Observation of photon echo in Er 3+ :YAG at 1.527 µm

We report what is to our knowledge the first experimental observation of two- and three-pulse echoes in Er3+:YAG at 1.527 µm. The experiment was performed on the transition from the I415/2 ground state to the lowest Stark level of the I413/2 excited state. The corresponding homogeneous dephasing time was measured to be approximately 50  ns at 1 and 7  K. In addition, three-pulse echo decay indicated a lifetime of the spectral grating of ∼30 µs. Implications of these results for optical data storage and optical signal processing are discussed.