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Moumita Dutta, Soutik Betal, Xomalin G Peralta, Amar S Bhalla, Ruyan Guo
Phase modulators are one of the key components of many applications in electromagnetic and opto-electric wave propagations. Phase-shifters play an integral role in communications, imaging and in coherent material excitations. In order to realize the terahertz (THz) electromagnetic spectrum as a fully-functional bandwidth, the development of a family of efficient THz phase modulators is needed. Although there have been quite a few attempts to implement THz phase modulators based on quantum-well structures, liquid crystals, or meta-materials, significantly improved sensitivity and dynamic control for phase modulation, as we believe can be enabled by piezoelectric-resonance devices, is yet to be investigated...
November 30, 2016: Scientific Reports
Kaushik Subramanian, Ilan Gabay, Onur Ferhanoğlu, Adam Shadfan, Michal Pawlowski, Ye Wang, Tomasz Tkaczyk, Adela Ben-Yakar
We present the development of a 5 mm, piezo-actuated, ultrafast laser scalpel for fast tissue microsurgery. Delivery of micro-Joules level energies to the tissue was made possible by a large, 31 μm, air-cored inhibited-coupling Kagome fiber. We overcome the fiber's low NA by using lenses made of high refractive index ZnS, which produced an optimal focusing condition with 0.23 NA objective. The optical design achieved a focused laser spot size of 4.5 μm diameter covering a 75 × 75 μm(2) scan area in a miniaturized setting...
November 1, 2016: Biomedical Optics Express
Vinod Kumar Gupta, Ram Adhar Singh
Organic D-π-A materials, possessing intramolecular charge transfer, have attracted much scientific attention in recent years because of their potential applications in the development of organic light emitting devices (OLEDs). Two new compounds, A1 and A2, having a D-π-A skeleton have been synthesized and single crystals were grown by the solution growth technique. Both compounds were characterized for crystallographic, thermal and photophysical properties. Upon photo-excitation in the solid state, A1 showed very strong green light emission while A2 gave sky-blue emission with much lower intensity...
November 28, 2016: Faraday Discussions
Pau Farrera, Georg Heinze, Boris Albrecht, Melvyn Ho, Matías Chávez, Colin Teo, Nicolas Sangouard, Hugues de Riedmatten
The generation of ultra-narrowband, pure and storable single photons with widely tunable wave shape is an enabling step toward hybrid quantum networks requiring interconnection of remote disparate quantum systems. It allows interaction of quantum light with several material systems, including photonic quantum memories, single trapped ions and opto-mechanical systems. Previous approaches have offered a limited tuning range of the photon duration of at most one order of magnitude. Here we report on a heralded single photon source with controllable emission time based on a cold atomic ensemble, which can generate photons with temporal durations varying over three orders of magnitude up to 10 μs without a significant change of the readout efficiency...
November 25, 2016: Nature Communications
George Trichonas, Elias I Traboulsi, Justis P Ehlers
PURPOSE: Ultra-widefield fundus autofluorescence (UW-FAF) allows the characterization of the peripheral retinal features of vitreoretinal diseases. The purpose of this study was to examine possible genotypic/phenotypic correlations of UW-FAF patterns in patients with a variety of retinal dystrophies and retinitis pigmentosa (RP). METHODS: An IRB-approved retrospective consecutive case series study was performed of genetically characterized retinal dystrophy or RP patients who underwent UW-FAF imaging...
November 23, 2016: Ophthalmic Genetics
Ke Liu, Shuai Sun, Arka Majumdar, Volker J Sorger
The success of information technology has clearly demonstrated that miniaturization often leads to unprecedented performance, and unanticipated applications. This hypothesis of "smaller-is-better" has motivated optical engineers to build various nanophotonic devices, although an understanding leading to fundamental scaling behavior for this new class of devices is missing. Here we analyze scaling laws for optoelectronic devices operating at micro and nanometer length-scale. We show that optoelectronic device performance scales non-monotonically with device length due to the various device tradeoffs, and analyze how both optical and electrical constrains influence device power consumption and operating speed...
