Excited-state absorption spectroscopy of Nd3+:SrF2 crystals in the 1280 — 1320 nm spectral wavelength range

The excited-state absorption (ESA) in Nd³⁺:SrF₂ crystals was investigated in the 1280 — 1320 nm spectral wavelength range by selective laser excitation. It was found that, on excitation at wavelengths of 743 and 800.5 nm, there is no ESA in the ranges 1304 — 1309 and 1295 — 1297 nm. Weak ESA bands are observed in the 1297 — 1304 and 1309 — 1320 nm ranges and the differential ESA cross section does not exceed 0.3 × 10^–21 cm² . The results indicate that the ESA does not preclude the use of an Nd³⁺:SrF₂ crystal as the amplifying medium in the wavelength range 1280 — 1320 nm.