1,609 research outputs found
Tunable acoustic gratings in solid-core photonic bandgap fiber
No full textWe investigate acousto-optic long period grating resonances in a fluid-filled solid-core photonic bandgap fiber (PBGF). The acoustic grating design enables electrically tunable notches in each of the PBGF transmission bands, where both the center frequency and depth of the resonances can be varied. The measured intermodal beat length and resonance bandwidth are in good agreement with numerical simulations based on multipole method. We show that the highly dispersive nature of PBGF modes results in very narrow-band rejection for a given grating pitch. (c) 2007 Optical Society of America.This work was produced with the assistance of the Australian Research Council under the
ARC Centres of Excellence program and supported by the Korea Research Foundation Grant
funded by the Korean Government (MOEHRD, Basic Research Promotion Fund) (KRF-2006-
214-C00029
Integrated sources of photon quantum states based on nonlinear optics
No full textThe ability to generate complex optical photon states involving entanglement between multiple optical modes is not only critical to advancing our understanding of quantum mechanics but will play a key role in generating many applications in quantum technologies. These include quantum communications, computation, imaging, microscopy and many other novel technologies that are constantly being proposed. However, approaches to generating parallel multiple, customisable bi- and multi-entangled quantum bits (qubits) on a chip are still in the early stages of development. Here, we review recent advances in the realisation of integrated sources of photonic quantum states, focusing on approaches based on nonlinear optics that are compatible with contemporary optical fibre telecommunications and quantum memory platforms as well as with chip-scale semiconductor technology. These new and exciting platforms hold the promise of compact, low-cost, scalable and practical implementations of sources for the generation and manipulation of complex quantum optical states on a chip, which will play a major role in bringing quantum technologies out of the laboratory and into the real world
Photosensitive post tuning of chalcogenide photonic crystal waveguides
No full textThis paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=oe-15-3-1277. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.We present experimental results on post-tuning the dispersion of a two-dimensional photonic crystal waveguide made from Ge(33)As(12)Se(55) chalcogenide glass by exploiting the material photosensitivity to near-bandgap light. The change in the refractive index and volume of the material in response to exposure to 633nm light resulted in a shift of more than 5nm in the resonant coupling wavelength between a tapered optical fiber and the modes of a W1 waveguide. This represents a first proof of principle demonstration of the photosensitive post-tuning of a planar photonic crystal device.Michael W. Lee, Christian Grillet, Cameron L. C. Smith, David J. Moss, Benjamin J. Eggleton, Darren Freeman, Barry Luther-Davies, Steve Madden, Andrei Rode, Yinlan Ruan, and Yong-hee Le
Experimental investigation of a nanofluid absorber employed in a low-profile, concentrated solar thermal collector
No full textRecent studies [1-3] have demonstrated that nanotechnology, in the form of nanoparticles suspended in water and organic liquids, can be employed to enhance solar collection via direct volumetric absorbers. However, current nanofluid solar collector experimental studies are either relevant to low-temperature flat plate solar collectors (100 °C) indoor laboratory-scale concentrating solar collectors [1, 5]. Moreover, many of these studies involve in thermal properties of nanofluid (such as thermal conductivity) enhancement in solar collectors by using conventional selective coated steel/copper tube receivers [6], and no full-scale concentrating collector has been tested at outdoor condition by employing nanofluid absorber [2, 6]. Thus, there is a need of experimental researches to evaluate the exact performance of full-scale concentrating solar collector by employing nanofluids absorber at outdoor condition. As reported previously [7-9], a low profile (<10 cm height) solar thermal concentrating collector was designed and analysed which can potentially supply thermal energy in the 100-250 °C range (an application currently met by gas and electricity). The present study focuses on the design and experimental investigation of a nanofluid absorber employed in this newly designed collector. The nanofluid absorber consists of glass tubes used to contain chemically functionalized multi-walled carbon nanotubes (MWCNTs) dispersed in DI water. MWCNTs (average diameter of 6-13 nm and average length of 2.5-20 μm) were functionalized by potassium persulfate as an oxidant. The nanofluids were prepared with a MCWNT concentration of 50 ± 0.1 mg/L to form a balance between solar absorption depth and viscosity (e.g. pumping power). Moreover, experimentally comparison of the thermal efficiency between two receivers (a black chrome-coated copper tube versus a MWCNT nanofluid contained within a glass tubetube) is investigated. Thermal experimentation reveals that while the collector efficiency reduced from 73% to 54% when operating temperature increased from ambient to 80 °C by employing a MWCNT nanofluid receiver, the efficiency decreased from 85% to 68% with same operating temperature range by employing black chrome-coated copper tube receiver. This difference can mainly be explained by the reflection optical loss off and higher thermal emission heat loss the front surface of the glass tube, yielding a 90% of transmittance to the MWCNT fluid and a 0.9 emissivity of glass pipe. Overall, an experimental investigation of the performance of a low profile solar collector with a direct volumetric absorber and conventional surface absorber is presented. In order to bring nanotechnology into industrial and commercial heating applications
