Electronic speckle pattern interferometry: A powerful but underutilized experimental technique

Abstract

Electronic speckle pattern interferometry is a cost effective technique for imaging the deflection shapes of harmonically vibrating objects. The images produced by the interferometer show the vibrating object superimposed with fringes representing contours of equal out of plane amplitude. These images can be used to determine deflection shapes, find and characterize resonances, and ensure the proper placement of sensors. Constructing the interferometer requires only minimal optical expertise, and with slight modifications the interferometer can be made to image static displacement, transient vibrations, fluid flow and thermal effects.Electronic speckle pattern interferometry is a cost effective technique for imaging the deflection shapes of harmonically vibrating objects. The images produced by the interferometer show the vibrating object superimposed with fringes representing contours of equal out of plane amplitude. These images can be used to determine deflection shapes, find and characterize resonances, and ensure the proper placement of sensors. Constructing the interferometer requires only minimal optical expertise, and with slight modifications the interferometer can be made to image static displacement, transient vibrations, fluid flow and thermal effects.