Photographic recording of YAG:Er3+ laser radiation (λ=2.94 μm) by thermal sensitization of the emulsion

A study was made of the possibility of using thermal sensitization of a silver halide photographic emulsion for recording YAG:Er³⁺ laser radiation (λ = 2.94 μm). Using an FT-101 photographic film it was possible to record the radiation down to energy densities of ~ 1 mJ/cm² in a dynamic range of ~ 100 with a resolution of at least 50 lines/mm when the laser pulse duration was ~ 150 μsec. This method was employed to determine for the first time the spectral width of a line emitted by a YAG:Er³⁺ laser operating in the free-running regime.