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Search Results: 1 - 10 of 426555 matches for " Thomas M. Babinec "
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Inverse design and demonstration of a compact and broadband on-chip wavelength demultiplexer
Alexander Y. Piggott,Jesse Lu,Konstantinos G. Lagoudakis,Jan Petykiewicz,Thomas M. Babinec,Jelena Vu?kovi?
Physics , 2015, DOI: 10.1038/nphoton.2015.69
Abstract: Integrated photonic devices are poised to play a key role in a wide variety of applications, ranging from optical interconnects and sensors to quantum computing. However, only a small library of semi-analytically designed devices are currently known. In this paper, we demonstrate the use of an inverse design method that explores the full design space of fabricable devices and allows us to design devices with previously unattainable functionality, higher performance and robustness, and smaller footprints compared to conventional devices. We designed a silicon wavelength demultiplexer that splits $1300~\mathrm{nm}$ and $1550~\mathrm{nm}$ light from an input waveguide into two output waveguides, and fabricated and characterized several devices. The devices display low insertion loss $\left(2 - 4~\mathrm{dB}\right)$, high contrast $\left(12 - 17~\mathrm{dB}\right)$, and wide bandwidths $\left(\sim 100~\mathrm{nm} \right)$. The device footprint is $2.8 \times 2.8 ~\mathrm{\mu m}$, making this the smallest dielectric wavelength splitter to date.
Inverse design and implementation of a wavelength demultiplexing grating coupler
Alexander Y. Piggott,Jesse Lu,Thomas M. Babinec,Konstantinos G. Lagoudakis,Jan Petykiewicz,Jelena Vu?kovi?
Physics , 2014, DOI: 10.1038/srep07210
Abstract: Nanophotonics has emerged as a powerful tool for manipulating light on chips. Almost all of today's devices, however, have been designed using slow and ineffective brute-force search methods, leading in many cases to limited device performance. In this article, we provide a complete demonstration of our recently proposed inverse design technique, wherein the user specifies design constraints in the form of target fields rather than a dielectric constant profile, and in particular we use this method to demonstrate a new demultiplexing grating. The novel grating, which has not been developed using conventional techniques, accepts a vertical-incident Gaussian beam from a free-space and separates O-band $(1300\mathrm{nm})$ and C-band $(1550\mathrm{nm})$ light into separate waveguides. This inverse design concept is simple and extendable to a broad class of highly compact devices including frequency splitters, mode converters, and spatial mode multiplexers.
Photonic Crystal Cavities in Cubic (3C) Polytype Silicon Carbide Films
Marina Radulaski,Thomas M. Babinec,Sonia Buckley,Armand Rundquist,J Provine,Kassem Alassaad,Gabriel Ferro,Jelena Vu?kovi?
Physics , 2013, DOI: 10.1364/OE.21.032623
Abstract: We present the design, fabrication, and characterization of high quality factor and small mode volume planar photonic crystal cavities from cubic (3C) thin films (thickness ~ 200 nm) of silicon carbide (SiC) grown epitaxially on a silicon substrate. We demonstrate cavity resonances across the telecommunications band, with wavelengths from 1,250 - 1,600 nm. Finally, we discuss possible applications in nonlinear optics, optical interconnects, and quantum information science.
A Light-Matter Interface based on a Single InAs/GaAs Quantum Dot in a Nanometallic Cavity
Yousif A. Kelaita,Kevin A. Fischer,Thomas M. Babinec,Konstantinos G. Lagoudakis,Tomas Sarmiento,Armand Rundquist,Arka Majumdar,Jelena Vuckovic
Physics , 2014,
Abstract: Despite tremendous advances in the fundamentals and applications of cavity quantum electrodynamics with single InAs/GaAs quantum dots, investigations in this field have been limited to optical cavities composed of purely dielectric materials. Here, we demonstrate for the first time the coupling of an InAs/GaAs quantum dot to a hybrid metal/semiconductor nanocavity consisting of a GaAs nanocylinder embedded in a metallic film. Key features of our nanometallic light-matter interface include: (i) order of magnitude reduction in mode volume compared to that of leading photonic crystal CQED systems, resulting in a maximum atom-field coupling rate of g/(2{\pi}) ~180 GHz for InAs/GaAs quantum dots; (ii) surface-emitting nanocylinder geometry and therefore good collection efficiency compared to the bulk (~5X enhancement); and finally (iii) strong and broadband spontaneous emission rate enhancement (Purcell factor ~8). This light-matter interface may play an important role in the fundamentals of cavity quantum electrodynamics as well as in its application to optical interconnects and quantum networks.
