Simultaneous acquisition of photoacoustic and fluorescence spectra at high sensitivity from powdered samples at...

An apparatus has been built for simultaneous high-sensitivity photoacoustic and fluorescence studies at temperatures from 4 to 295 K that uses a pulsed tunable dye laser as the excitation light source. A powdered sample, pressed into the pellet, is attached to a coiled fused-silica rod that provides thermal isolation from and good acoustic contact to an ambient temperature acoustic detector. The surface of the rod is roughened, thereby eliminating acoustic interference arising from scattered excitation light. As a test of the apparatus, the absorption spectrum of the (4)F(9/2) state of Nd(3+) in A-phase Nd(2)O(3) powder, dispersed in a KBr pellet, was recorded simultaneously by means of photoacoustic and fluorescence excitation spectroscopies.