Low loss and single mode metal dielectric hybrid-clad waveguides for Terahertz radiation
No full textSeveral waveguide solutions based on technologies from both electronics and photonics have been proposed for guiding Terahertz (THz) radiation. Hollow-core dielectric waveguides are one of the best options for guiding THz radiation since the material absorption is almost zero in the air-core. However, these waveguides are usually multimode and have dimensions in the order of a few millimeters. Here we propose a hollow-core waveguide with sub-wavelength scale metallic wires in the cladding for THz guidance. The theoretical studies show that such a hybrid cladding reflects the transverse magnetic (TM) waves and transmits the transverse electric (TE) waves, leading to a waveguide structure that only confines TM modes. The numerical simulations show a pure single mode, single polarization operation window from 0.22 THz to 0.34 THz and 14.8 dB/m propagation loss at 0.29 THz. Compared to a metallic waveguide with similar dimension, the proposed waveguide more than doubles the single mode operation bandwidth with comparable losses. We discuss the effect of optical and structural parameters of the hybrid cladding on the single mode operating window and propagation losses, and suggest methods of fabrication of the waveguide. The design principle of the proposed waveguide can be extended to the mid-inferred spectrum
Dipole-fiber systems: Radiation field patterns, effective magnetic dipoles, and induced cavity modes
No full textWe study the radiation patterns produced by a dipole placed at the surface of a nanofiber and oriented perpendicular to it, either along the radial (r-oriented) or azimuthal (Φ-oriented) directions. We find that the dipole induces an effective circular cavity-like leaky mode in the nanofiber. The first radiation peak of the Φ-oriented dipole contributes only to TE radiation modes, while the radiation of the r-oriented dipole is composed of both TE and TM radiation modes, with relative contribution depending on the refractive index of the nanofiber. We reveal that the field pattern of the first resonance of a Φ-oriented dipole is associated with a magnetic dipole mode and strong magnetic response of an optical nanofiber
Computing using delayed feedback systems: towards photonics
No full textinfo:eu-repo/semantics/publishe
Energy density characterization of complex ultrashort laser pulses
No full textWe introduce the concept of energy density flux as a characterization tool for the propagation of ultrashort laser pulses with spatio-temporal coupling. This energy density flux is calculated in the local frame moving at the velocity of the envelope of the wave packet under examination, and it can also be extended to the case of nonlinear propagation. We perform a detailed numerical study of the energy density flux in the particular case of conical waves. We also experimentally characterize the energy density flux for the cases of Bessel-X pulse in linear propagation and complex ultrashort pulses generated by filamentation in a nonlinear Kerr medium.</p
Oregon serious crime survey
No full textauthor, survey administration and data processing: Stan WoodwellCaption titleThis archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposesBureau of Justice Statistics, United States Department of Justice 80-BJ-CX-K009 82-BJ-CX-0002 82-BJ-CX-0014Mode of access: Internet from the Oregon Government Publications CollectionText in Englis
BJ-TSA-9, a Novel Human Tumor-Specific Gene, Has Potential as a Biomarker of Lung Cancer
No full textAbstractUsing bioinformatics, we have identified a novel tumorspecific gene BJ-TSA-9, which has been validated by Northern blot analysis and reverse transcriptionpolymerase chain reaction (RT-PCR). BJ-TSA-9 mRNA was expressed in 52.5% (21 of 40) of human lung cancer tissues and was especially higher in lung adenocarcinoma (68.8%). To explore the potential application of BJ-TSA-9 for the detection of circulating cancer cells in lung cancer patients, nested RT-PCR was performed. The overall positive detection rate was 34.3% (24 of 70) in peripheral blood mononuclear cells (PBMCs) of patients with various types of lung cancers and was 53.6% (15 of 28) in PBMCs of lung adenocarcinoma patients. In combination with the detection of two known marker genes SCC and LUNX, the detection rate was increased to 81.4%. A follow-up study was performed in 37 patients after surgical removal of tumor mass. Among nine patients with persistent detection of two to three tumor marker transcripts in PBMCs, six patients had recurrence/metastasis. In contrast, 28 patients with transient detection of one tumor marker or without detection of any tumor marker were all in remission. Thus, BJ-TSA-9 may serve as a marker for lung cancer diagnosis and as a marker, in combination with two other tumor markers, for the prediction of the recurrence and prognosis of lung cancer patients
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