Examples of single-shot superimposed profiles, (a)–(c) with a near-zero delay and (d) with a delay far from zero. Each scale bar represents 100 µm. The angular deviations (αx, αz) for panels (a)–(c) evaluated with equation (1) are (2.0, 0.11), (1.7, −1.0) and (2.5, −2.1) µrad, respectively. The fringe profile shown in panel (d) originates from parasitic scattering from the edge of the BS and/or BM. (e) Line profile along the dashed line in panel (c) (symbols) and its low-pass filtered profile (black line). (f) Oscillatory component of the measured line profile (symbols) and a fitted cosine curve (blue line) with a fringe spacing δz of 60.0 µm and visibility V of 0.31. The fit is performed with a region in which the modulus becomes a maximum (near position 0 in this case). The fitted function multiplied by the low-pass filtered profile is also shown in panel (e) (blue line).