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modulation of the SPP wave in helical metal waveguide by geometry phase

EPL 2019年第4期125卷

作者： Jiang, Ran Gao, Qi Zhou, Yun-Song Zhao, Li-Ming Gao, Hua Capital Normal Univ Dept Phys Ctr Theoret Phys Beijing 100048 Peoples R China China Univ Geosci Sch Sci Beijing 100083 Peoples R China

This paper introduces a new way to modulate the surface plasmon polariton (SPP) wave, that is, the use of geometric phase modulation. A silver tube waveguide is designed to generate a geometric phase when the waveguide is wound into a solenoid. We use intuitive physical images instead of geometric formulas to obtain the geometric phase. The eigenfunctions of SPP in the helical waveguide are obtained theoretically. In order to exhibit the geometric phase effect, an ideal experiment is proposed, and the modulation of the energy flux of the 1st mode by the geometry phase is calculated. Copyright (C) EPLA, 2019

关键词： modulation and optical transfer functions Propagation, scattering, and losses, solitons Fiber waveguides, couplers, and arrays

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Modified Sagnac imaging spectropolarimeter for full linear Stokes parameters

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EPL 2018年第5期124卷

作者： Gao, Peng Hu, Xiaochen Guo, Guanghai Kang, Yongqiang Ai, Jingjing Wang, Xia Qingdao Univ Sci & Technol Shandong Adv Optoelect Mat & Technol Engn Lab Coll Math & Phys Sci Qingdao 266061 Peoples R China Shanxi Datong Univ Inst Solid State Phys Datong 037009 Peoples R China Xi An Jiao Tong Univ Sch Elect & Informat Engn Inst Space Opt Xian 710049 Shaanxi Peoples R China

A modified Sagnac imaging spectropolarimeter is conceptually described. It consists of a spectral-polarimetric modulator, a modified Sagnac interferometer with large optical path difference, and a CCD camera. This design modulates the Stokes components of the input light into different wave numbers and obtains the modulated interferogram in snapshot mode, and the spectra or the Stokes components can be separated awl demodulated from the interferogram. The performance of the system is demonstrated through a numerical simulation, and a novel method is proposed to detect the polarization parameters including the degree of polarization and polarization direction for eliminating the aliasing effects between linear Stokes parameters. Compared with the existing imaging spectrometers, the modified Sagnac imaging spectropolarimeter can acquire one-dimensional spatial information and its full linear spectropolarimetric information in one exposure, and sonic other spatial information can be obtained by push-broom mode.

关键词： Imaging and optical processing modulation and optical transfer functions Image forming and processing

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Design of eye models used in quantitative analysis of interaction between chromatic and higher-order aberrations of eye

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OPTICS COMMUNICATIONS 2014年 332卷 89-95页

作者： Zhai, Yi Wang, Yan Wang, Zhaoqi Liu, Yongji Zhang, Lin He, Yuanqing Chang, Shengjiang Nankai Univ Inst Modern Opt Tianjin 300071 Peoples R China Minist Educ Key Lab Opt Informat Sci & Technol Tianjin 300071 Peoples R China Tianjin Med Univ Tianjin Eye Hosp Tianjin 300020 Peoples R China Tianjin Med Univ Inst Eye Tianjin Key Lab Ophthalmol & Visual Sci Tianjin 300020 Peoples R China

Special kinds of eye models are constructed by means of optical system design to quantitatively investigate impacts of longitudinal chromatic aberration (LCA), transverse chromatic aberration (TCA) and LCA+TCA on retina image quality and on depth of focus (DOF), as well as interaction between chromatic and higher-order aberrations. Results show that LCA plays a main role in enhancement of DOF and higher-order aberrations further increase DOE For most of the eyes the impact of higher-order aberrations on vision is much smaller than that of LCA+TCA and the presence of LCA+TCA further reduces the impact of higher-order aberrations. The impact of LCA approximates to that of LCA+TCA, and the impact of TCA approximates to that of normal level of higher-order aberrations and is negligible. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Anatomy and optics of eye optical system design Color vision modulation and optical transfer functions

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optical phase-locked loop with fibre lasers for low phase noise millimetre-wave signal generation

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ELECTRONICS LETTERS 2009年第17期45卷 878-879页

作者： Hyodo, M. Saito, S. Kasai, Y. Natl Inst Informat & Commun Technol Kobe Adv ICT Res Ctr Kobe Hyogo 6512492 Japan Natl Inst Informat & Commun Technol Appl Electromagnet Res Ctr Koganei Tokyo 1848795 Japan

An optical phase-locked loop (OPLL) using two continuous-wave commercial fibre lasers was implemented by means of pump power modulation. Although the 3 dB bandwidth of the frequency modulation transfer function of a fibre laser was measured to be approximately 6 kHz, the control bandwidth of the loop was extended by a factor of 10 using electronic phase-lead compensation. The operation of our OPLL was stable with a residual RMS phase fluctuation of 57 mrad. By using this technique, the photonic generation of millimetre-wave signals up to 64 GHz was successfully demonstrated.

