Fractional optical angular momentum and multi-defect-mediated mode renormalization and orientation control in photonic crystal microring resonators

Published

October 28, 2022

Author(s)

Mingkang Wang, Feng Zhou, Xiyuan Lu, Andrew McClung, Vladimir Aksyuk, Kartik Srinivasan

Abstract

Whispering gallery modes (WGMs) in circularly symmetric optical microresonators exhibit integer quantized angular momentum numbers due to the boundary condition imposed by the geometry. Here, we show that incorporating a photonic crystal pattern in an integrated microring can result in WGMs with fractional optical angular momentum. By choosing the photonic crystal periodicity to open a photonic bandgap with a bandedge momentum lying between that of two WGMs of the unperturbed ring, we observe hybridized WGMs with half-integer quantized angular momentum numbers (m = Z + 1/2). Moreover, we show that these modes with fractional angular momenta exhibit high optical quality factors with good cavity-waveguide coupling, and also can co-exist with more localized states when a defect is introduced in the photonic crystal lattice. Our work unveils WGMs with fractional angular momentum, which can be used in sensing/metrology, nonlinear optics, and cavity quantum electrodynamics.

Citation

Physical Review Letters

Volume

129

Pub Type

Journals

Download Paper

https://doi.org/10.1103/PhysRevLett.129.186101

Local Download

Keywords

Photonic crystal, angular momentum, slow light, mode localization

Citation

Wang, M. , Zhou, F. , Lu, X. , McClung, A. , Aksyuk, V. and Srinivasan, K. (2022), Fractional optical angular momentum and multi-defect-mediated mode renormalization and orientation control in photonic crystal microring resonators, Physical Review Letters, [online], https://doi.org/10.1103/PhysRevLett.129.186101 , https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934007 (Accessed October 20, 2025)