Accumulated Photon-Echo Measurements In Ruby under Hydrostatic Pressure

Photon-echo techniques are widely applied nowadays to study optically active ions in solids. The first photon echoes were observed for the R1 transition in ruby (Al2O3: Cr3+) by Kurnit et al1 using the high-power pulses of a ruby laser. Very recently,2 phase relaxation of both the R1 and R2 transitions in ruby was studied at 1.5 K and ambient pressure. Here, use was ma.de of the technique of accun1ulated photon echo,3 which despite the low average laser power offers greatly enhanced detection sensitivity by virtue of the high repetition rate.