关键词： low phase noise millimetre-wave signal generation Fibre lasers and amplifiers frequency modulation transfer function modulation and optical transfer functions optical phase locked loops electronic phase-lead compensation Signal generators fibre lasers mode locking and tuning pump power modulation signal generators optical phase-locked loop Laser beam modulation, pulsing and switching low-power electronics optical communication optical transfer function phase noise

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In-band noise suppression using novel monolithically integrated semiconductor optical amplifier-based ultra-compact interferometers

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IET OPTOELECTRONICS 2008年第3期2卷 105-110页

作者： Moll, E. Reading-Picopoulos, D. Williams, K. A. Penty, R. V. White, I. H. Univ Cambridge Dept Engn Ctr Photon Syst Ctr Adv Photon & Elect Cambridge CB3 0AF England

Novel all-optical noise suppressors based on the nonlinear transfer function properties of monolithically integrated active waveguide interferometers are proposed and demonstrated. Through a power map imbalance between the two arms of the interferometers, each of which contains multi-contact semiconductor optical amplifiers, a nonlinear transfer function is created, which can then be exploited to achieve in-band noise suppression. The authors demonstrate the use of such a mechanism in ultra-compact Mach-Zehnder and Michelson interferometers (MIs). Experimental work demonstrates a 5.0 dB optical signal-to-noise ratio improvement for the Mach-Zehnder and an 8.4 dB improvement for the MIs, respectively. It is shown that for input data the Mach-Zehnder is capable of providing a Q factor improvement of 4.1 dB. To the authors' knowledge, these devices constitute the smallest integrated interferometer structures reported to date demonstrating in-band noise suppression.

关键词： in-band noise suppression power map imbalance optical waveguides optical transfer function monolithically integrated semiconductor optical amplifier ultra-compact interferometers monolithic integrated circuits semiconductor optical amplifiers Nonlinear and functional equations (numerical analysis) Semiconductor lasers nonlinear transfer function properties Integrated optoelectronics Michelson interferometers optical noise optical signal-to-noise ratio all-optical noise suppressors Lasing action in semiconductors nonlinear functions multicontact SOA Q factor improvement Mach-Zehnder interferometers optical interferometry optical waveguide components active waveguide interferometers modulation and optical transfer functions optical waveguides and couplers integrated optoelectronics interference suppression

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High temperature Fabry-Perot probe interrogated with tunable fibre ring laserl

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ELECTRONICS LETTERS 2008年第15期44卷 898-899页

作者： Jackson, D. A. Univ Kent Sch Phys Sci Canterbury Kent England

A high temperature fibre-optic based probe is described based on a miniature Fabry-Perot with a maximum operating temperature of similar to 700 degrees C limited by the gold coated fibre transceiver link connecting the optical source to the probe. It was interrogated by a tunable fibre laser which could be linearly or sinusoidally toned at scanning rates of 2 and 20 kHz, respectively. The transfer function of the system is in the form of channelled spectra rather than the usual interference fringes observed for interferometric sensors. The periodicity of the 'channelled spectra fringes' is governed by the Fabry-Perot free spectral range which is related to the inverse of the probe temperature.

关键词： Fabry-Perot interferometers micro-optics integrated optics fibre lasers Thermal variables measurement Laser beam modulation, pulsing and switching probes ring lasers interferometric sensors optical transfer function Fibre lasers and amplifiers laser tuning Thermometry tunable fibre ring laser Fibre optic sensors temperature sensors fibre gyros Integrated optics high temperature miniature Fabry-Perot probe mode locking and tuning Micro-optical devices and technology high temperature fibre-optic based probe modulation and optical transfer functions channelled spectra fringe periodicity temperature measurement fibre optic sensors interference fringes optical interferometry Laser resonators and cavities transfer function gold coated fibre transceiver link

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Choice of data types in time resolved fluorescence enhanced diffuse optical tomography

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MEDICAL PHYSICS 2007年第12期34卷 4890-4900页

作者： Riley, Jason Hassan, Moinuddin Chernomordik, Victor Gandjbakhche, Amir NICHHD Lab Integrat & Med Biophys Natl Inst Hlth Bethesda MD 20892 USA

In this paper we examine possible data types for time resolved fluorescence enhanced diffuse optical tomography (FDOT). FDOT is a particular case of diffuse optical tomography, where our goal is to analyze fluorophores deeply embedded in a turbid medium. We focus on the relative robustness of the different sets of data types to noise. We use an analytical model to generate the expected temporal point spread function (TPSF) and generate the data types from this. Varying levels of noise are applied to the TPSF before generating the data types. We show that local data types are more robust to noise than global data types, and should provide enhanced information to the inverse problem. We go on to show that with a simple reconstruction algorithm, depth and lifetime (the parameters of interest) of the fluorophore are better reconstructed using the local data types. Further we show that the relationship between depth and lifetime is better preserved for the local data types, suggesting they are in some way not only more robust, but also self-regularizing. We conclude that while the local data types may be more expensive to generate in the general case, they do offer clear advantages over the standard global data types.

