Piezoelectric detection of optoacoustic spectra at cryogenic temperatures: neodymium hydroxide below 10 K

The first piezoelectric detector for pulsed dye laser-excited optoacoustic spectroscopy of powders at cryogenic temperatures is reported. High-resolution f-f spectra of neodymium hydroxide below 10 K are presented to demonstrate its utility. Spectral simplification due to depopulation of upper Stark components of the ground state as well as significant line narrowing is observed relative to the room-temperature spectra.