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Fractional optical angular momentum and multi-defect-mediated mode renormalization and orientation control in photonic crystal microring resonators
Published
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.
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 9, 2025)