Optical path

The figure shows the optical path of a Mirau-objective respectively a Mirau-interferometer. Reference beam (4 to 6) and object beam (7) have identical optical path length and can thus cause white light interference.

Optical path (OP) is the trajectory that a light ray follows as it propagates through an optical medium. The geometrical optical-path length or simply geometrical path length (GPD) is the length of a segment in a given OP, i.e., the Euclidean distance integrated along a ray between any two points.[1] The mechanical length of an optical device can be reduced to less than the GPD by using folded optics. The optical path length in a homogeneous medium is the GPD multiplied by the refractive index of the medium.

  1. ^ Bass, M.; DeCusatis, C.; Enoch, J.M.; Lakshminarayanan, V.; Li, G.; MacDonald, C.; Mahajan, V.N.; Van Stryland, E. (2009). Handbook of Optics, Third Edition Volume I: Geometrical and Physical Optics, Polarized Light, Components and Instruments(set). McGraw-Hill Education. ISBN 978-0-07-162925-6. Retrieved 2021-10-11.