The pulsed photothermal deflection spectroscopy (PTDS) method to deter
mine the large optical absorption coefficient from the transverse PTDS
magnitude and to measure spectroscopic data of optically dense sample
from the normal-to-transverse magnitude ratio of the PTDS signal is p
resented and has been examined both theoretically and experimentally.
Saturation at high absorption, effects of thermal inhomogeneity of the
sample, and energy or power fluctuation of both the excitation and pr
obe beams are avoided by this method. Together with the transverse PTD
S technique, the dynamic range of spectroscopic measurement is over 9
to 10 orders of magnitude. This technique can be used with sample whic
h is transparent or semitransparent to the probe beam.