title: Interferometric measurement of angular motion.
abstract: This paper describes the design and realization of a homodyne polarization interferometer for measuring angular motion. The optical layout incorporates carefully designed cat's eye retroreflectors that maximize the measurable range of angular motion and facilitate initial alignment. The retroreflectors are optimized and numerically characterized in terms of defocus and spherical aberrations using Zemax software for optical design. The linearity of the measurement is then calculated in terms of the aberrations. The actual physical interferometer is realized as a compact device with optical components from stock and without relying on adjustable holders. Evaluation of its performance using a commercial autocollimator confirmed a reproducibility within 0.1%, a non-linearity of less than 1 ppm with respect to the autocollimator, an upper limit to its sensitivity of about 5 × 10(-11) rad/Hz from audioband down to 100 mHz and an angular measurement range of more than ±1°.
authors: School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, United Kingdom. fepa@star.sr.bham.ac.uk
authors: Fabián Erasmo
authors: FE
authors: Peña Arellano
authors: Hasnain
authors: H
authors: Panjwani
authors: Ludovico
authors: L
authors: Carbone
authors: Clive C
authors: CC
authors: Speake