Fig. 2: Design of the device with taking non-radiative loss into account.
From: Observation of spatiotemporal optical vortices enabled by symmetry-breaking slanted nanograting
a By adding an optical extinction coefficient to the material (kSi = 0.0065) to represent non-radiative losses, the topological singularity of the transmission coefficient does not vanish but deviate to an off-Γ position in ω-kx space. b The evolution of the topological singularity in ω-kx space when the slant angle of grating θ varies from 30° to 2°. c The corresponding complex transmission coefficient distribution in the frequency-momentum space for slant angles θ = 10°, 15°, and 20°. d The amplitude and phase distribution of the transmitted STOV in the spatiotemporal domain after a Gaussian pulse propagates through the nanograting with the slant grating angle of θ = 15°.
