Integrated interferometer for monitoring three-dimensional vibrations by discrete aperture

This paper presents a new method for measuring vibration based on interference from two spherical waves. By integrating the two interference arms into a beamsplitter cube by reflective film and dividing the probe beam into two parts with discrete apertures, the interferometer can distinguish that the vibrations are from the monitored optical components or from laser interferometer system itself. At the same time, because the two interference waves are spherical, it can realize monitoring the three-dimensional vibrations. The measurement system has advantages of being stable and reliable with an integrated structure. Theoretical analysis and experimental demonstration are performed. The experiment results indicate that the method can monitor three-dimensional vibrations accurately.

► We propose a new coating design and divide the measurement path into two parts.
► The use of two spherical waves realizes the three-dimensional measurement.
► The two discrete apertures distinguish the sources of the fringe changes.
► The integrated structure is stable and the experiments show the method is feasible.