Holograms convertible by an incoherent photo-thermal treatment in CaF 2 crystals with color centers

A hologram recorded in CaF2 crystal with color centers changes its nature (amplitude, phase, or amplitude-phase), profile, and diffraction efficiency under the impact of incoherent illumination and heating. The character of the amplitude-phase gratings in this crystal can be either in-phase or antiphase. These cases can be differentiated by analysis of the angular dependencies of the hologram diffraction responses. Owing to the diffusion-drift mechanism of hologram recording, tough photo-thermal treatment does not result in noticeable hologram decay. Incoherent photo-thermal treatment enables the formation of highly stable volume holograms that can be read out in visible, near- and mid-IR spectral ranges. (C) 2014 Optical Society of America