A new technique of wedge angle measurement of a transparent nearly parallel plate (PP) is presented. In this technique, the single-pass angular deviation suffered by a pair of mutually parallel, laterally separated pencil beams is enhanced by using a multipass cavity formed with two right-angle prisms. The resultant angular deflection is converted to linear deviation by means of a Fourier transform lens (FTL), which focuses the pencil beams on to its focal plane. A two-dimensional CCD detector array placed at the focal plane of the FTL measures the linear shift of the intensity centroid (IC) of the resulting Young’s fringes formed due to the superposition of the laterally separated pencil beams. The wedge angle is determined from the measured value of the linear shift of the IC due to the PP.