792 research outputs found
Paraxial ray optics cloaking
Despite much interest and progress in optical spatial cloaking, a
three-dimensional (3D), transmitting, continuously multidirectional cloak in
the visible regime has not yet been demonstrated. Here we experimentally
demonstrate such a cloak using ray optics, albeit with some edge effects. Our
device requires no new materials, uses isotropic off-the-shelf optics, scales
easily to cloak arbitrarily large objects, and is as broadband as the choice of
optical material, all of which have been challenges for current cloaking
schemes. In addition, we provide a concise formalism that quantifies and
produces perfect optical cloaks in the small-angle (`paraxial') limit
Paraxial full-field cloaking
We complete the `paraxial' (small-angle) ray optics cloaking formalism
presented previously [Choi and Howell, Opt. Express 22, 29465 (2014)], by
extending it to the full-field of light. Omnidirectionality is then the only
relaxed parameter of what may be considered an ideal, broadband, field cloak.
We show that an isotropic plate of uniform thickness, with appropriately
designed refractive index and dispersion, can match the phase over the whole
visible spectrum. Our results support the fundamental limits on cloaking for
broadband vs. omnidirectionality, and provide insights into when anisotropy may
be required
Multicolour Entanglement
The entanglement of squeezed light beams is critical for quantum optical applications, but has so far been achieved with only two light beams. Now, researchers have surpassed this restriction and achieved entanglement with three beams of different colours. They also report a finite loss level for disentanglement of one beam from the other two
Paraxial Full-Field Cloaking
We complete the ‘paraxial’ (small-angle) ray optics cloaking formalism presented previously [Opt. Express 22, 29465 (2014)], by extending it to the full-field of light. Omnidirectionality is then the only relaxed parameter of what may be considered an ideal, broadband, field cloak. We show that an isotropic plate of uniform thickness, with appropriately designed refractive index and dispersion, can match the phase over the whole visible spectrum. Our results support the fundamental limits on cloaking for broadband vs. omnidirectionality, and provide insights into when anisotropy may be required
Paraxial Ray Optics Cloaking
Despite much interest and progress in optical spatial cloaking, a three-dimensional (3D), transmitting, continuously multidirectional cloak in the visible regime has not yet been demonstrated. Here we experimentally demonstrate such a cloak using ray optics, albeit with some edge effects. Our device requires no new materials, uses isotropic off-the-shelf optics, scales easily to cloak arbitrarily large objects, and is as broadband as the choice of optical material, all of which have been challenges for current cloaking schemes. In addition, we provide a concise formalism that quantifies and produces perfect optical cloaks in the small-angle (‘paraxial’) limit
Digital Integral Cloaking
Toward the goal of achieving broadband and omnidirectional invisibility, we propose a method for practical invisibility cloaking. We call this “digital cloaking,” where space, angle, spectrum, and phase are discretized. Experimentally, we demonstrate a two-dimensional (2D) planar, ray optics, digital cloak by using lenticular lenses, similar to “integral imaging” for three-dimensional (3D) displays. Theoretically, this can be extended to a good approximation of an “ideal” 3D cloak. With continuing improvements in commercial digital technology, the resolution limitations of a digital cloak can be minimized
Historical, Architectural, & Archeological Research at Brattonsville (38YK21), York County, South Carolina
https://scholarcommons.sc.edu/archanth_books/1070/thumbnail.jp
Shifting the Quantum-Classical Boundary: Theory and Experiment for Statistically Classical Optical Fields
The growing recognition that entanglement is not exclusively a quantum property, and does not even originate with Schrödinger’s famous remark about it [Proc. Cambridge Philos. Soc. 31, 555 (1935)], prompts the examination of its role in marking the quantum-classical boundary. We have done this by subjecting correlations of classical optical fields to new Bell-analysis experiments and report here values of the Bell parameter greater than ℬ=2.54. This is many standard deviations outside the limit ℬ=2 established by the Clauser–Horne–Shimony–Holt Bell inequality [Phys. Rev. Lett. 23, 880 (1969)], in agreement with our theoretical classical prediction, and not far from the Tsirelson limit ℬ=2.828…. These results cast a new light on the standard quantum-classical boundary description, and suggest a reinterpretation of it
HyFlex pedagogy: six strategies supported by design-based research
Purpose–This study investigates the following research question: What pedagogical strategies are necessary for the success of the project? The findings to this question are based in new media literacies and help to further pedagogy in an emerging HyFlex model while also grounding in needed theorization.
Design/methodology/approach–This study uses design-based research(DBR) across two iterations and four doctoral, higher education courses, using mixed methods of data collection and analysis.
Findings–Six pedagogical strategies influential for HyFlex research are presented, each grounded in a new media literacy skill.
Originality/value–These six pedagogical strategies help practitioners grappling with the HyFlex or blended learning model merge traditional pedagogy with how this might be tailored for students entrenched in a participatory culture
Double Lorentzian Atomic Prism
We present an atomic prism spectrometer that utilizes the steep linear dispersion between two strongly absorbing hyperfine resonances of rubidium. We resolve spectral lines 50 MHz apart and, utilizing a larger part of the available spectrum than only between the two resonances, we spatially separate collinear pump, signal, and idler beams resulting from a four-wave mixing process. Due to the high transparency possible between the resonances, these results have applications in the filtering of narrow-band entangled photons and interaction-free measurements
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