Abstract

Applications of controlled laser fields (phase shifted pulse sequences, shaped laser pulses, coherent multiple-frequency irradiation) to prepare useful molecular states or alter molecular dynamics have been extensively explored both theoretically and experimentally over the last few years. To date, however, most of the experimental demonstrations have simply enhanced signals or modulated overall dissociation rates. We will survey this work (including our own contributions) and compare it with the theoretical promise of selective bond breaking, climbing anharmonic vibrational ladders, orienting molecules, suppressing relaxation, and altering reaction pathways. There are several important reasons for the gap between theory and experiment, but the most important is robustness—many proposed experiments are too sensitive to experimental inhomogeneities or imperfect knowledge of the molecular Hamiltonian to be implemented in the laboratory. Imposing robustness by frequency modulation provides an extremely robust approach to preparing population inversions, generating quantitative transfer between states, and modifying relaxation rates. Experiments with frequency swept laser pulses amply verify that even simple, poorly controlled waveforms can produce useful molecular states.

© 1992 Optical Society of America