  IR induced piezo optic effect (POE) in PbTe:Ca crystals was found under the
influence of nanosecond pulse CO2 laser with a wavelength of 10.6 micro meters.
It was shown that addition of Ca leads to an increase of the POE tensor
coefficient. This indicates the appearance of enhanced IR induced static dipole
moments caused predominately by Ca impurities. Simultaneously, the variations
in time kinetics for the POE in nanosecond time regime were explored. A
substantial role of electron phonon subsystem in the observed POE effect was
demonstrated. The studies were done both for diagonal as well as off diagonal
POE tensor components.
