the invention uses a heterodyne interferometer with coherent detection that uses a vibrating sample that can be used as a non - contact and non - destructive surface profiler and mapping apparatus where detailed profiles of the local slope and / or roughness of the vibrating sample are obtained in three dimensions . the invention can operate in either a heterodyne or homodyne regime with a probe that uses either i ) focused optics , ii ) a single mode optical fiber with an integral grin lens at its far end for focusing onto the sample or iii ) a single - mode optical fiber with a taper at the end . additionally , the heterodyne interferometry technique can be used for imaging birefringent objects such as semiconductor diagnostics of gaas , ingaas , ingaasp , and other ii - vi of iii - v binary , ternary , and quaternary materials for analysis and diagnostics by using the birefringent properties of the object , and monitoring the electrical activity of biological cellular tissue .