Optics Commons^™

Exploring The Optimal Sensitivity Of Sum-Variance Nonseparability Criteria For Spin-1/2 Systems, Irfan Ali Khan, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We report on experimental and theoretical studies on recently introduced entanglement measures which use a sum of spin-variance criteria for two spin-1∕2 particles. Three inequalities are explored which exhibit useful concatenating properties. They are each shown to have greater sensitivities than a Bell’s measurement, while each requiring fewer measurements than a Bell’s measurement to obtain. The simplest inequality, requiring just four measurements, is shown to be efficient at testing for entanglement in down-conversion sources which naturally exhibit maximally polarized noise. The most complex inequality, requiring just 12 measurements, is shown to have a sensitivity equal to that of the Peres …

Medical Image Processing Using Transient Fourier Holography In Bacteriorhodopsin Films, Sri-Rajasekhar Kothapalli, Pengfei Wu, Chandra S. Yelleswarapu, D.V.G.L.N. Rao

Physics Faculty Publications

Real time image processing is demonstrated by recording and reconstructing the transient photoisomerizative grating formed in the bR film using Fourier holography. Desired spatial frequencies including both high and low band in the object beam are reconstructed by controlling the reference beam intensity. The results are in agreement with a theoretical model based on photoisomerization grating. We exploit this technique to process mammograms in real-time for identification of microcalcifications buried in the soft tissue for early detection of breast cancer. A feature of the technique is the ability to transient display of selected spatial frequencies in the reconstructing process which …

Bell’S Inequalities For Particles Of Arbitrary Spin In Fixed Analyzers, Ronen Mukamel, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We propose a new set of observables for experiments on entangled particles of arbitrarily large spin that produce significant Clauser-Horne-Shimony-Holt inequality violations for fixed analyzer settings over a wider range of spins than was previously possible. These observables are better suited for experiments where analyzer orientations must be chosen before the spin of the entangled particles is known, such as experiments using polarization entangled downconverted photons.

Wide Angle Decentered Lens Beam Steering For Infrared Countermeasures Applications, Jennifer L. Gibson, Bradley D. Duncan, Edward A. Watson, John S. Loomis

Electro-Optics and Photonics Faculty Publications

A beam-steering system consisting of three cemented achromatic doublets is presented. Intended for use in IR countermeasure applications, our system is designed to operate over the 2- to 5-μm spectrum with minimum angular dispersion. We show that dispersion can be minimized by using doublet lenses fashioned from AMTIR-1 and germanium. Our system is designed to be compact and lightweight, with no internal foci, while allowing steering to ±22.5 deg. We also maintain a minimum 2-in. clear aperture for all steering angles, and a nominal divergence of 1 mrad. Plane wave and Gaussian beam analyses of our system are presented.

Achromatic Angle-Insensitive Infrared Quarter-Wave Retarder Based On Total Internal Reflection At The Si–Sio2 Interface, R. M.A. Azzam, Cristina L. Spinu

Electrical Engineering Faculty Publications

An achromatic infrared (λ = 1.2–4 μm), Si-prism quarter-wave retarder (QWR) is described that uses total internal reflection at a buried Si–SiO₂ interface at an angle of incidence φ near 33°, where ∂Δ/∂φ = 0. The retardance Δ deviates from 90° by <±2° within a field of view of ±10° (in air) over the entire bandwidth. Because the SiO₂ layer at the base of the prism is optically thick, this QWR is unaffected by environmental contamination.

A Simple Design For An Electronic Speckle Pattern Interferometer, Thomas R. Moore

Faculty Publications

An electronic speckle pattern interferometer suitable for use in an undergraduate laboratory is described. This interferometer can be built for a small fraction of the cost of a commercial version and is simple and inexpensive to build and understand. The interferometer is useful for visualizing the normal modes of vibrating objects as well as changes in index of refraction.

