Fig. 4: Chiral photoelectric response.
From: Anapole-state-enhanced 2D chiral photodetector operating in the near-infrared second window
a Calculated mapping image of reflection spectra under LCP and RCP illumination with structural asymmetry Δy. The period is enlarged to P = 1200 nm compared to the structure in Fig. 1. LCP left-handed circular polarizations, RCP right-handed circular polarizations. The blue and the green dashed lines represent the optical resonances excited by the horizontal and vertical field component of the incident light, respectively. Calculated mapping image of reflection spectra with Δy under LCP (b) and RCP (c) illumination. Mirror symmetry is broken by shifting the horizontal groove along x direction, Δx = 50 nm. Measured reflection spectra with Δy under LCP (d) and RCP (e) illumination, Δx = 50 nm. The images of SEM are listed by the side. f The calculated electric field intensity distributions of one unit on the surface of metasurface for the LCP and RCP, at the wavelength of 1550 nm, Δx = 50 nm and Δy = 250 nm. g Top: Measured reflection spectra with Δx = 50 nm and Δy = 250 nm under LCP and RCP illuminations. Bottom: Normalized spectra of fundamental laser (right, 1550 nm) and SHG signal (left, 775 nm) generated from the MoS2/WSe2 heterostructure on Ag metasurface under LCP (orange) and RCP (blue) illumination. h Top: Spectra of responsivity induced by LCP and RCP light. Bottom: The chiral discrimination ratio of the photoelectric response. i Ellipticity angle dependent responsivity polar diagram at the wavelengths of 1550 nm. The data points represent the measured data and the solid line is the smooth connection of the data points.
