CERTIFYING A GONIOMETRIC DEVICE BY MEANS OF A ROTATING GLASS WEDGE

This paper discusses the relationships between the variation of the an gular position of a glass wedge with a small refractive angle and the variation of the angular position of a ray coming out of the wedge. Ca lculations are given to show how errors in measuring the angle of the wedge, its rotation angle, and the refractive index of the glass from which it is fabricated affect the measurement error of the angular dis placement. It is shown that, with very moderate requirements on the me asurement accuracy, errors of specifying the angle of only thousandths of an are sec can be achieved. (C) 1997 The Optical Society of Americ an. [S1070-9762(97)00609-X].