Locally-outcoupled cavity resonator having unidirectional emission
AssigneeXerox Corporation
InventorsMichael A. Kneissl, Noble M. Johnson, David K. Biegelsen, Richard K. Chang, A. Douglas Stone, Grace D. Chern, Hakan E. Tureci, Joseph Zyss
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Abstract
A locally-outcoupled optical resonator has whispering gallery modes existing in a nearly circular resonator. Light is outcoupled by providing a local perturbing feature on the perimeter of the locally-outcoupled cavity resonator. The perturbing feature provides an outcoupling or loss mechanism that asymmetrically interacts with circulating whispering gallery modes, thereby making the resonator capable of uni-directional output.
Claims48
A locally-outcoupled optical resonator, having a substantially smooth curved outer periphery bounded by reflective walls, in which light can circulate in at least a pair of possible directions, the curved outer periphery including at least one local perturbing feature, the perturbing feature serving to asymmetrically outcouple light circulating in a first one of the pair of possible directions within the curved outer periphery, into propagating free space modes, and the perturbing feature is an indentation in the substantially smooth curved outer periphery.
A locally-outcoupled optical resonator, having a substantially smooth curved outer periphery bounded by reflective walls, in which light can circulate in at least a pair of possible directions, the curved outer periphery including at least one local perturbing feature, the perturbing feature serving to asymmetrically outcouple light circulating in a first one of the pair of possible directions within the curved outer periphery, into propagating free space modes, wherein the perturbing feature is a protrusion extending outward from the smooth curved outer periphery, the protrusion provides an optical path to outcouple light circulating in the first of the pair of directions within the locally-outcoupled optical resonator, the protrusion has a reflective surface, and the reflective surface reflects light incident from a second one of the pair of possible directions, into the first one of the pair of possible directions.
A locally-outcoupled optical resonator, having a substantially smooth curved outer periphery bounded by reflective walls, in which light can circulate in at least a pair of possible directions, the curved outer periphery including at least one local perturbing feature, the perturbing feature serving to asymmetrically outcouple light circulating in a first one of the pair of possible directions within the curved outer periphery, into propagating free space modes, wherein:
- the substantially smooth outer periphery is a spiral shape of continuously varying radius defined by the relationship:
- rθ=r0(1+∈θ/2π)
- where:
- r0 is a minimum radius,
- ∈ is a spiral deformation parameter, and
- θ is a rotation angle about a spiral center;
- and
- the perturbing feature is an output aperture resulting from a discontinuity in the spiral shape, at which the outer radius of the spiral changes from a value of rθ=r0 at θ=0 to rθ=r0(1+∈) at θ=/2π.
A locally-outcoupled optical resonator, having a substantially smooth curved outer periphery bounded by reflective walls, in which light can circulate in at least a pair of possible directions, the curved outer periphery including at least one local perturbing feature, the perturbing feature serving to asymmetrically outcouple light circulating in a first one of the pair of possible directions within the curved outer periphery, into propagating free space modes, wherein the smooth curved outer periphery comprises two semicircular portions each having smooth outer edges, and the two semicircular portions are positioned so that the at least one perturbing feature is at least one output aperture formed by at least one discontinuity between the outer edges of the two semicircular portions.
A locally-outcoupled optical resonator, having a substantially smooth curved outer periphery bounded by reflective walls, in which light can circulate in at least a pair of possible directions, the curved outer periphery including at least one local perturbing feature, the perturbing feature serving to asymmetrically outcouple light circulating in a first one of the pair of possible directions within the curved outer periphery, into propagating free space modes, wherein the smooth curved outer periphery comprises two semicircular portions each having smooth outer edges, and the two semicircular portions have two different radii.
Dependencies are inferred from the claim text.