Volume Holographic Recording And Readout For 90-Deg Geometry, Partha P. Banerjee, Monish Ranjan Chatterjee, Nickolai Kukhtarev, Tatiana Kukhtareva

Electrical and Computer Engineering Faculty Publications

When a prerecorded cross-beam hologram is reconstructed (so-called edge-lit readout) with a uniform plane wave and a point source, the resulting exact solutions reveal Bessel-function-type diffracted beam profiles, which are fundamentally modified under weak propagational diffraction. The case of a profiled beam readout with propagational diffraction may be analyzed using a transfer function approach based on 2-D Laplace transforms. In a second series of investigations, dynamic readout from a cross-beam volume hologram recorded with two orthogonal uniform plane waves is considered for various dependences of the refractive index modulation with intensity. Typically, refractive index profiles that are proportional to the …

Map Estimation For Hyperspectral Image Resolution Enhancement Using An Auxiliary Sensor, Russell C. Hardie, Michael T. Eismann, Gregory L. Wilson

Electrical and Computer Engineering Faculty Publications

This paper presents a novel maximum a posteriori (MAP) estimator for enhancing the spatial resolution of an image using co-registered high spatial-resolution imagery from an auxiliary sensor. Here we focus on the use of high-resolution panchomatic data to enhance hyperspectral imagery. However, the estimation framework developed allows for any number of spectral bands in the primary and auxiliary image. The proposed technique is suitable for applications where some correlation, either localized or global, exists between the auxiliary image and the image being enhanced. To exploit localized correlations, a spatially varying statistical model, based on vector quantization, is used. Another important …

Volume Holographic Optical Elements, Ching-Cherng Sun, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

The final two papers are concerned with the analysis of novel holograms. Banerjee et al. investigate holographic recording and reconstruction for edge-lit holograms recorded in a 90-degree geometry. Various cases of recording and readout that incorporate propagational diffraction have been modeled. It is shown that the 90-degree geometry can result in beam shaping, as evidenced through preliminary experimental results with photorefractive lithium niobate. Nguyen et al. propose a new approach for designing computer-generated holograms. An artificial neural network is used to initiate the genetic algorithm so that the high computation cost of genetic algorithms for synthesizing holograms is significantly reduced …

Femtosecond Spectrotemporal Magneto-Optics, J.-Y. Bigot, L. Guidoni, E. Beaurepaire, Peter N. Saeta

All HMC Faculty Publications and Research

A new method to measure and analyze the time and spectrally resolved polarimetric response of magnetic materials is presented. It allows us to study the ultrafast magnetization dynamics of a CoPt₃ ferromagnetic film. The analysis of the pump-induced rotation and ellipticity detected by a broad spectrum probe beam shows that magneto-optical signals predominantly reflect the spin dynamics in ferromagnets.

Phase Shifts That Accompany Total Internal Reflection At A Dielectric–Dielectric Interface, R. M.A. Azzam

Electrical Engineering Faculty Publications

The absolute, average, and differential phase shifts that p- and s-polarized light experience in total internal reflection (TIR) at the planar interface between two transparent media are considered as functions of the angle of incidence φ. Special angles at which quarter-wave phase shifts are achieved are determined as functions of the relative refractive index N. When the average phase shift equals π/2, the differential reflection phase shift Δ is maximum, and the reflection Jones matrix assumes a simple form. For N>√3, the average and differential phase shifts are equal (hence δ_p=3δ_s) at …

Hong-Ou-Mandel Cloning: Quantum Copying Without An Ancilla, Irfan Ali Khan, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this paper we report an experimental realization of an ancilla-free 1→2 phase-covariant quantum cloner. The cloner is realized by interfering a linearly polarized photon, which we wish to clone with a circularly polarized photon at a beam splitter. The two-photon effect can be understood in light of Hong-Ou-Mandel interference. The fidelity of the cloner was measured as 0.829±0.008 for the 0∕90 basis and 0.835±0.006 for the 45∕135 basis, which is in good agreement with the theoretical prediction of 5∕6 fidelity. The experimental scheme is straightforward and has a high cloning success rate.

