Accumulated long-lived optical echo and optical memory

An investigation was made of the optimal conditions for the generation of signals of an accumulated long-lived optical echo in an LaF₃:Pr³⁺ crystal (due to the ³H₄–³P₀ resonant transition) with the aim of basing a dynamic optical memory on this echo. The dependences of the intensities of the signals on the number of identical pulse pairs were determined experimentally for the first time and analyzed. An estimate was obtained in the lifetime of a metastable state.