Single Color Centers Implanted in Diamond Nanostructures
Birgit J. M. Hausmann,Thomas M. Babinec,Jennifer T. Choy,Jonathan S. Hodges,Sungkun Hong,Irfan Bulu,A. Yacoby,M. D. Lukin,Marko Lon?ar
Physics , 2010, DOI: 10.1088/1367-2630/13/4/045004
Abstract: The development of materials processing techniques for optical diamond nanostructures containing a single color center is an important problem in quantum science and technology. In this work, we present the combination of ion implantation and top-down diamond nanofabrication in two scenarios: diamond nanopillars and diamond nanowires. The first device consists of a 'shallow' implant (~20nm) to generate Nitrogen-vacancy (NV) color centers near the top surface of the diamond crystal. Individual NV centers are then isolated mechanically by dry etching a regular array of nanopillars in the diamond surface. Photon anti-bunching measurements indicate that a high yield (>10%) of the devices contain a single NV center. The second device demonstrates 'deep' (~1\mu m) implantation of individual NV centers into pre-fabricated diamond nanowire. The high single photon flux of the nanowire geometry, combined with the low background fluorescence of the ultrapure diamond, allows us to sustain strong photon anti-bunching even at high pump powers.
Visible Photoluminescence from Cubic (3C) Silicon Carbide Microdisks Coupled to High Quality Whispering Gallery Modes
Marina Radulaski,Thomas M. Babinec,Kai Müller,Konstantinos G. Lagoudakis,Jingyuan Linda Zhang,Sonia Buckley,Yousif A. Kelaita,Kassem Alassaad,Gabriel Ferro,Jelena Vu?kovi?
Physics , 2014, DOI: 10.1021/ph500384p
Abstract: We present the design, fabrication and characterization of cubic (3C) silicon carbide microdisk resonators with high quality factor modes at visible and near infrared wavelengths (600 - 950 nm). Whispering gallery modes with quality factors as high as 2,300 and corresponding mode volumes V ~ 2 ({\lambda}/n)^3 are measured using laser scanning confocal microscopy at room temperature. We obtain excellent correspondence between transverse-magnetic (TM) and transverse-electric (TE) polarized resonances simulated using Finite Difference Time Domain (FDTD) method and those observed in experiment. These structures based on ensembles of optically active impurities in 3C-SiC resonators could play an important role in diverse applications of nonlinear and quantum photonics, including low power optical switching and quantum memories.
Readout and control of a single nuclear spin with a meta-stable electron spin ancilla
Sang-Yun Lee,Matthias Widmann,Torsten Rendler,Marcus Doherty,Thomas M. Babinec,Sen Yang,Moritz Eyer,Petr Siyushev,Birgit J. M. Haussmann,Marko Loncar,Zoltán Bodrog,Adam Gali,Neil Manson,Helmut Fedder,J?rg Wrachtrup
Physics , 2013, DOI: 10.1038/nnano.2013.104
Abstract: Electron and nuclear spins associated with point defects in insulators are promising systems for solid state quantum technology. While the electron spin usually is used for readout and addressing, nuclear spins are exquisite quantum bits and memory systems. With these systems single-shot readout of nearby nuclear spins as well as entanglement aided by the electron spin has been shown. While the electron spin in this example is essential for readout it usually limits nuclear spin coherence. This has set of the quest for defects with spin-free ground states. Here, we isolate a hitherto unidentified defect in diamond and use it at room temperature to demonstrate optical spin polarization and readout with exceptionally high contrast (up to 45%), coherent manipulation of an individual excited triplet state spin, and coherent nuclear spin manipulation using the triplet electron spin as a meta-stable ancilla. By this we demonstrate nuclear magnetic resonance and Rabi oscillations of the uncoupled nuclear spin in the spin-free electronic ground state. Our study demonstrates that nuclei coupled to single metastable electron spins are useful quantum systems with long memory times despite electronic relaxation processes.
