Phase Shifting Interferometry Techniques for Surface Parameters Measurement

Abstract

This chapter discusses the temporal phase shifting interferometryPhase shifting interferometry (PSI) methods developed at the Karpenko Physico-Mechanical Institute of the NAS of Ukraine. The two-stepTwo-step interferometry method with an unknown phase shiftUnknown phase shift of the reference waveReference wave is analyzed. In this method, the extraction of the unknown phase shiftUnknown phase shift is fulfilled using the population Pearson correlation coefficientPopulation Pearson correlation coefficient (PPCC). This method allows extraction of both 3D surfaceSurface nanoreliefNanorelief and 3D surfaceSurface macrorelief, including 3D wavinessWaviness and form. However, the high error level in the retrieved phase mapsPhase map induced the creation of an iterative method of two-stepTwo-step interferometry with the unknown phase shiftUnknown phase shift. To speed up the interferogramsInterferogram recording and remove the reference and object wavesObject wave registration, a method of three-step interferometry with unknown phase shiftsUnknown phase shift is proposed. In order to expand the range of surfaceSurface roughnessRoughness reconstruction, the two-stepTwo-step dual-wavelength interferometryDual-wavelength interferometry method (TS DWIM) was elaborated. In this method, only two pairs of interferogramsInterferogram are generated and each pair is differed only in an arbitrary phase shiftArbitrary phase shift of the reference waveReference wave. Since the method does not require phase shiftPhase shift calibration, it is enough to use only one arbitrary phase shiftArbitrary phase shift to record both pairs of interferogramsInterferogram. The three-frameThree-frame two-wavelength interferometry method with unknown phase shiftsUnknown phase shift between interferogramsInterferogram is similar to the TS DWIM. However, it does not require additional recording of the object and reference wavesReference wave, which significantly increases its performance.