogenic Yb:YLF systems, where we have achieved output powers exceeding 500 W in cw operation with efficiencies approaching 80% and pulse energies above 300 mJ at 10 Hz repetition rate.