Feasibility of subcutaneously implanted magnetic microarrays for site specific drug and gene targeting
A. Kraf?ík,P. Babinec,M. Babincová
Journal of Engineering Science and Technology Review , 2010,
Abstract: The magnetic nanoparticles play a crucial role as a drug carriers in the human body. The wedge like magnetic arrays creatinga strongly non-homogeneous magnetic field are considered as a useful way to focus magnetic nanoparticles functionalizedwith various drugs or genes to desired sites. The goal of this study is to develop a numerical model of drug targetingusing subcutaneously implanted magnetic microarrays. The Finite Element Method is applied to solve partial differentialequations describing electromagnetic field (Maxwell equations) and motion of these particles in a given magnetic field isobtained solving set of ordinary differential equations expressed by Newton law of motion. The results are encouragingshowing the potential to target drug to the tumour cell locally, without unwanted side effects.
Magnetoliposome Mediated Local Electromagnetic Tumor Hyperthermia
M. Babincova,P. Cicmanec,P. Babinec,V. Altanerova
Radioengineering , 2000,
Abstract: Magnetoliposomes prepared by enwrapping 8 nm sized superparamagnetic magnetite grains with phospholipid bilayer were evaluated as possible new material for local electromagnetic hyperthermia both in vitro and in vivo after their injection into implanted BP-6 tumor in rats. As has been found the center of tumor is heated in 10 minutes from 35 °C to 44.1 °C using magnetic field with induction 1.5 mT and frequency 3.5 MHz.
Hybrid Group IV Nanophotonic Structures Incorporating Diamond Silicon-Vacancy Color Centers
Jingyuan Linda Zhang,Hitoshi Ishiwata,Thomas M. Babinec,Marina Radulaski,Kai Müller,Konstantinos G. Lagoudakis,Constantin Dory,Jeremy Dahl,Robert Edgington,Veronique Soulière,Gabriel Ferro,Andrey A. Fokin,Peter R. Schreiner,Zhi-Xun Shen,Nicholas A. Melosh,Jelena Vu?kovi?
Physics , 2015,
Abstract: We demonstrate a new approach for engineering group IV semiconductor-based quantum photonic structures containing negatively charged silicon-vacancy (SiV$^-$) color centers in diamond as quantum emitters. Hybrid SiC/diamond structures are realized by combining the growth of nanoand micro-diamonds on silicon carbide (3C or 4H polytype) substrates, with the subsequent use of these diamond crystals as a hard mask for pattern transfer. SiV$^-$ color centers are incorporated in diamond during its synthesis from molecular diamond seeds (diamondoids), with no need for ionimplantation or annealing. We show that the same growth technique can be used to grow a diamond layer controllably doped with SiV$^-$ on top of a high purity bulk diamond, in which we subsequently fabricate nanopillar arrays containing high quality SiV$^-$ centers. Scanning confocal photoluminescence measurements reveal optically active SiV$^-$ lines both at room temperature and low temperature (5 K) from all fabricated structures, and, in particular, very narrow linewidths and small inhomogeneous broadening of SiV$^-$ lines from all-diamond nano-pillar arrays, which is a critical requirement for quantum computation. At low temperatures (5 K) we observe in these structures the signature typical of SiV$^-$ centers in bulk diamond, consistent with a double lambda. These results indicate that high quality color centers can be incorporated into nanophotonic structures synthetically with properties equivalent to those in bulk diamond, thereby opening opportunities for applications in classical and quantum information processing.
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