Filters








190,202 Hits in 4.0 sec

Page 32 of The Trend in Engineering Vol. 9, Issue 3 [page]

1957 The Trend in Engineering  
In order to function well as a filter, the loaded guide would have to be reasonably well matched to the lines connecting both ends of the filter guide over the passbands.  ...  Thus, one possible use of this dielectric guide is a microwave bandpass or band-elimination filter.  ... 

Phase matching, quasi-phase matching, and pulse compression in a single waveguide for enhanced high-harmonic generation

Xiaoshi Zhang, Amy Lytle, Tenio Popmintchev, Ariel Paul, Nick Wagner, Margaret Murnane, Henry Kapteyn, Ivan P. Christov
2005 Optics Letters  
We demonstrate, for the first time to our knowledge, that the efficient region of high-harmonic generation can be shifted from lower to higher photon energies by combining phase matching, quasi-phase matching  ...  An intrawaveguide pulse compression process that works through a combination of ionization-induced refraction and guiding shortens the laser pulse as it propagates through an Ar-filled waveguide.  ...  matching at high energies owing to QPM and guiding of a shorter laser pulse that evolves in the waveguide.  ... 
doi:10.1364/ol.30.001971 pmid:16092236 fatcat:gnmbc3s4xzglndw7rwaexysh4m

High-speed optical signal processing potential of grating-coupled waveguide filters

R. R. A. Syms, S. Makrimichalou, A. S. Holmes
1991 Applied Optics  
It is first shown that such a device can act as its own matched filter for impulsive excitation, which allows its use as an encoder and decoder of ultrashort pulses.  ...  8 We demonstrate in this paper that a number of suitable guided-wave optical grating types already exist that may also be used as coherent matched filters.  ...  Fig. 1 . 1 All-optical encoding and decoding scheme for spread-spec- Fig. 3 . 3 (a) TE-TM mode converter filter, (b) an interwaveguide mode converter filter, and (c) a phase-matching diagram for gratingassisted  ... 
doi:10.1364/ao.30.003762 pmid:20706455 fatcat:suujeek5tjhx3jficql6pyitmq

Design considerations for a novel phase-contrast adaptive-optic wavefront sensor

Eric E. Bloemhof, James A. Westphal, Robert K. Tyson, Domenico Bonaccini, Michael C. Roggemann
2002 Adaptive Optics Systems and Technology II  
Such a WFS would be implemented by inserting a focal-plane filter with a π/2 phase-shifting central spot having a transverse size of the order of the diffraction limit.  ...  The phase-contrast approach might derive some advantages stemming from its more natural match to the control eigenvectors of the electrostrictive deformable mirrors that are expected to predominate in  ...  The filter has an additional optical thickness of π/2, and has a transverse size roughly matching the diffraction-limited spot size.  ... 
doi:10.1117/12.454812 fatcat:uokqtjekynb2zj5ppucnz53s3m

Analysis of the effect of radio frequency interference on interferometric phase

Bin Ding, Mao Sheng Xiang, Xing Dong Liang
2010 2010 IEEE International Geoscience and Remote Sensing Symposium  
(e) Matched filtering result in range after interpolation. (f) Matched filtering result in azimuth after interpolation.  ...  (e) Matched filtering result in range after 10 times interpolation. (f) Matched filtering result in azimuth after interpolation.  ... 
doi:10.1109/igarss.2010.5651776 dblp:conf/igarss/DingXL10 fatcat:6urjhygnkveypokxqpcrfx5zd4

Squeezing in a LiNbO3 integrated optical waveguide circuit

Gregory Kanter, Prem Kumar, Rostislav Roussev, Jonathan Kurz, Krishnan Parameswaran, Martin Fejer
2002 Optics Express  
The device integrates a secondharmonic-generation stage, waveguide couplers, spatial mode filters, and a degenerate-optical-parametric-amplification stage.  ...  These guides, therefore, behave similarly to single-moded devices, but the larger width ensures noncritical phase-matching, allowing for larger fabrication tolerances.  ...  The SH is also generated in its fundamental spatial mode due to the phase-matching condition.  ... 
doi:10.1364/oe.10.000177 pmid:19424347 fatcat:dfso6xtecjcqjcad7sv47ruppa

Phase-Matched Generation of Coherent Soft X-rays

A. Rundquist
1998 Science  
Fig. 1 . 1 Experimental set-up for phase-matching of soft x-rays in a capillary wave guide. The inset shows the growth of the x-ray wave when phase-matched.  ...  Because the fundamental wave guide mode is now phase-matched to create the x-ray output, the x-rays generated have excellent spatial properties.  ... 
doi:10.1126/science.280.5368.1412 pmid:9603725 fatcat:k4ofn3lsxjeardonqk772f7ygu

Content-Based Guided Image Filtering, Weighted Semi-Global Optimization, and Efficient Disparity Refinement for Fast and Accurate Disparity Estimation

Georgios A. Kordelas, Dimitrios S. Alexiadis, Petros Daras, Ebroul Izquierdo
2016 IEEE transactions on multimedia  
The pixel-based matching costs are filtered by applying guided image filtering, which relies on rectangular support windows of two different sizes.  ...  This paper presents a novel approach, which relies on content-based guided image filtering and weighted semi-global optimization for fast and accurate disparity estimation.  ...  The content-based guided image filtering in "Phase B" significantly enhances the initial disparity map.  ... 
doi:10.1109/tmm.2015.2505905 fatcat:mndclf2kf5atbdg3hcgbwbjioy

A Fast Trilateral Filter-Based Adaptive Support Weight Method for Stereo Matching

