Simultaneous measurement of two parameters of the spherical lens by low-coherence interferometry

To measure different parameters of a spherical lens simultaneously, a method by low-coherence interferometry with a low temporal coherent light source is proposed. This proposed method can obtain both the radius of curvature and the central thickness of a spherical lens in a single optical system. Owing to the property of low temporal coherence, the contrast of interference fringe pattern, hologram, varies with the optical path difference of an object beam and a reference beam. This enables the central thickness of the test lens to acquire with a Michelson interferometer. Simultaneously, the spherical shape of the test lens, namely the radius of curvature, can be obtained from a hologram which contains information of the wavefront curvature from the reflected beam of the spherical surface of the test lens.