Laser coherent control of quantum dynamics at the CSIR: NLC

Abstract

Coherent control of quantum dynamics in optical, molecular and biological systems is a rapidly advancing field with many possible applications. This field of study was originally motivated by the goal of steering photoreactions into specific reaction channels. The principle used is controlled interference of the quantum wave functions via time domain shaped ultra-short pulses. The time/frequency product of a pulse is a constant, determined by Heisenberg’s uncertainty principle, therefore, a short time pulse results in a pulse that has a broad frequency bandwidth. In addition, there is a fixed phase relation between the various frequency components that constitute the pulse. Time domain beam shaping allows the modification of the phase and amplitude in the frequency domain of the Fourier transform that constitute the pulse and then transforming back to the time domain. This has the effect of shaping the pulse in time. Various techniques of laser coherent control exist, but they all depend on manipulating the phase and amplitude of the laser pulse, which controls the quantum dynamics via the interference of the quantum wave functions. This paper will give an introduction to coherent control, specifically with regards to optical, molecular and biological systems, as well as an overview of the various coherent control experiments at the CSIR National Laser Centre (NLC).