Photoacoustic spectroscopic studies of Ho3+, Er3+, and Sm3+ doped polyvinyl alcohol films

Abstract

Photoacoustic (PA) spectra of Ho3+, Er3+, and Sm3+ doped PVA films were obtained in 350–800 nm range. PA spectra were also obtained for the respective dopant oxides: Ho2O3, Er2O3, and Sm2O3 for comparison. It was found that in PVA the PA sensitivity has increased considerably compared to pure rare earth oxides. The relative intensities of absorption bands at 540 and 637 nm of Ho3+: PVA have shown distinct enhancement, indicating the increase in nonradiative relaxation at these excitations. Furthermore, the PA signals at wavelengths for different PA absorption bands were monitored as a function of chopping frequency. These experiments have shown that PA signal varies w−1 both for oxides and PVA samples, suggesting that they behave as thermally thin samples. © 1997 John Wiley & Sons, Inc.