Broadband on-chip photonic spin Hall element via inverse design

Abstract

The photonic spin Hall effect plays an important role in photonic information technologies, especially in on-chip spin Hall devices. However, conventional devices suffer from low efficiency or narrow bandwidth, which prevents their practical application. Here, we introduce a spin Hall device using inverse design to achieve both high efficiency and broadband. Spin-dependent light separation is enabled by a 2.4 μm circular device with 100 nm pixels. The photonic spin Hall element is fabricated on a silicon-on-insulator wafer compatible with a standard integrated photonic circuit. The spin light is detected and emitted with an efficiency of up to 22% and 35%, respectively, over a 200 nm bandwidth at optical wavelength.