Harmonic calibration of quadrature phase interferometry

Phase shifter calibration in phase-shifting interferometry.

This paper describes some practical methods to calibrate the phase shifter in phase-shifting interferometry (PSI). The phase shifter used in the experiment is a piezoelectric transducer (PZT) that has a nonlinearity of <l%. Using the quantitative method described in this paper, the repeatability in the measurement of the phase-shifting angle is ̃9.046 rms, and the 3σ value is 0.139. A calibratio...

Tropospheric Phase Calibration in Millimeter Interferometry

We review millimeter interferometric phase variations caused by variations in the precipitable water vapor content of the troposphere, and we discuss techniques proposed to correct for these variations. We present observations with the Very Large Array at 22 GHz and 43 GHz designed to test these techniques. We find that both the Fast Switching and Paired Array calibration techniques are effecti...

Quadrature wavelength scanning interferometry.

A novel method to double the measurement range of wavelength scanning interferometery (WSI) is described. In WSI the measured optical path difference (OPD) is affected by a sign ambiguity, that is, from an interference signal it is not possible to distinguish whether the OPD is positive or negative. The sign ambiguity can be resolved by measuring an interference signal in quadrature. A method t...

Quadrature Component Analysis for interferometry

This work presents a generalization of the Principal Component Analysis (PCA) demodulation approach that is renamed as Quadrature Component Analysis. We show a new and general mathematical analysis of this demodulation algorithm and we demonstrate that this method is not affected by the number of fringes limitation. Additionally, we show that any asynchronous phase-shifting demodulation method ...

Collinear phase matching for second harmonic generation using conoscopic interferometry