Holographic motion picture by Eu^3+:Y_2SiO_5

Abstract

Real-time recording of a moving object was made with persistent spectral hole burning of a cryogenic Eu³⁺:Y₂SiO₅ crystal. In a basic holographic configuration the ultrastable laser frequency was continuously scanned within the ⁷F₀–⁵D₀ absorption line (typically 200 MHz in 20 s) while the object was in motion, thus permitting the storage and reconstruction of the moving image. The success of this motion picture is attributable to (1) the kilohertz-wide hole width, (2) the quasi-persistent hole lifetime, and (3) the high hole-burning quantum efficiency of this material.