November 21, 2016: Scientific Reports
Ziya Isiksacan, Ozcan Erel, Caglar Elbuken
The erythrocyte sedimentation rate (ESR) is a frequently used 30 min or 60 min clinical test for screening of several inflammatory conditions, infections, trauma, and malignant diseases, as well as non-inflammatory conditions including prostate cancer and stroke. Erythrocyte aggregation (EA) is a physiological process where erythrocytes form face-to-face linear structures, called rouleaux, at stasis or low shear rates. In this work, we proposed a method for ESR measurement from EA. We developed a microfluidic opto-electro-mechanical system, using which we experimentally showed a significant correlation (R(2) = 0...
November 18, 2016: Lab on a Chip
Qingyu Meng, Hongyuan Wang, Kejun Wang, Yan Wang, Zhenhua Ji, Dong Wang
We report on the design of an off-axis three-mirror freeform telescope with a large field of view (FOV) based on an integration mirror (IM). This design is the continuation of the authors' previous work. Based on aberration theory, we established a suitable nonrelayed three-mirror-anastigmat initial configuration for integration mirror design. For an optical freeform surface, we analyzed the qualitative aberration correction ability of a x-y polynomial surface that can provide a simple, convenient, and user-friendly relationship between freeform surface term coefficients and aberrations and then applied the x-y polynomial surface on the tertiary mirror to improve the system optimization degrees of freedom...
November 10, 2016: Applied Optics
Jinjin Li, Yanhui Chu, Ka-Di Zhu
With the highly competitive development of communication technologies, modern information manufactures place high importance on the ability to control the transmitted signal using easy miniaturization materials. A controlled and miniaturized optical information device is, therefore, vital for researchers in information and communication fields. Here we propose a controlled signal transport in a doubly clamped carbon nanotube system, where the transmitted signal can be controlled by another pump beam. Pump off results in the transmitted signal off, while pump on results in the transmitted signal on...
November 16, 2016: Scientific Reports
Yoon Ho Huh, In-Gon Bae, Hong Goo Jeon, Byoungchoo Park
We herein report a homogeneous [6,6]-phenyl C<sub>61</sub> butyric acid methyl ester (PCBM) layer, produced by a solution process of horizontal-dipping (H-dipping) to improve the photovoltaic (PV) effects of bilayer heterojunction organic photovoltaic cells (OPVs) based on a bi-stacked poly(3-hexylthiophene) (P3HT) electron donor layer and a PCBM electron acceptor layer (P3HT/PCBM). It was shown that a homogeneous and uniform coating of PCBM layers in the P3HT/PCBM bilayer OPVs resulted in reliable and reproducible device performance...
October 31, 2016: Optics Express
M J A Smith, C Wolff, C M de Sterke, M Lapine, B T Kuhlmey, C G Poulton
Silicon is an ideal material for on-chip applications, however its poor acoustic properties limit its performance for important optoacoustic applications, particularly for stimulated Brillouin scattering (SBS). We theoretically show that silicon inverse opals exhibit a strongly improved acoustic performance that enhances the bulk SBS gain coefficient by more than two orders of magnitude. We also design a waveguide that incorporates silicon inverse opals and which has SBS gain values that are comparable with chalcogenide glass waveguides...
October 31, 2016: Optics Express
Ko-Ting Cheng, Yi Tang, Cheng-Kai Liu
This paper reports an electro-opto-thermal addressing bistable and re-addressable display device based on gelator-doped liquid crystals (LCs) in a poly(N-vinylcarbazole) film-coated LC cell. The bistability and re-addressability of the devices were achieved through the formation of a rubbery LC/gel mixture at room temperature. The desired patterns were addressed, erased, and re-addressed by controlling the temperature, applied voltage, and UV light illumination. Moreover, grayscales were obtained by adjusting UV light intensity...
October 3, 2016: Optics Express
Cejo Konuparamban Lonappan, Asad M Madni, Bahram Jalali
A new instrument for fast measurement of frequency response of high-bandwidth optical and electronic devices is reported. Single-shot frequency spectrum measurements are enabled by time-stretch technology. An extremely fast measurement time of 27 ns is reported for the instrument. The reported instrument enables single-shot impulse response measurements with a 40 GHz bandwidth, which could be extended to beyond 100 GHz by using a faster electro-optic modulator. An ultra-low jitter of 20.5 fs is reported for the proposed instrument...
