Optical Power Measurement by using Piezo Microphone

In this study, light power measurement was performed using a piezoelectric microphone with the principle of photo-acoustic effect. The piezo microphone was excited with an 808 nm laser diode modulated by square wave of frequency 20 Hz. The peak-to-peak value of the laser power was set in the range of 0-30 mW. Sensor was linear in this power range and sensitivity of the sensor was found to be 0.023V/W.