Figure 4
Schematic of the step measurement and captured images. (a) Experimental setup for the step measurement. Interferometer setup is shared with setup shown in Fig. 2a. BE: beam expander and CL: cylindrical lens. Grating: diffraction grating, 600 line/mm. (b) Captured spectral interferometric images by InGaAs camera at each delay position (number in each image, in µm unit). The images were processed so that the contrast was enhanced, and the horizontal and vertical directions of each image represent the wavelength and beam positions. Black dashed lines in each image are guide for eyes indicating area of steps A and B. (c) Zoomed image is at a delay position of 960 µm. To obtain longitudinal heights for steps A and B, 36 horizontal cross-sectional lines between upper and bottom white lines and central red dashed line were analysed. Horizontal yellow dashed lines indicate central area in the regions of steps A and B.