关键词： Visual imaging Image reconstruction tomography Image analysis modulation and optical transfer functions Inverse problems biomedical optical imaging fluorescence image enhancement image reconstruction inverse problems medical image processing optical tomography optical transfer function Medical image noise Fluorescence Medical imaging Image reconstruction Poisson's equation Inverse problems Tomography Time measurement Time resolved spectroscopy optical imaging

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An image quality comparison of standard and dual-side read CR systems for pediatric radiology

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MEDICAL PHYSICS 2006年第2期33卷 411-420页

作者： Monnin, P Holzer, Z Wolf, R Neitzel, U Vock, P Verdun, FR Univ Lausanne IRA CH-1007 Lausanne Switzerland Univ Hosp Bern Inselspital Inst Paediat Radiol CH-3010 Bern Switzerland Philips Med Syst DMC GmbH D-22335 Hamburg Germany CHU Vaudois Univ Hosp Ctr CH-1011 Lausanne Switzerland

An objective analysis of image quality parameters was performed for a computed radiography (CR) system using both standard single-side and prototype dual-side read plates. The pre-sampled modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) for the systems were determined at three different beam qualities representative of pediatric chest radiography, at an entrance detector air kerma of 5 mu Gy. The NPS and DQE measurements were realized under clinically relevant x-ray spectra for pediatric radiology, including x-ray scatter radiations. Compared to the standard single-side read system, the MTF for the dual-side read system is reduced, but this is offset by a significant decrease in image noise, resulting in a marked increase in DQE (+40%) in the low spatial frequency range. Thus, for the same image quality, the new technology permits the CR system to be used at a reduced dose level. (c) 2006 American Association of Physicists in Medicine.

关键词： Radiography modulation and optical transfer functions Non-ionizing radiation equipment and techniques diagnostic radiography optical transfer function paediatrics biomedical equipment modulation transfer functions Medical imaging Medical image noise Computed radiography X-ray scattering Phosphors Image detection systems Image sensors Medical X-ray imaging Medical image quality

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Performance evaluation of a computed radiography imaging device using a typical "front side" and novel "dual side" readout storage phosphors

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MEDICAL PHYSICS 2006年第2期33卷 290-296页

作者： Fetterly, KA Schueler, BA Mayo Clin Dept Diagnost Radiol Rochester MN 55905 USA

The Fourier-space modulation transfer function (MTF), normalized noise power spectrum (nNPS), and detective quantum efficiency (DQE) of a computed radiography (CR) x-ray imaging device were measured. Two different storage phosphor screens were used in conjunction with a single CR reader (Fuji, Clearview, CS). One of the storage phosphor plates (ST-BD) had a clear backing material which allowed "dual side read" of the latent image from both the "front" and "back" sides of the phosphor. The other phosphor plate had a light occluding backing material, limiting the readout to front side only (ST-VI). The standard RQA-5 beam quality was used. The MTF was measured using a 1 mm thick tungsten edge device. Compared to the ST-55BD phosphor, the ST-VI phosphor was found to have modestly higher MTF at all spatial frequencies. The nNPS(f) and DQE(f) were measured for nominal incident exposure levels ranging from 0.1 to 10 mR. The dual side read phosphor demonstrated superior DQE, especially at low spatial frequencies. At the frequency 0.5 cycles/mm, the DQE values for the 1 mR exposure were 0.36 and 0.21 for the ST-55BD and ST-VI phosphor plates, respectively. The differences between the spatial-frequency dependent DQE of the two plates can be attributed to the increased signal collection efficiency of the dual side read plates and differences in storage phosphor structure noise. (c) 2006 American Association of Physicists in Medicine.

关键词： Radiography Digital radiography modulation and optical transfer functions Image quality Non-ionizing radiation equipment and techniques Fourier analysis diagnostic radiography computerised tomography phosphors optical transfer function Fourier transforms computed radiography detective quantum efficiency modulation transfer function noise power spectrum Phosphors modulation transfer functions Medical image noise Medical imaging Computed radiography X-ray imaging Medical X-ray imaging Machinery noise X-ray optics Image analysis

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Flattening filter based on cascaded dual concentric core fibres

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ELECTRONICS LETTERS 2005年第4期41卷 170-171页

作者： Février, S Gérôme, F Auguste, JL Blondy, JM Univ Limoges CNRS UMR 6615 Inst Rech Commun Opt & Microondes F-87060 Limoges France

The use of dual concentric core fibres to realise a flattening filter is reported. The power spectrum of an ASE source has been flattened in the C-band from 5.8 to 1.4 dB.

关键词： modulation and optical transfer functions optical transfer function optical coatings and filters power spectrum flattening filter cascaded dual concentric core fibres Spectral and other filters C-band optical fibre filters refractive index ASE source Fibre optics

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