PHOTOACOUSTIC MAPPING OF THE AMPLIFICATION REGION AND CHARACTERIZATION OF A DYE-LASER AMPLIFIER

Mapping of the amplification region and full characterization of a dye laser amplifier by means of a photoacoustic technique are presented. The acoustic signals generated in the pumped medium as a consequence o f nonradiative transitions are gain dependent. We use the ratio betwee n the acoustic signal measured when the oscillator beam passes through the amplifier, to the acoustic signal when it is blocked, as a figure of merit of an amplifier stage. By using the oscillator beam as a spa tial probe of the amplifier gain region, it is possible to map the opt ically inverted medium, assigning a photoacoustic ratio to each point of the medium. (C) 1996 American Institute of Physics.