Interferometric And Holographic Imaging Of Surface-Breaking Cracks, James Lawrence Blackshire, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

Two advanced nondestructive evaluation systems are developed for imaging surface-breaking cracks in aerospace materials. The systems use scanning heterodyne interferometry and frequency-translated holography principles to image ultrasonic displacement fields on material surfaces with high resolution and sensitivity. Surface-breaking cracks are detected and characterized by visualizing near-field ultrasonic scattering processes, which in turn results in local intensification of ultrasonic displacement fields in the immediate vicinity of a crack. The local intensification permits cracks to be easily distinguished from background levels, and creates unique displacement field images that follow the contours and morphology of the cracks with microscopic precision. The interferometric and …

Realization Of The Einstein-Podolsky-Rosen Paradox Using Momentum- And Position-Entangled Photons From Spontaneous Parametric Down Conversion, John C. Howell, Ryan S. Bennink, Sean J. Bentley, Robert W. Boyd

Mathematics, Physics, and Computer Science Faculty Articles and Research

We report on a momentum-position realization of the EPR paradox using direct detection in the near and far fields of the photons emitted by collinear type-II phase-matched parametric down conversion. Using this approach we achieved a measured two-photon momentum-position variance product of 0.01ℏ², which dramatically violates the bounds for the EPR and separability criteria.

Investigation Of The Diffusion Processes In Self-Processing Acrylamide-Based Photopolymer System, Izabela Naydenova, Raghavendra Jallapuram, Robert Howard, Suzanne Martin, Vincent Toal

Articles

Results from the investigation of the diffusion processes in a dry acrylamide-based photopolymer system are presented. The investigation is carried out in the context of experimental work on optimization of the high spatial frequency response of the photopolymer. Tracing the transmission holographic grating dynamics at short times of exposure is utilized to measure diffusion coefficients. The results reveal that two different diffusion processes contribute with opposite sign to the refractive index modulation responsible for the diffraction grating build up. Monomer diffusion from dark to bright fringe areas increases the refractive index modulation. It is characterized with diffusion constant D0=1.6E-7 cm2/s. …

Experimental Investigation Of A Rubidium-Argon Dual Species Magneto-Optical Trap, Hauke Christian Busch

Physics Theses & Dissertations

The first simultaneous cooling and confinement of two different atomic species from opposite sides of the periodic table in a dual magneto optical trap (DMOT) has been accomplished. The alkali-metal ⁸⁵Rb and the noble gas ⁴⁰Ar* have been simultaneously confined, characterized, and interspecies interaction parameters have been measured. The DMOT confined 1.2 × 10^{6 85}Rb atoms at a density of 1 × 10¹⁰/cm³ and 1.4 × 10^{6 40}Ar* atoms with a density of 1.2 × 10¹⁰/cm³. A collisional loss rate coefficient for Rb-Ar* has been determined to …

Application Of Photopolymer Holographic Gratings, Emilia Mihaylova, Izabela Naydenova, Hosam Sherif, Suzanne Martin, Vincent Toal

Conference Papers

Two optical set-ups for electronic speckle pattern shearing interferometry (ESPSI) using photopolymer diffractive optical elements are presented. Holographic gratings are recorded using an acrylamide based photopolymer material. Since the polymerisation process occurs during recording, the holograms are produced without any development or processing. In both ESPSI systems the photopolymer gratings are used to shear the image. In the first ESPSI system only one grating is used in combination with a sheet of ground glass. The distance between the grating and the ground glass can be used to control the amount of the shear. The sheared images on the ground glass …

Quantum And Classical Coincidence Imaging, Ryan S. Bennink, Sean J. Bentley, Robert W. Boyd, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

Coincidence, or ghost, imaging is a technique that uses two correlated optical fields to form an image of an object. In this work we identify aspects of coincidence imaging which can be performed with classically correlated light sources and aspects which require quantum entanglement. We find that entangled photons allow high-contrast, high-resolution imaging to be performed at any distance from the light source. We demonstrate this fact by forming ghost images in the near and far fields of an entangled photon source, noting that the product of the resolutions of these images is a factor of 3 better than that …

Study Of The Excited-State Absorption Properties Of Polymethine Molecules, Richard Stanley Lepkowicz

