Picosecond measurements using photoacoustic detection

We report experimental results on picosecond time-resolved photoacoustic measurements of excited-state lifetimes, cross sections, and polarization properties for organic dye molecules in solution, using a new technique in which we detect the total photoacoustic impulse produced by two ultrashort optical pulses with variable time delay between them. The picosecond photoacoustic detection technique reported here appears to be a promising new way to observe weak excited-state cross sections and to perform picosecond lifetime measurements in a large variety of weakly absorbing and/or nonfluorescing atomic and molecular systems.