title: Opaque optics thickness measurement using a cyclic path optical configuration setup and polarization phase shifting interferometry.
abstract: Thickness measurement of an opaque optics using a cyclic path optical configuration (CPOC) setup and polarization phase shifting interferometry (PPSI) is presented. The CPOC setup is used to simultaneously focus two orthogonally polarized counterpropagating converging beams at its hypotenuse arm. The opaque optics is placed at the hypotenuse arm of the CPOC setup such that one of its surfaces reflects back one of the counterpropagating focusing beams. Because of the thickness of the opaque optics, the other focusing beam suffers a longitudinal shift in the beam focus. Applying PPSI, the longitudinal shift in the beam focus which is twice the thickness of the opaque optics is determined. The results obtained for a silicon plate of thickness 0.660 mm with a measurement uncertainty of 0.013 mm are presented.
authors.affiliation: Department of Atomic Energy, Raja Ramanna Centre for Advanced Technology, Government of India, Indore 452013, India. ypk@rrcat.gov.in
authors.forename: Y Pavan
authors.initials: YP
authors.lastname: Kumar
authors.forename: Sanjib
authors.initials: S
authors.lastname: Chatterjee