Picosecond Photon Echoes Stimulated from an Accumulated Grating

Abstract

It is shown that in optical transitions with a bottleneck, a mode-locked cw dye laser may be used to generate and heterodyne detect picosecond photon echoes. These echoes are stimulated from an accumulated grating in the electronic ground state formed by a train of twin excitation pulses of constant phase difference. In the zero-phonon transition of pentacene in naphthalene at 6026.8 \AA{} the bottleneck is identified and these echoes are used to determine the dominant dephasing process.