Dark-field spin Hall effect of light

Baishya, Upasana; Kumar, Nitish; Viswanathan, Nirmal K.

doi:10.1364/ol.468088

Cited by 9 publications

(2 citation statements)

References 39 publications

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“…This implies symmetry breaking and leads to the appearance of spin-Hall effect of light studied. 13,14 Together one can clearly see that a uniformly polarized Gaussian input beam is completely modified upon high-NA focusing, bringing to the other field components which were not present originally.…”

Section: Electric Field Distribution At the Focal Planementioning

confidence: 93%

Near complete spin-to-orbital angular momentum conversion in a focused-reflected beam of light

Viswanathan

Kumar

2023

Complex Light and Optical Forces XVII

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It is known for a while now that a focused circularly-polarized Gaussian beam produces vortex mode of topological charge ±1 in the longitudinal field component. While the remaining transverse field component in the focal region is paid little attention to, it is important to note that it is spatially inhomogeneous due to superposition of parallel and orthogonal to the input field components. Reflecting the focused light beam using a highly reflecting mirror, kept at the focal plane, followed by polarization filtering of the beam in the Fourier plane leads us to realize high-quality and high-conversion efficiency optical vortex beam of charge ±2, which depends on the input beam spin, σ = ±1. We present here the theoretical formulation to understand the generation of vortex beam followed by simulation and experimental demonstration to ascertain the anticipation.

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Section: Electric Field Distribution At the Focal Planementioning

confidence: 93%

Near complete spin-to-orbital angular momentum conversion in a focused-reflected beam of light

Viswanathan

Kumar

2023

Complex Light and Optical Forces XVII

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“…For the purpose of experimental observations, we build an optical system based on a normal incidence and reflection scheme [4,8,10,22,24,26,27], as shown in figure 12. A Gaussian He-Ne laser beam (λ = 632.8 nm) from the source L S is passed through a collimating lens pair L P .…”

Section: Methodsmentioning

confidence: 99%

Complex far fields and optical singularities due to propagation beyond tight focusing: combined effects of wavefront curvature and aperture diffraction

Kumar,

Debnath,

Viswanathan

2024

J. Opt.

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All optical systems, which involve the collimation of a reﬂected, transmitted or scattered wave subsequent to tight focusing, are subject to two kinds of deviations. One is the wavefront curvature due to inaccurate focal placement of the interface or scatterer particle under consideration, and the other is the diﬀraction caused by the ﬁnite lens aperture. In the present paper we explore these phenomena in detail by considering a rigorous simulated model and an appropriate experimental setup. We hence demonstrate the complicated intensity proﬁles and optical singularity characteristics of the observed far ﬁeld. Then we describe ways to minimize these deviations in a general experiment. But more importantly, our analysis proves that these deviations by themselves are signiﬁcant optical phenomena of fundamental interest. The observed complex ﬁeld proﬁles have similarities to standard diﬀraction-limited tight focal ﬁelds, though our ﬁeld detection is diﬀerent from the standard schemes. This indicates the relevance of these complex ﬁelds to a larger class of systems involving wavefront curvature and aperture diﬀraction. The detailed analysis and results of the present paper already serve as core explorations of these optical phenomena; and we also suggest future research directions where these system aspects can be purposefully created and explored further.

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On anomalous optical beam shifts at near-normal incidence

et al. 2022

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We develop the theory of optical beam shifts (both Goos–Hänchen and Imbert–Fedorov) for the case of near-normal incidence, when the incident angle becomes comparable with the angular beam divergence. The developed theory uncovers the unified origin of the anomalous beam shift enhancement via the geometric Berry phase singularity. Particularly, we predict the large Goos–Hänchen shift occurring for small incidence angles. We also propose a simple experimental scheme involving a quarter-wave q-plate that allows us to observe the giant transverse and longitudinal, spatial and angular beam shifts simultaneously. Finally, we analyze the relevant beam parameters, polarization structure, and intensity profiles of the shifted transmitted beam. Our results can find applications in spin–orbit photonics, polarization optics, sensing applications, and quantum weak measurements.

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Dark-field spin Hall effect of light

Cited by 9 publications

References 39 publications

Near complete spin-to-orbital angular momentum conversion in a focused-reflected beam of light

Near complete spin-to-orbital angular momentum conversion in a focused-reflected beam of light

Complex far fields and optical singularities due to propagation beyond tight focusing: combined effects of wavefront curvature and aperture diffraction

On anomalous optical beam shifts at near-normal incidence

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