Electronic Theses and Dissertations

This dissertation investigates excited-state nonlinearities in a series of polymethine dyes for the application of nanosecond optical limiting. Optical limiters are devices that for low intensity light exhibit a high linear transmittance, but for high intensity light strongly attenuate the incident radiation. These devices would serve to protect optical sensors from intense laser radiation by clamping the maximum energy allowed through an optical system below the damage threshold of the sensor. The search is ongoing for optical materials that are both broadband and have high damage thresholds to be effective materials for limiting applications. Polymethine dyes are promising compounds due …

Advances In Pattern Recognition Algorithms, Architectures, And Devices, Mohammad S. Alam, Mohammad A. Karim

Division of Research and Economic Development Faculty & Staff Publications

Over the last decade, tremendous advances have been made in the general area of pattern recognition techniques, devices, and algorithms. We have had the distinct pleasure of witnessing this remarkable growth as evidenced through their dissemination in the previous Optical Engineering special sections we have jointly edited— January 1998, March 1998, May 2000, and January 2002. Twenty-six papers were finally accepted for this latest special section, encompassing the recent trends and advancements made in many different areas of pattern recognition techniques utilizing algorithms, architectures, implementations, and devices. These techniques include matched spatial filter based recognition, hit-miss transforms, invariant pattern recognition, …

Investigation Of The Photoinduced Surface Relief Modulation In Acrylamide-Based Photopolymer, Izabela Naydenova, Emilia Mihaylova, Suzanne Martin, Vincent Toal

Conference Papers

A surface relief diffraction grating is inscribed in acrylamide photopolymer by holographic recording with spatial frequency below 300 l/mm. The periodic surface modulation appears in addition to a volume phase holographic grating. Due to the nature of the presented photopolymerisable material the gratings are induced by light only and no post-processing is required. An investigation of the dependance of the amplitude of the photoinduced relief modulation on spatial frequency of recording and on sample thickness has been carried out utilising white light interferometry. A model of the mechanism of surface relief formation is proposed on the basis of the measured …

Electronic Speckle Pattern Shearing Interferometry Using Photopolymer Diffractive Optical Elements For Vibration Measurements, Emilia Mihaylova, Izabela Naydenova, Suzanne Martin, Vincent Toal

Conference Papers

Electronic speckle pattern shearing interferometry (ESPSI) is superior to Electronic speckle pattern interferometry (ESPI) when strain distribution, arising from object deformation or vibration, need to be measured. This is because shearography provides data directly related to the spatial derivatives of the displacement. Further development of ESPSI systems could be beneficial for wider application to the measurement of mechanical characteristics of vibrating objects. Two electronic speckle pattern shearing interferometers (ESPSI) suitable for vibration measurements are presented. In both ESPSI systems photopolymer holographic gratings are used to shear the images and to control the size of the shear. The holographic gratings are …

Chemical Structure - Nonlinear Optical Property Relationships For A Series Of Two-Photon Absorbing Fluorene Molecules, Joel Mccajah Hales

Electronic Theses and Dissertations

This dissertation reports on the investigation of two-photon absorption (2PA) in a series of fluorenyl molecules. Several current and emerging technologies exploit this optical nonlinearity including two-photon fluorescence imaging, three-dimensional microfabrication, site-specific photodynamic cancer therapy and biological caging studies. The two key features of this nonlinearity which make it an ideal candidate for the above applications are its quadratic dependence on the incident irradiance and the improved penetration into absorbing media that it affords. As a consequence of the burgeoning field which exploits 2PA, it is a goal to find materials that exhibit strong two-photon absorbing capabilities. Organic materials are …

Selective Mode Excitation In Specialty Waveguides Using Micro Optical, Waleed Mohammed

Electronic Theses and Dissertations

Although optical fibers and specialty waveguides are the base of majority of today's telecom and light delivery applications, fabrication deformation, nonlinearity and attenuation limit the bandwidth of the data being transmitted or the amount of power carried by these systems. One-way to overcome these limitations without changing the fibers design or fabrication is to engineer the input light in order to excite a certain mode or a group of modes with unique optical properties. Diffractive and micro optics are highly effective for selectively coupling light to specific modes. Using micro optics, mode selective coupling can be achieved through several matching …

