A new technique for determination of the spatial distribution of polarization in polymer electrets

A new method for measuring the spatial distribution of polarization in poled polymer electrets has been developed. The technique, called the Laser Intensity Modulation Method (LIMM), is based upon measurement of the pyroelectric current generated by the electret when it is heated with a laser beam which is intensity-modulated at frequencies varying from 100 Hz to 100 kHz. A special analytical technique is used to transform the current-frequency measurements to spatial distributions. The method gives high resolution and is very stable with respect to measurement errors. The technique can be easily implemented in a laboratory with conventional equipment. Experimental results on a number of samples are presented.