Enhancement of photoacoustic emission through terahertz-field-driven electron motions

Abstract

We report the study of enhanced photoacoustic emission from a laser-induced plasma under the influence of the terahertz field up to 100 kV/cm. We theoretically and experimentally investigate the energy transfer from terahertz radiation to molecular translational motion, through terahertz-field-driven electron motion and inelastic electron-molecule collision. The enhanced photoacoustic emission in the frequency range of 1-140 kHz is quadratically dependent on the incident terahertz field. We also demonstrate, as an application, that the enhancement of photoacoustic emission from gases asymmetrically ionized by two-color laser field can be used for coherent terahertz wave detection.