Laser optical ultarasound detection using two interferometer systems

摘要

A laser ultrasound detection technique which is insensitive to laser intensity fluctuations, perturbation at the object surface and the like is disclosed. The invention consists of two substantially identical interferometers of the Fabry-Perot type or such an interferometer with a birefringent element in its optical cavity. The interferometers have resonance frequencies higher and lower than the laser frequency so that noises can be cancelled out by signal processing.