Investigation of Density Perturbations in Molecular Nitrogen Formed by Pulsed Optical Lattices

摘要

A complimentary experimental/numerical investigation on the effect of counter-propagating pulsed lasers on molecular nitrogen was conducted. The experiment verified published theoretical predictions of the effect of laser intensity and gas pressure on the magnitude of induced density perturbations in the gas using a coherent Rayleigh-Brillouin scattering technique. The investigation further verified the use of a modified version of the SMILE DSMC code for more robust prediction of the effect of a non-resonant pulsed optical lattice on a neutral gas. The ambient pressure of molecular nitrogen was varied from 100 torr to 760 torr, and the pump laser energy was varied from 2 mJ to 25 mJ per pulse. The resulting scattered signal from the experiment was measured and compared with numerical predictions. Assuming that the signal of the experiment is proportional to the probe intensity and the square of the density perturbations induced by the pump lasers, the results of the experiment qualitatively support both theoretical predictions and numerical simulations.