Method for measuring multiphoton absorption cross sections of laser pulses in gases by means of a spectrophone

A technique to measure cross section of multiphoton absorption of laser pulses in gases using photoacoustic detector with time resolution of signals (a spectrophone) has been developed. The efficiency of the technique was tested on the example of single-photon and three-photon absorption of nanosecond pulses of quasimonochomatic radiation with a wavelength of 266 nm by molecular oxygen.