Yb-doped yttrium lithium fluoride (Yb:YLF) crystal

opticallaser

Crystal structure Tetragonal Point group I41/a Lattice parameters а = 5,164 Å, c = 10,741 Å Thermal expansion 4×10-6 / ºC Thermal conductivity 4,36 W/mK Density 3,95 g/cm³ Mohs’ hardness 5 Melting temperature 825 ºC Transmission range 0.2-5 μm Refractive indices (λ=1.06 μm) no = 1,448, ne = 1,470 dno/dT -2,0×10-6 / ºK dne/dT -4,1×10-6 / ºK Fluorescence lifetime 2.1 ms Emission cross section 7.5x10-21 cm² @1017nm, E//c Emission bandwidth 60 nm Absorption cross section 10.6x10-21 cm² @959 nm, E//c The Yb-doped material has the highest quantum efficiency (>90%) among commercial laser materials. Yb:LiYF4 (Yb:YLF) have wider emission spectra than Yb:YAG, which is necessary for the generation and amplification of ultrashort pulses. A YLF host crystal has higher thermal conductivity than glass, resulting in negligible lower thermal lensing. The YLF crystal also has the capability of a high degree of doping with ytterbium ions.