Surface shape measurement for a multilayered object by synthesis ofoptical coherence function

摘要

An interferometric system is proposed by synthesis of the opticalncoherence function for measuring surface shapes of multiple planes in anmultilayered transparent object. By stepwise optical frequencynmodulation of a laser source, the system synthesizes the opticalncoherence function into a delta function-like peak at an arbitraryndepth, and the depth of the peak can be adjusted by changing thenfrequency modulation parameter. In this way, the interference of anreference with the reflection at each target surface can be selectivelynextracted, and the shapes of the target surfaces can then be obtained bynmeans of fringe analysis such as the Fourier transform (FT) method. Annexperimental demonstration is presented and performance degradationnfactors are discussed