The photoelastic effect evaluation by means of photothermal deflection technique

The collinear configuration of the photothermal deflection technique is applied here to evaluate the influence of the photoelastic effect in the refractive index variation. The measurement procedure is based on analysis of the phase signal linear decay as a function of the distance between the beams. By comparing lateral scans obtained for different polarization states of the probe beam, it is possible to derive the relative influence of the two mechanisms (opto-thermal and photoelastic) responsible for deflecting the probe. Experimental results obtained for a glass sample which validate the proposed method are also shown.