Fig. 4: Measurement of the SHEL at 800 nm.
a Schematic of Stokes polarimetry set-up. HWP: half-wave plate, L: lens, QWP: quarter-wave plate, LP: linear polarizer, CCD: charge-coupled device camera. b Phase difference between ts and tp, c \({\delta }_{H}^{+}/\lambda\), d \({\delta }_{V}^{+}/\lambda\), e ϵH, and f ϵV. Curve: simulated, markers: measured. Insets in c, d show the magnified view for near-normal incidence where the analytic formula (solid) given by Eq. (1) deviates from the exact shifts (dashed) due to the breakdown of the assumption, i.e., \({(2\pi w/\lambda )}^{2}\gg {\cot }^{2}{\theta }_{i}\). Error bars of the measured data are not shown because they are all smaller than the markers.
