MICHELSON INTERFEROMETRIC DETECTION FOR OPTOACOUSTIC SPECTROSCOPY

We have described a Michelson interferometeric optophone which can be used as a sensitive microphone. A Michelson interferometer is constructed with a pellicle beam splitter attached on the wall of the optoacoustic cell. Periodic variation of the pressure inside the cell alter the path difference of the reflected beams, thereby changing the optical interference pattern. The optoacoustic signal can be detected by monitoring the change in the intensity of the interference fringe. This method shows a linear response to small signals and a comparable sensitivity to the conventional microphone.