Spatial Coherence Interferometry and Its Applications.

摘要

Interferometry is a family of techniques that have been widely used for testing optical components and optical systems. The human eye is a sophisticated optical imaging system in nature. To characterize the surface profiles of its optical elements and the optical properties of media in the system helps the understanding of the optical design of the human vision system, which remains a challenging and intriguing research area. This dissertation proposes a new interferometric technique, operating by the principle of spatial coherence, for this purpose to overcome the measurement limitations experienced by existing methods. The studies consist of both theoretical aspects and applications of this technique, termed as spatial coherence interferometry.;Two mathematical models are developed, forming the theoretical basis. One is a physical optics model that computes wave propagation and the resulting interference signals. The other, on the basis of paraxial raytracing, is a simple but effective tool for understanding the distribution of the angular spectrum. A benchtop system is built and used to perform proof-of-principle experiments in optical sectioning. With the physical constraints in this real system, two system models are presented and compared to experimental results. Besides the original intended ophthalmic applications, the spatial coherence interferometry is found to be useful in many general optical testing applications, including absolute thickness / distance, absolute refractive index and surface profile, for single- and multiple-layer samples. The dissertation explores each of these applications by discussing the measurement principle, experimental results and uncertainty analysis, and suggesting future improvements. As the other part of the research aiming to enhance the understanding of the optical design of the human visual system and of the effects of aging on the optical system in the human eye, an age-dependent eye model featuring a GRIN lens with refractive index distribution of a high-order polynomial function is constructed. The GRIN coefficients, as variables in optical design of the human eye, are found to be effective in explaining the aging effects and correcting high-order aberrations for the eye.