Figure 2
(a) Calibration of optical path delay \(\Delta D\) vs rotation angle \(\theta\) for t = 140 μm and n = 1.516. Solid line is theoretical curve using Eq. (4) and experimental data corresponds to minima values of He–Ne laser interferogram. (b) Experimental data showing self-calibrated picoscale resolution from bright to dark fringe tuning. The intensity variation near zero position is attributed to the various noises in the interferometer.
