Fig. 3

Calculated transverse-spin states of all designed devices and SEM images of fabricated device WG_6–8. a Calculated transverse-spin states in the evanescent region of all eight sample devices. b SEM image of the device WG_6–8. The inset shows a close-up of the coupling section between the access waveguide and the resonator. c Top: junction point of the tapered coupler consisting of a tapered SiN _x waveguide and a SU8 waveguide. Bottom: cross-section views at various positions of the tapered coupler. The minimum width of the SiN _x taper (shown in the right-hand side image) is 130 nm