Design and fabrication of confocal fabry-perot interferometers used in laser-ultrasonic detection

The main optical parameters of Confocal Fabry-Perot Interferometers (CFPI), including free spectral range, minimum resolvable frequency difference (instrumental bandpass), finesse, spectral resolving power, were discussed. According to the requirement and feature of laser-ultrasonic detection, a CFPI used in laboratory was designed and fabricated. The CFPI's cavity length and operation point were controlled by a micro-single computer. Laser-ultrasonic non-contact detection is carried out successfully with the CFBI.