Abstract

If a narrow-band laser is tuned in to the Doppler broadened absorption profile of an optical transition in a low-pressure gas, velocity-selective excitation is achieved. This creates fluxes of excited molecules parallel or antiparallel to the k-vector. Small objects (such as aerosol particles) suspended in the gas will now be bombarded by excited molecules, either from the illuminated side or from the “dark” side, depending on the sign of the laser detuning. If the molecules deexcite on the object's surface while releasing a portion of the excitation energy in the form of kinetic energy, the resulting superelastic collision will produce a recoil on the object by momentum conservation.¹

© 1994 IEEE