Synthetic spatial coherence function for optical tomography and profilometry: influence of the observation condition

Abstract

We address the basic issue of the observation condition in a synthetic coherence function applied to optical tomography and profilometry, which has not been made clear in previous papers. We present a more general theory for interference fringe formation for spatial coherence control with a synthetic source. The generalized theory predicts the existence of the observation condition that can make the measurement insensitive to the tilt of the object, which will open the new possibility of measuring objects with rough surfaces. We present experimental results that quantitatively verify the validity of the principle and the prediction.

Interferometric spatial coherence tomography: focusing fringe contrast to planes of interest using a quasi-monochromatic structured light source

“…Prior work exists [15][16][17][18][19][20][21][22][23]. Nevertheless, we contribute a new intuitive explanation of the working principle, a novel realization of the light source, and illustrative quantitative measurements of the topographies of both surfaces of transparent flats accessed from one side only.…”

“…To generate such a pattern, Rosen and Takeda [15], Wang et al [16,17], Duan et al [18][19][20][21], and Liu et al [22] used slides and spatial light modulators illuminated by diffused light. We generate the pattern with the interferometric setup shown schematically in Fig.…”