Abstract

Fast relaxation phenomena of point defects are observed with a pump-probe experimental setup consisting of two rhodamine 6G dye lasers emitting pulses of ~7-ps duration at frequencies resonant with optical transitions of the point defects. A pump pulse excites at frequency ω_L, and a delayed probe pulse (with frequency ω) Interrogates the recovery of the ground state (570 nm ≤ ω_L, ω ≤ 640 nm). The time evolution of the optical density of the ground state is detected as the change in intensity (gain or loss) of the automatically delayed probe after double lock-in demodulation. This detection scheme has a sensitivity of 10⁻⁷.¹

© 1988 Optical Society of America