Pulsed photoacoustic spectroscopy (PAS) technique for immediate measuring absolute optical absorption coefficient is presented. It is based on determination of amplitude‐time characteristics of photoacoustic (PA) signal generated in air surrounding the sample under investigation. The PA signal is excited by a short laser pulse. The sample is placed in the lateral chamber of a three‐chamber PA cell. The difference of PA signals excited in two other chambers is recorded. Time dependence of PA signal for each PA cell chamber is derived. The theoretical predictions are experimentally verified. The pulsed PAS technique presented was tested experimentally by measuring water absorption coefficient at an infrared wavelength. ©1996 American Institute of Physics.