Spectral interferometric technique for 3D-shape measurement of microscopic objects with improved resolution, speed of measurement and signal processing

A spectral interference microscope using a superluminescent diode as light source and a liquid-crystal Fabry-Perot etalon as a frequency tunable device is developed for three-dimensional imaging micro-profilometry. By changing the current to the superluminescent diode, constant light input to the interferometer was achieved throughout the measurement. A high speed Fourier transform technique was developed for analysis of the data. It takes few seconds to measure the three-dimensional absolute height distribution of a discontinuous object. Experimental results with improved resolution and speed of measurement are presented.