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Journal ArticleDOI

Optical mode-coupling in a ring due to a back-scatterer

01 Feb 1993-Pramana (Springer India)-Vol. 40, Iss: 2, pp 107-112
TL;DR: In this article, the coupling of light waves travelling clockwise and counterclockwise along an optical ring due to a backscattering element is studied, and an asymmetric mode splitting occurs as a consequence of the discontinuity suffered by the waves at the scattering point.
Abstract: The coupling of light waves travelling clockwise and counterclockwise along an optical ring due to a back-scattering element is studied. An asymmetric mode splitting occurs as a consequence of the discontinuity suffered by the waves at the scattering point. The mode splitting shows up in an interference pattern and lends itself to an experimental verification.
Citations
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Journal ArticleDOI
TL;DR: These experiments present experiments where a single subwavelength scatterer is used to examine and control the backscattering induced coupling between counterpropagating high-Q modes of a microsphere resonator, and reveal the standing wave character of the resulting symmetric and antisymmetric eigenmodes.
Abstract: We present experiments where a single subwavelength scatterer is used to examine and control the backscattering induced coupling between counterpropagating high-Q modes of a microsphere resonator. Our measurements reveal the standing wave character of the resulting symmetric and antisymmetric eigenmodes, their unbalanced intensity distributions, and the coherent nature of their coupling. We discuss our findings and the underlying classical physics in the framework common to quantum optics and provide a particularly intuitive explanation of the central processes.

288 citations

Journal ArticleDOI
TL;DR: In this article, a survey and analysis of recent work on topological phases with polarization of light is presented, which has revealed several counterintuitive features of such phase shifts such as 2 nπ anholonomies, nonlinear and discontinuous behaviour originating from high singularities, peculiar spectral dependence, etc.

256 citations

Journal ArticleDOI
TL;DR: In this paper, a system of two eccentric spheres, wherein an inclusion sphere is embedded in a larger sphere with a different refractive index, is considered, and the authors demonstrate broken azimuthal degeneracy for non-axisymmetric illumination resulting in splittings in extinction peaks.
Abstract: We consider a system of two eccentric spheres, wherein an inclusion sphere is embedded in a larger sphere with a different refractive index. We demonstrate broken azimuthal degeneracy for non-axisymmetric illumination resulting in splittings in extinction peaks. The mode splitting and mixing effects are shown to be nonresonant, valid for all modes having sufficient quality factors. We demonstrate strong dependence of the splittings on the polarization of the incident light to the extent that one can diagnose the polarization characteristics of the whispering gallery mode. We show how a set of quantum numbers can be assigned to a given peak of the split resonances. We further investigate the field distribution in suitable coordinate planes in order to bring out the close relation between the magnetic quantum number, the polarization of the bisphere modes and that of incident light.

13 citations

Journal ArticleDOI
TL;DR: In this paper , the authors proposed a coupled mode theory with the required time reversal symmetry properties which influences the Berry curvature and showed that it leads to the accumulation of Berry phase with tunable topological charge.
Abstract: A Sagnac interferometer’s ring structure causes electromagnetic waves traversing it to periodically encounter the same optical elements. Due to this discrete translational symmetry, the frequency spectrum of the clockwise and counter-clockwise modes acquire a band structure with a characteristic band gap. When the interferometer is rotated, an additional non-reciprocal phase shift between the counter propagating modes arises and it results in the loss of time reversal symmetry. While prior understanding of the impact of Sagnac rotation on the band structure exists, the prevalence of topological geometric phase in Sagnac interferometer under rotation has not been prominently discussed. We propose a coupled mode theory with the required time reversal symmetry properties which influences the Berry curvature and we show that it leads to the accumulation of Berry phase with tunable topological charge.
References
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TL;DR: In this paper, the authors investigated backscattering effects in a He-Ne ring laser and confirmed the prediction based on third-order laser theory that equal-time moments depend on backscatter only through the combination R1 + R2*, where R1 and R2 are complex backscasting coefficients.
Abstract: By making provisions for retroreflecting the two emerging counterrotating waves back into the laser cavity with variable amplitudes and phases, we have investigated backscattering effects in a He–Ne ring laser. In particular, we have measured the intensity flucuations and the intensity cross correlation between the two counterpropagating modes as the pump parameter and the phase of the backscattering are varied. We confirm the prediction based on third-order laser theory that equal-time moments depend on backscattering only through the combination R1 + R2*, where R1 and R2 are complex backscattering coefficients. Good agreement between experiment and third-order laser theory is obtained so long as the normalized pump parameter is below approximately 100.

11 citations