Simultaneous and Quantitative Spin and Orbital Angular Momentum Detector

We design a simultaneous and quantitative spin and orbital angular momentum (SAM/OAM) detector, which is rather compact only with orthogonal nanoslit pairs etched on a silver film. Based on the surface plasmon polariton wave excited on this device surface, SAM of ±1 can be distinguished according to the focal position; while OAM of ±1 can be determined according to the focal intensity. Moreover, the device works well with rather wide spectral range of ~250 nm, and the ratios of each light components can be quantitatively estimated. Considering its compact configuration, wide working spectral range, simultaneous and quantitative SAM/OAM detection capability, it is believed the proposed detector can be implemented in photonic circuits.