Formation of holograms at the wavelength of 2.76 μ and measurement of the width of the emission line of a CaF2:Er3+ crystal laser by a holographic method

An experimental investigation was made of the possibility of holographic use of a CaF₂:Er³⁺ crystal laser emitting at the wavelength of 2.76 μ. The system used consisted of a CaF₂:Er³⁺ master oscillator, a threepass amplifier, and a holographic system in the form of a Mach–Zehnder interferometer. Holograms were recorded in MnBi films by indirect heating to the phase transition temperature using IFP-1200 flashlamps. Holograms of a grid with a period of 1 mm and of a scatterer made of fluorite were obtained. Young interferograms were recorded in a MnBi film when the path difference between the reference and object beams ranged from 0 to 80 cm. This indicated that the width of the CaF₂:Er³⁺ laser emission line did not exceed 1/80 cm^–1 and the laser could be used in recording holograms of objects with a depth of field of at least 80 cm.