Abstract
When a laser spot is focused on a Triglycine Sulphate plate used as a pyroelectric detector, a non-linear response is observed when the illumination is above a threshold of about 40W.cm-2. It appears that the items of primary significance are:(a) weak laser pulses can cause nucleation of domains whose polarization are opposed to the bulk polarization of the crystal.(b) this new process is elastic, polarization recovers at termination of irradition.(c) it can be inhibited by large electric fields.(d) it is time dependent in accordance with heat propagation to a nucleation site and nucleation growth processes of a domain.Application to pyroelectric detectors are considered.