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We experimentally and theoretically investigate in-medium propagation effects of off-resonant light in dense, spatially homogeneous ultacold atomic gases. Focussing on frequency modulation spectroscopy as the dispersive detection tool of…

Quantum Gases · Physics 2020-07-20 A. B. Deb , J. Chung , N. Kjærgaard

An optical antenna can convert a propagative optical radiation into a localized excitation, and reciprocally. Although optical antennas can be readily created using resonant nanoparticles (metallic or dielectric) as elementary building…

We present a novel antireflection approach utilizing planar metamaterials on dielectric surfaces. It consists of a split-ring resonator array and a metal mesh separated by a thin dielectric spacer. The coating dramatically reduces the…

Optics · Physics 2010-09-09 H. -T. Chen , J. Zhou , J. F. O'Hara , F. Chen , A. K. Azad , A. J. Taylor

Plasmonic wireless nanolinks hold great promise to overcome limitations from conventional metallic wires, namely narrow bandwidths, Ohmic losses, dispersion and cross-talking. However, current developments are limited to the wireless…

The manipulation of light by conventional optical components such as a lenses, prisms and wave plates involves engineering of the wavefront as it propagates through an optically-thick medium. A new class of ultra-flat optical components…

Polymer micro- and nano-fibers, made of organic light-emitting materials with optical gain, show interesting lasing properties. Fibers with diameters from few tens of nm to few microns can be fabricated by electrospinning, a method based on…

Materials Science · Physics 2013-12-02 Andrea Camposeo , Luana Persano , Dario Pisignano

Resolving fine details of astronomical objects provides critical insights into their underlying physical processes. This drives in part the desire to construct ever-larger telescopes and interferometer arrays and to observe at shorter…

In this paper we present the design of a flat-base Luneburg type of lens antenna, designed for wide angle scan. The antenna consists of a 11-layer lens, fed at its base by a 6x6 array of waveguides. The lens is broadband and has a high…

Optics · Physics 2013-05-07 Sidharath Jain , Raj Mittra

The spectral response of a plasmonic nanostructure may heavily depend on the refractive index of its surroundings. The key idea of this paper is to control this response by coherent optical means, i.e. with an optically controlled…

To extend the antenna design on printed circuit boards (PCBs) for more engineers of interest, we propose a simple method that models PCB antennas with a few basic components. By taking two separate steps to decide their geometric dimensions…

Computer Vision and Pattern Recognition · Computer Science 2024-01-15 Yang Zhong , Weiping Dou , Andrew Cohen , Dia'a Bisharat , Yuandong Tian , Jiang Zhu , Qing Huo Liu

Substituting noble metals for high-index dielectrics has recently been proposed as an alternative strategy in nanophotonics to design broadband optical resonators and circumvent the ohmic losses of plasmonic materials. In this report, we…

We investigate the fluorescence properties of colloidal quantum dots attached to gold rod nanoantennas. These structures are fabricated by a two step electron beam lithography process in combination with a chemical linking method. By…

The enhancement of the photoluminescence of quantum dots induced by an optical nanoantenna has been studied considerably, but there is still significant interest in optimizing and miniaturizing such structures, especially when accompanied…

Low cost methods of antenna production primarily aim to reduce the cost of metalization. This might lead to a reduction in conductivity. A systematic study on the impact of conductivity is presented. The efficiency, gain and bandwidth of…

General Physics · Physics 2016-04-27 Morteza Shahpari , David V. Thiel

We investigate the properties of finite gold nanocones as optical antennas for enhancing molecular fluorescence. We compute the modification of the excitation rate, spontaneous emission rate, and quantum efficiency as a function of the…

Chemical Physics · Physics 2010-05-04 Ahmad Mohammadi , Franziska Kaminski , Vahid Sandoghdar , Mario Agio

Dielectric microspheres or microbeads can squeeze light into the subwavelength scale via photonic nanojet (PNJ) focusing. This enables strong light-matter interactions within its focus and induces extraordinary effects such as enhancements…

Optics · Physics 2021-07-12 Pengcheng Zhang , Bing Yan , Guoqiang Gu , Zitong Yu , Xi Chen , Zengbo Wang , Hui Yang

The propagation of magnetostatic forward volume waves excited by a constricted coplanar waveguide is studied via inductive spectroscopy techniques. A series of devices consisting of pairs of sub-micrometer size antennae is used to perform a…

Mesoscale and Nanoscale Physics · Physics 2018-10-31 Nicolás Loayza , Matthias Benjamin Jungfleisch , Axel Hoffmann , Matthieu Bailleul , Vincent Vlaminck

High-frequency focused ultrasound is widely used in biomedical applications such as high-resolution imaging, neuromodulation, particle manipulation, and so on. However, dynamic tuning of the focal plane in conventional systems often relies…

Applied Physics · Physics 2026-04-15 Shiyu Li , Yicheng Feng , Weiwei Cui , Zhixiong Gong

Humankind has long endeavored to control the propagation direction of light. Since time immemorial, shades, lenses and mirrors have been used to control the flow of light. In modern society, with the rapid development of nanotechnology, the…

Recent progress in nanotechnology has enabled us to fabricate subwavelength architectures that function as antennas for improving the exchange of optical energy with nanoscale matter. We describe the main features of optical antennas for…

Optics · Physics 2012-02-02 Mario Agio