Discrete Nonlinear Wave Propagation In Kerr Nonlinear Media, Joachim Meier

Electronic Theses and Dissertations

Discrete optical systems are a subgroup of periodic structures in which the evolution of a continuous electromagnetic field can be described by a discrete model. In this model, the total field is the sum of localized, discrete modes. Weakly coupled arrays of single mode channel waveguides have been known to fall into this class of systems since the late 1960's. Nonlinear discrete optics has received a considerable amount of interest in the last few years, triggered by the experimental realization of discrete solitons in a Kerr nonlinear AlGaAs waveguide array by H. Eisenberg and coworkers in 1998. In this work …

Endless Enlightenment: Eye-Operated Technology And The Political Economy Of Vision, Michael Gardiner

Reconstruction: Studies in Contemporary Culture

[First paragraph]

Despite a residual popular temptation to see the posts of cultural analysis as signs of temporal closure, the logic of global visual media is strengthening, not weakening, metaphors of visibility which remain intact from the Enlightenment. Here I describe a stand-off between post-Enlightenment critiques (as in some sectors of Cultural Studies) and a narrow power base which is defined by producing light and managing the very conditions of visibility. For the world's most powerful state, still strongly bound to its original Enlightenment foundations, intervention into other states' sovereignty is increasingly justified by evidence from spy planes (rather than …

Speed-Up Collisions In Strong-Field Double Ionization, Stanley L. Haan, J. C. Cully, K. Hoekema

University Faculty Publications and Creative Works

We compare quantum and classical models of double ionization (DI) for aligned-electron helium in strong laser fields, considering specifically the role of recollision processes in which the returning electron travels in the direction of the laser force. Quantum studies show that for the knee region in our model a small but persistent portion of the total DI occurs through these speed-up collisions. We show that classical modeling displays similar collisions and reveals that with-the-force doubly ionizing collisions typically involve two-particle trajectories in which both electrons can be said to have been bound or very nearly bound at the zero of …

Evaluation Of The Photo-Induced Structural Mechanisms In Chalcogenide, Cedric Lopez

Electronic Theses and Dissertations

Chalcogenide glasses and their use in a wide range of optical, electronic and memory applications, has created a need for a more thorough understanding of material property variation as a function of composition and in geometries representative of actual devices. This study evaluates compositional dependencies and photo-induced structural mechanisms in As-S-Se chalcogenide glasses. An effective fabrication method for the reproducible processing of bulk chalcogenide materials has been demonstrated and an array of tools developed, for the systematic characterization of the resulting material's physical and optical properties. The influence of compositional variation on the physical properties of 13 glasses within the …

Comparative Analysis Of Bragg Fibers, Shangping Guo, Sacharia Albin, Robert S. Rogowski

Electrical & Computer Engineering Faculty Publications

In this paper, we compare three analysis methods for Bragg fibers, viz. the transfer matrix method, the asymptotic method and the Galerkin method. We also show that with minor modifications, the transfer matrix method is able to calculate exactly the leakage loss of Bragg fibers due to a finite number of H/L layers. This approach is more straightforward than the commonly used Chew’s method. It is shown that the asymptotic approximation condition should be satisfied in order to get accurate results. The TE and TM modes, and the band gap structures are analyzed using Galerkin method.

Electronic Speckle Pattern Shearing Interferometer With A Photopolymer Holographyc Grating, Emilia Mihaylova, Izabela Naydenova, Suzanne Martin, Vincent Toal

Articles

A photopolymer holographic grating is used to produce the two sheared images in an electronic speckle pattern shearing interferometer. A ground glass screen following the grating serves the purpose of eliminating unwanted diffraction orders and to remove the requirement for the CCD camera to resolve the diffraction grating’s pitch. The sheared images on the ground glass are further imaged onto the CCD camera. The fringe pattern contrast was estimated to be above 90%. A validation of the system was done by comparing the theoretical phase difference distribution with the experimental data from the three point bending test.