Silicon microelement vibration testing using conventional and heterodyned time-average interferometry with automated temporal and spatial phase stepping

This paper focuses on the applicability of the temporal (TPS) and spatial carrier (SCPS) phase-shifting techniques to the time-average interferogram intensity modulation distribution determination. Both techniques use the same mathematical formulae, but in different domains: temporal and spatial ones. They are sensitive to different types of errors. The influence of main experimental errors: phase-step miscalibration, spatial carrier miscalibration, average intensity changes and intensity noise in both the presented techniques on the fringe function determination (|J0| or J02 in case of sinusoidal vibrations), is discussed. The techniques are compared to find the most appropriate one. The time-average technique with heterodyning for small vibration-amplitude measurements is also discussed. The application of the SCPS method to this technique is shown for the first time.