Resolving Light Handedness with an on-Chip Silicon Microdisk

The efficient manipulation of circularly polarized light with the proper handedness is key in many photonic applications. Chiral structures are capable of distinguishing photon handedness, but while photons with the right polarization are captured, those of opposite handedness are rejected. In this work, we demonstrate a planar photonic nanostructure with no chirality consisting of a silicon microdisk coupled to two waveguides. The device distinguishes the handedness of an incoming circularly polarized light beam by driving photons with opposite spins toward different waveguides. Experimental results are in close agreement with numerical results, which predict extinction ratios over 18 dB in a 20 nm bandwidth. Owing to reciprocity, the device can also emit right or left circular polarization depending on the chosen feeding waveguide. Although implemented here on a CMOS-compatible platform working at telecom wavelengths, the fundamental approach is general and can be extended to any frequency regime and technological platform

Accurate Transfer of Individual Nanoparticles onto Single Photonic Nanostructures

Controlled integration of metallic nanoparticles (NPs) onto photonic nanostructures enables the realization of complex devices for extreme light confinement and enhanced light–matter interaction. For instance, such NPs could be massively integrated on metal plates to build nanoparticle-on-mirror (NPoM) nanocavities or photonic integrated waveguides (WGs) to build WG-driven nanoantennas. However, metallic NPs are usually deposited via drop-casting, which prevents their accurate positioning. Here, we present a methodology for precise transfer and positioning of individual NPs onto different photonic nanostructures. Our method is based on soft lithography printing that employs elastomeric stamp-assisted transfer of individual NPs onto a single nanostructure. It can also parallel imprint many individual NPs with high throughput and accuracy in a single step. Raman spectroscopy confirms enhanced light–matter interactions in the resulting NPoM-based nanophotonic devices. Our method mixes top-down and bottom-up nanofabrication techniques and shows the potential of building complex photonic nanodevices for multiple applications ranging from enhanced sensing and spectroscopy to signal processing