Wavelength scanning confocal interference microscope for separate measurement of refractive index and geometrical thickness

We previously proposed a system based on a combination of a confocal microscope and a wavelength scanning heterodyne interferometer, for separate measurement of refractive index and geometrical thickness of lens and plates. However, we used two optical systems successively although they share the same optical system. In this paper, we propose a new measurement scheme which enable us to measure both the confocal profile and the optical path difference of the interferometer by single scanning of an object. We describe herE the measurement principle, the apparatus, signal processing means, and some experimental results.