Thickness and index measurements of a transparent specimen by full-field optical coherence microscopy

We present the method measuring the thickness and the refractive index of a transparent specimen at a same time based on full-field optical coherence tomography. As a sample a small drop of epoxy was placed on a flat plate and the high-resolution depth resolved en-face images of the epoxy drop were taken. With adopting the plate surface as a reference plane, the physical thickness and the refractive index distribution could be obtained. Owing to the full-field imaging capability, we could obtain the transverse distributions of the thickness and the refractive index without any transverse scanning. The measured thickness at the center of the sample was 24 mu m and the average index was 1.4055 with the standard deviation of 0.0002.