Long-term image storage and phase conjugation by a backward-stimulated echo in Pr^3+:LaF_3

Abstract

We have observed spatial-image storage and phase conjugation, using a backward-stimulated echo in a solid sample. The image storage and the delayed phase conjugation were observed to last for at least 15 sec, which is 3 × 10⁵ times longer than the radiative lifetime of the excited state. The backward-stimulated echo produced on the ³H₄–³P₀ transition of Pr³⁺:LaF₃ is found to be a phase-conjugated spatial reproduction of the first excitation pulse. The image storage time depends strongly on the sample temperature.