Resolving Light Handedness with an on-Chip Silicon Microdisk

Abstract

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.

Unidirectional evanescent-wave coupling from circularly polarized electric and magnetic dipoles: An angular spectrum approach

“…SOI effects are generally believed to be small unless enhanced with artificial materials [20,21]. However, in the present case, illuminated particles scatter light into completely opposite directions, constituting a remarkably simple yet drastic example of SOI, providing a unique opportunity for robust, integrated, ultrafast light nanorouting based on polarization [15,[22][23][24][25]. The effect can also have important consequences in the optical manipulation of chiral [26,27] and nonchiral nanoparticles [28][29][30][31], giving rise to unintuitive lateral forces, as well as applications in optical isolation [13,32].…”

Chiral quantum optics

“…The associated directional coupling has been observed experimentally in both dielectric [21][22][23][24][25][26][27][28][29][30][31] and plasmonic nanostructures [32][33][34][35] by coupling both classical [24-26, 30, 32-35] and quantum [21-23, 27-29, 31] emitters to the confined light fields. The robustness of the chiral points against unavoidable fabrication imperfections in photonic-crystal waveguides has been assessed [31,36] and chiral coupling is a well characterized and robust phenomenon, which is readily implementable in a range of applications.…”

“…5 a for a photonic-crystal waveguide. Directional emission has been observed experimentally with a range of different types of emitters embedded in various photonic nanostructures [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35].…”

Magnetic and Electric Transverse Spin Density of Spatially Confined Light

“…This notion is essential, for instance, in spin-momentum locking experiments based on silicon nanophotonics [21,34], where both electric and magnetic dipolar modes are supported [35][36][37] …”