Experimental evaluation of a pyroelectric detector linearity used for pulsed laser energy absolute measurement

The linearity of a pyroelectric detector used for pulsed laser energy absolute measurement has been studied using an experimental evaluation. Two different methods were used to evaluate the detector linearity: by comparison to a calorimeter and using the inverse square distance law. Different detection substrates were used and tested. A heating material in the form of a thin film was integrated into the substrate. This material is not only absorbent to transform laser energy into heat but also electrically resistive to transform the electric energy delivered by a current pulses generator into heat by Joule effect. An original approach based upon an electric substitution method has been used to measure the pulses energy given by the laser system and not the pulses mean power as it is commonly used. The measurement method is then based upon the comparison of the maximum voltage responses which are proportional to the pulse energy.