  In this article, we report the first observation of nanosecond laser induced
transient dual absorption bands, one in the bandgap (TA1) and another in the
sub-bandgap (TA2) regions of a-Ge5As30Se65 thin films. Strikingly, these bands
are thermally tunable and exhibit a unique contrasting characteristic: the
magnitude of TA1 decreases while that of TA2 increases with increasing
temperature. Further, the decay kinetics of these bands is strongly influenced
by the temperature, which signifies a strong temperature-dependent exciton
recombination mechanism. The induced absorption shows quadratic and the decay
time constant shows linear dependence on the laser beam fluence.