Dongming Chen, Mohsen Ardabilian, Liming Chen
2015 IEEE transactions on circuits and systems for video technology (Print)  
guided filter weight function produces a lower average error.  ...  The boundary strength at pixel p is defined as [3] , E(p) = ∑ θ (I(p) * F θ ,odd ) 2 + (I(p) * F θ ,even ) 2 , (5) where * denotes the convolution operator; the odd-phase filter F θ ,odd and even-phase  ... 
doi:10.1109/tcsvt.2014.2361422 fatcat:qihvdpo42vgeronrnjhta7cfb4

Combined matched filter and arbitrary interpolator for symbol timing synchronization in SDR receivers

Mehmood-ur-Rehman Awan, Peter Koch
2010 13th IEEE Symposium on Design and Diagnostics of Electronic Circuits and Systems  
This paper describes a low complexity multi-rate synchronizer that makes use of a polyphase filter bank to simultaneously perform matched-filtering and arbitrary interpolation for symbol timing synchronization  ...  Arbitrary Interpolation between available sample points is achieved by selecting the appropriate filter in the bank having the polyphase partitioned matched filter, which provides the optimal sampling  ...  In the first approach having separate interpolation and match filter, the timing error signal guides the interpolation filter re-sampling operation to achieve the timing synchronization.  ... 
doi:10.1109/ddecs.2010.5491797 dblp:conf/ddecs/AwanK10 fatcat:ysvc4lert5h5tjpiecu5dhn7u4

On-sky demonstration of matched filters for wavefront measurements using ELT-scale elongated laser guide stars

A. G. Basden, L. Bardou, D. Bonaccini Calia, T. Buey, M. Centrone, F. Chemla, J. L. Gach, E. Gendron, D. Gratadour, I. Guidolin, D. R. Jenkins, E. Marchetti (+9 others)
2017 Monthly notices of the Royal Astronomical Society  
We demonstrate use of a matched filter algorithm for the processing of elongated laser guide star (LGS) Shack-Hartmann images, using the CANARY adaptive optics instrument on the 4.2m William Herschel Telescope  ...  From the results of a first observing run, we show that the use of matched filtering improves our adaptive optics system performance, with increases in on-sky H-band Strehl measured up to about a factor  ...  Figure 5 . 5 A figure showing, for the 7 × 7 sub-apertures of the CANARY phase D LGS, (a) an on-sky matched filter x component, (b) the matched filter y component, (c) I 0 , (d) G x and (e) G y .  ... 
doi:10.1093/mnras/stx062 fatcat:xzodsxtlhnf3hamesezjvwoisu

Polymeric-waveguide-based integrated optical signal processing circuits

Xuejun Lu, Ray T. Chen, Achyut K. Dutta, Abdul Ahad S. Awwal, Niloy K. Dutta, Yasutake Ohishi
2004 Active and Passive Optical Components for WDM Communications IV  
In this paper, design examples such as dynamic channel equalizer, optical CDMA encoder and matched filter are analyzed. Simulation results are presented.  ...  The guiding multi-mode waveguide and the dumping planar waveguide, separated by a low-index polymer buffer layer, are designed to achieve phase-matches between the coupling mode of the guiding waveguide  ...  lossless; upper line: phase-mismatched lossless; lower line: phase-matched with loss of -6.5dB/cm; middle line: phased-mismatched with loss of -6.5dB/cm, oscillating line:phase-matched, no loss.  ... 
doi:10.1117/12.570804 fatcat:5wq2mkvqbbcb7jr2wxodtsc6dm

Corrugated horn design for HFI on PLANCK

J. A. Murphy
2002 AIP Conference Proceedings  
The modelling of the horns uses a rigorous electromagentic mode matching technique that is found to give good agreement with measurement.  ...  Careful modelling using the mode matching approach was therefore required to optimize the wave-guide filter operation for either single mode operation (where the wave-guide acts as the high pass filter  ...  The high frequency channels on the HFI employ multi-moded horns with the number of modes being determined by the wave-guide filter properties (guide radius and corrugation depths).  ... 
doi:10.1063/1.1475645 fatcat:agjedomko5h4tpohypldrckh7m

Frequency doubling in cavity-resonator integrated grating filter

Francois Renaud, Olivier Gauthier-Lafaye, Antoine Monmayrant, Evgeni Popov, Anne-Laure Fehrembach, Stéphane Calvez, Connie J. Chang-Hasnain, Weimin Zhou, Andrei Faraon
2020 High Contrast Metastructures IX  
However, their operation relies on a non-localized and large-area guided mode that limits the achievable power density and requires complex phase-matching approaches.  ...  Guided Mode Resonant Filters (GMRFs) have long been studied as a support surface for nonlinear optical interactions due to their intrinsically high Q-factor.  ...  INTRODUCTION Guided Mode Resonant Filters (GMRFs) have been studied as devices for nonlinear optical interactions due to their intrinsically high Q-factor 1, 2 .  ... 
doi:10.1117/12.2542771 fatcat:gfvhnzxuzvh7thoxnuyubeiqxi

GUIDED-MODE RESONANCE FILTER COMPENSATED TO OPERATE ON A CURVED SURFACE

Raymond C. Rumpf, Marvin Gates, Carrie L. Kozikowski, William A. Davis
2013 Progress In Electromagnetics Research C  
Guided-mode resonance filters (GMRFs) are highly compact structures that can produce a strong frequency response from a single thin layer of dielectric.  ...  Under a precise phase matching condition, the grating partially couples externally propagating waves into guided modes within the slab.  ...  When the applied wave is given some angle of incidence, the phase matching condition changes.  ... 
doi:10.2528/pierc13041209 fatcat:rsp3spgctbb7lomsa2et2qoud4
« Previous Showing results 1 — 15 out of 190,202 results