Abstract

Tunable picosecond and femtosecond mid-infrared light sources make possible a range of experiments on surface adsorbates and carriers in semi- conductors. For example, time-resolved IR experiments on the picosecond time scale have provided new information on the energy flow and dephasing of CO vibrations on metal surfaces. We will discuss several high-repetition rate generation and detection schemes that can be used to perform these types of experiments. The high-repetition rate experiments (1 kHz, 76 MHz) are compatible with low signal lock-in modulation and do not substantially alter the vibrational populations of the species under study. Coherent transient studies of CO on Cu[111] using IR pulses as short as 280 fs will be presented, and ongoing two- color pump-probe IR experiments in the same system will also be described.

© 1992 Optical Society of America