High performance chirality-distinguishing beamsplitter based on the dielectric-metal hybrid waveguides

Chirality of photons plays an important role in light-matter interaction, however, efficient and broadband chirality distinguition in the photonic integrated circuits (PICs) is a great challenge. In this Letter, a novel chirality-distinguishing beamsplitter (CDBS) based on the dielectric-metal hybrid waveguides is proposed. It consists of an integrated polarization converter and a polarization beam splitter (PBS). Left-handed and right-handed circularly polarized (LCP and RCP) light are first respectively converted into the orthogonal fundamental transverse-electric and transverse-magnatic transverse-magnetic ​ modes in an integrated polarization converter, which are then split to different output channels of a PBS. Our CDBS shows the advantages of one of the lowest insertion losses (<1.3 dB), a small footprint (11.6 × 2 ×2μm³), a broad operating bandwidth (1.45–1.65μm) and one of the highest chirality isolations (>11.7 dB) between the LCP and RCP light. In addition, the proposed device can be used for emitting photons with a selective spin angular momentum due to the reciprocal transmission of light. Our device offers robust functionality of circularly polarized light distinguition and generation by using PICs, and has potential applications in nanophotonics, biology and quantum information processing.