Browsing by Keywords "Optics"
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83 W, 1 ns, 3.1 MHz allfiber laser for micromachining
(2011)Fiber lasers are commonly used for various material processing applications. The advantages (such as simplicity of the system, high material removal rate) and disadvantages (larger heataffected zone, reduced precision) ... 
About the Wigner distribution of a graded index medium and the fractional fourier transform operation
(S P I E  International Society for Optical Engineering, 1993)Upon propagation through quadratic graded index media, the Wigner distribution of the wavefunction of light rotates uniformly. As a consequence, a definition of fractional Fourier transforms based on rotating the functions ... 
Beyond Nyquist sampling: a costbased approach
(Optical Society of America, 2013)A samplingbased framework for finding the optimal representation of a finite energy optical field using a finite number of bits is presented. For a given bit budget, we determine the optimum number and spacing of the ... 
Directional selectivity through the subwavelength slit in metallic gratings
(2011)An approach for obtaining strong directional selectivity through a single subwavelength slit in nonsymmetric metallic gratings is shown theoretically and experimentally. Directionality effect originates from the different ... 
Effect of spatial distribution of partial information on the accurate recovery of optical wave fields
(Optical Society of America, 2017)We consider the problem of recovering a signal from partial and redundant information distributed over two fractional Fourier domains. This corresponds to recovering a wave field from two planes perpendicular to the direction ... 
Electron momentum and energy relaxation rates in GaN and AlN in the highfield transport regime
(The American Physical Society, 2003)Momentum and energy relaxation characteristics of electrons in the conduction band of GaN and AlN are investigated using two different theoretical approaches corresponding to two high electricfield regimes, one up to 12 ... 
Fast and accurate algorithms for quadratic phase integrals in optics and signal processing
(SPIE, 2011)The class of twodimensional nonseparable linear canonical transforms is the most general family of linear canonical transforms, which are important in both signal/image processing and optics. Application areas include ... 
Förstertype nonradiative energy transfer directed from colloidal quantum dots to epitaxial quantum wells for light harvesting applications
(2011)We report on Frstertype nonradiative energy transfer directed from CdSe/ZnS core/shell quantum dots to InGaN/GaN quantum wells with 69.6% efficiency at 1.527 ns1 rate at room temperature for potential light harvesting ... 
Fractional Fourier transforms and their optical implementation: I
(Optical Society of America, 1993)Fourier transforms of fractional order a are defined in a manner such that the common Fourier transform is a special case with order a = 1. An optical interpretation is provided in terms of quadratic graded index media and ... 
Grating coupler integrated photodiodes for plasmon resonance based sensing in fluidic systems
(IEEE, 2011)We demonstrate an integrated sensor combining a gratingcoupled plasmon resonance surface with a planar photodiode. Plasmon enhanced transmission is employed as a sensitive refractive index (RI) sensing mechanism and ... 
Image representation and compression with the fractional Fourier transform
(Elsevier, 20010401)We discuss the application of fractional Fourier transformbased filtering configurations to image representation and compression. An image can be approximately represented (and stored or transmitted) as the coefficients ... 
Infrared digital holography applications for virtual museums and diagnostics of cultural heritage
(2011)Infrared digital holograms of different statuettes are acquired. For each object, a sequence of holograms is recorded rotating the statuette with an angular step of few degrees. The holograms of the moving objects are used ... 
Linear algebraic theory of partial coherence: discrete fields and measures of partial coherence
(SPIE  International Society for Optical Engineering, 2003)We present a linear algebraic theory of partial coherence which allows precise mathematical definitions of concepts such as coherence and incoherence. This not only provides new perspectives and insights, but also allows ... 
Memoryefficient multilevel physical optics algorithm for fast computation of scattering from threedimensional complex targets
(2007)Multilevel physical optics (MLPO) algorithm provides a speedup for computing the physicaloptics integral over complex bodies for a range of aspect angles and frequencies. On the other hand, when computation of the RCS ... 
Negative phase advance in polarization independent, multilayer negativeindex metamaterials
(Optical Society of American (OSA), 2008)We demonstrate a polarization independent negativeindex metamaterial (NIM) at microwave frequencies. Transmission measurements and simulations predict a lefthanded transmission band with negative permittivity and negative ... 
Negative refraction and subwavelength focusing using lefthanded composite metamaterials
(2008)We review experimental studies performed on lefthanded metamaterials (LHM) at microwave frequencies. The metamaterial structure is composed of periodic arrays of splitring resonators and wire meshes and exhibits a ... 
On the elemination of infinities in the PO component of equivalent edge currents
(Elsevier, 1993)Equivalent edge currents for the Physical Optics (PO) contribution to the edge diffraction are derived by choosing a proper coordinate system for a half plane. It is seen that these expressions for the PO component are ... 
Optimal Filtering with Linear Canonical Transformations
(Elsevier BV * NorthHolland, 19970201)Optimal filtering with linear canonical transformations allows smaller meansquare errors in restoring signals degraded by linear time or spacevariant distortions and nonstationary noise. This reduction in error comes ... 
Properties of a microjouleclass fiber oscillator modelocked with a SESAM
(2011)Energy scaling of ultrafast Ybdoped fiber oscillators has experienced rapid progress largely driven by many applications that require high average power femtosecond pulses. The fundamental challenge for ultrafast fiber ... 
SeaSpider: Automated information gathering on vessel movements in support of marine intelligence, surveillance, and reconnaissance
(2008)SeaSpider is an R&D tool to investigate the development of a software agent that would aid an operator in gathering information about marine vessels from public sources on the Internet. This information would supplement ...