Photothermal transformation of color centers in CaF2 crystals

Photothermal transformations of color centers in additively colored calcium fluoride crystals and in a colored crystal with a recorded hologram have been investigated. It is shown that the absorption spectrum of a colored crystal can be reconstructed within the entire transparency range of the matrix crystal by varying both factors affecting the sample—actinic radiation wavelength and temperature—as well as the duration of their effect. This possibility is important for the application of additively colored CaF2 crystals as a holographic medium.