Investigation of damage induced in crystals by radiation from a CaF₂:Er³⁺ laser (λ = 2.76 μ)

G. V. Gomelauri, A. A. Manenkov


Abstract: Laser-induced damage was investigated in a number of alkali halide and other crystals at λ=2.76μ, using a CaF₂:Er³⁺ crystal laser (with a pulse duration of 85 nsec). The results obtained at various temperatures for the NaCl specimens with the highest optical strength are compared with the data from measurements at other wavelengths and are discussed in terms of the avalanche-breakdown mechanism. It is found that the measured threshold for λ=2.76μ at 300°K, together with the data previously obtained for λ=10.6, 1.06, and 0.69μ, are satisfactorily explained by the avalanche-ionization theory using a value for the effective electron-phonon collision frequency of ν_eff = 6×10¹⁴ sec^–1, but the theory does not explain the temperature dependence of the damage threshold observed at λ=2.76μ.

UDC: 539.2

PACS: 61.80.-x, 42.60.He

Received: 26.12.1977

 English version: Soviet Journal of Quantum Electronics, 1979, 9:1, 23–25