October 20, 2016: Applied Optics
Alberto Privitera, Marcello Righetto, Dario Mosconi, Francesca Lorandi, Abdirisak A Isse, Alessandro Moretto, Renato Bozio, Camilla Ferrante, Lorenzo Franco
The design of novel nanostructures with tailored opto-electronic properties is a crucial step for third-generation photovoltaics, and the development of cheap and environmentally compatible materials is still a challenge. Carbon quantum dots (CQDs) emerged as promising candidates but usually a low processability and poor electron-donor properties hampered their photovoltaic applications. We tackle these issues through the synthesis and photophysical characterization of N-doped CQDs functionalized with different thiophene-containing groups...
November 16, 2016: Physical Chemistry Chemical Physics: PCCP
A LoMauro, A Aliverti, C Mastella, M T Arnoldi, P Banfi, G Baranello
INTRODUCTION: SMA is characterised by progressive motor and respiratory muscle weakness. We aimed to verify if in SMA children 1)each form is characterized by specific ventilatory and thoraco-abdominal pattern(VTAp) during quiet breathing(QB); 2)VTAp is affected by salbutamol therapy, currently suggested as standard treatment, or by the natural history(NH) of SMA; 3)the severity of global motor impairment linearly correlates with VTAp. MATERIALS AND METHODS: VTAp was analysed on 32 SMA type I (SMA1,the most severe form), 51 type II (SMA2,the moderate), 8 type III (SMA3,the mildest) and 20 healthy (HC) using opto-electronic plethysmography...
2016: PloS One
Iñigo Liberal, Nader Engheta
Controlling the emission and interaction properties of quantum emitters (QEs) embedded within an optical cavity is a key technique in engineering light-matter interactions at the nanoscale, as well as in the development of quantum information processing. State-of-the-art optical cavities are based on high quality factor photonic crystals and dielectric resonators. However, wealthier responses might be attainable with cavities carved in more exotic materials. We theoretically investigate the emission and interaction properties of QEs embedded in open epsilon-near-zero (ENZ) cavities...
October 2016: Science Advances
Yani Chen, Minhong He, Jiajun Peng, Yong Sun, Ziqi Liang
Recently, organic-inorganic halide perovskites have sparked tremendous research interest because of their ground-breaking photovoltaic performance. The crystallization process and crystal shape of perovskites have striking impacts on their optoelectronic properties. Polycrystalline films and single crystals are two main forms of perovskites. Currently, perovskite thin films have been under intensive investigation while studies of perovskite single crystals are just in their infancy. This review article is concentrated upon the control of perovskite structures and growth, which are intimately correlated for improvements of not only solar cells but also light-emitting diodes, lasers, and photodetectors...
April 2016: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Josien C van den Noort, Henk G Kortier, Nathalie van Beek, DirkJan H E J Veeger, Peter H Veltink
Objective analysis of hand and finger kinematics is important to increase understanding of hand function and to quantify motor symptoms for clinical diagnosis. The aim of this paper is to compare a new 3D measurement system containing multiple miniature inertial sensors (PowerGlove) with an opto-electronic marker system during specific finger tasks in three healthy subjects. Various finger movements tasks were performed: flexion, fast flexion, tapping, hand open/closing, ab/adduction and circular pointing. 3D joint angles of the index finger joints and position of the thumb and index were compared between systems...
2016: PloS One
A Della Pia, M Riello, D Stassen, T S Jones, D Bonifazi, A De Vita, G Costantini
Organic charge transfer (CT) complexes obtained by combining molecular electron donors and acceptors have attracted much interest due to their potential applications in organic opto-electronic devices. In order to work, these systems must have an electronic matching - the highest occupied molecular orbital (HOMO) of the donor must couple with the lowest unoccupied molecular orbital (LUMO) of the acceptor - and a structural matching, so as to allow direct intermolecular CT. Here it is shown that, when molecules are adsorbed on a metal surface, novel molecular organizations driven by surface-mediated CT can appear that have no counterpart in condensed phase non-covalent assemblies of donor and acceptor molecules...
December 7, 2016: Nanoscale
L Wang, R Cheaito, J L Braun, A Giri, P E Hopkins
The thermoreflectance-based techniques time- and frequency-domain thermoreflectance (TDTR and FDTR, respectively) have emerged as robust platforms to measure the thermophysical properties of a wide array of systems on varying length scales. Routine in the implementation of these techniques is the application of a thin metal film on the surface of the sample of interest to serve as an opto-thermal transducer ensuring the measured modulated reflectivity is dominated by the change in thermoreflectance of the sample...
September 2016: Review of Scientific Instruments
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