Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
-
- Holography (3)
- Acrylamide based photopolymer (2)
- Surface relief gratings (2)
- Acrylamide (1)
- Carotenoid (1)
-
- Coherence and statistical optics (1)
- Communication wavelengths (1)
- Deprivation (1)
- Diet (1)
- Diffraction gratings (1)
- Diffusion (1)
- ESPSI (1)
- Electro-optics Program (1)
- Electromagnetic-waves (1)
- HOE (1)
- Holographic grating (1)
- Imaging systems (1)
- Inorganic nanoparticles (1)
- Macular (1)
- Medical optics and biotechnology (1)
- Monomer (1)
- Optical coherence tomography (1)
- Photopolymer (1)
- Photopolymers (1)
- Pigment (1)
- Shearing interferometry (1)
- Shrinkage of photopolymers (1)
- Switchable LC diffraction grating (1)
- Switchable LC diffraction gratings (1)
Articles 1 - 19 of 19
Full-Text Articles in Physics
Slow Light With Large Fractional Delays By Spectral Hole-Burning In Rubidium Vapor, Ryan M. Camacho, Michael V. Pack, John C. Howell
Slow Light With Large Fractional Delays By Spectral Hole-Burning In Rubidium Vapor, Ryan M. Camacho, Michael V. Pack, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We report on the experimental realization of large fractional pulse delays in a hot, Doppler-broadened rubidium vapor. A pump laser burns a deep spectral hole in the inhomogeneously broadened vapor. The delay is shown to be widely tunable by both power broadening the resonance and frequency modulating the pump laser. The simplicity of the scheme opens up the possibility for practical optical delays and buffers.
Investigation Of Negative Refractive Index In Reciprocal Chiral Materials, Monish Ranjan Chatterjee, Partha P. Banerjee, Pradeep R. Anugula
Investigation Of Negative Refractive Index In Reciprocal Chiral Materials, Monish Ranjan Chatterjee, Partha P. Banerjee, Pradeep R. Anugula
Electrical and Computer Engineering Faculty Publications
It is well known that there exist both natural materials (such as milk or sugar solution) possessing chiral (or handed) properties, as well as an increasing list of man-made materials (such as sodium bromate) that exhibit chirality. One of the principal properties of chirality is that light of any arbitrary polarization, when propagating through a chiral material, splits up into two circular polarizations propagating in different directions. In the past decade or longer, researchers have investigated electromagnetic transverse (plane) wave propagation across a non-chiral/chiral interface, and determined the electromagnetic Fresnel coefficients for such propagation. Traditionally, such coefficients are derived under …
Transients Of The Electromagnetically-Induced-Transparency-Enhanced Refractive Kerr Nonlinearity: Theory, M. V. Pack, R. M. Camacho, John C. Howell
Transients Of The Electromagnetically-Induced-Transparency-Enhanced Refractive Kerr Nonlinearity: Theory, M. V. Pack, R. M. Camacho, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We present a theory describing the transients and rise times of the refractive Kerr nonlinearity which is enhanced using electromagnetically induced transparency (EIT). We restrict our analysis to the case of a pulsed signal field with continuous-wave EIT fields, and all fields are well below saturation. These restrictions enable the reduction of an EIT Kerr, four-level, density-matrix equation to a two-level Bloch-vector equation which has a simple and physically intuitive algebraic solution. The physically intuitive picture of a two-level Bloch vector provides insights that are easily generalized to more complex and experimentally realistic models. We consider generalization to the cases …
Low-Distortion Slow Light Using Two Absorption Resonances, Ryan M. Camacho, Michael V. Pack, John C. Howell
Low-Distortion Slow Light Using Two Absorption Resonances, Ryan M. Camacho, Michael V. Pack, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We consider group delay and broadening using two strongly absorbing and widely spaced resonances. We derive relations which show that very large pulse bandwidths coupled with large group delays and small broadening can be achieved. Unlike single resonance systems, the dispersive broadening dominates the absorptive broadening which leads to a dramatic increase in the possible group delay. We show that the double resonance systems are excellent candidates for realizing all-optical delay lines. We report on an experiment which achieved up to 50 pulse delays with 40% broadening.
Role Of Beat Noise In Limiting The Sensitivity Of Optical Coherence Tomography, Richard C. Haskell, David Liao, Adam E. Pivonka, Tera L. Bell, Brendan R. Haberle, Barbara M. Hoeling, Daniel C. Petersen
Role Of Beat Noise In Limiting The Sensitivity Of Optical Coherence Tomography, Richard C. Haskell, David Liao, Adam E. Pivonka, Tera L. Bell, Brendan R. Haberle, Barbara M. Hoeling, Daniel C. Petersen
All HMC Faculty Publications and Research
The sensitivity and dynamic range of optical coherence tomography (OCT) are calculated for instruments utilizing two common interferometer configurations and detection schemes. Previous researchers recognized that the performance of dual-balanced OCT instruments is severely limited by beat noise, which is generated by incoherent light backscattered from the sample. However, beat noise has been ignored in previous calculations of Michelson OCT performance. Our measurements of instrument noise confirm the presence of beat noise even in a simple Michelson interferometer configuration with a single photodetector. Including this noise, we calculate the dynamic range as a function of OCT light source power, and …
Erratum: Exploring The Optimal Sensitivity Of Sum-Variance Nonseparability Critera For Spin-1/2 Systems, Irfan Ali Khan, John C. Howell
Erratum: Exploring The Optimal Sensitivity Of Sum-Variance Nonseparability Critera For Spin-1/2 Systems, Irfan Ali Khan, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
No abstract provided.
Phase Shifts In Frustrated Total Internal Reflection And Optical Tunneling By An Embedded Low-Index Thin Film, R. M.A. Azzam
Phase Shifts In Frustrated Total Internal Reflection And Optical Tunneling By An Embedded Low-Index Thin Film, R. M.A. Azzam
Electrical Engineering Faculty Publications
Simple and explicit expressions for the phase shifts that p- and s-polarized light experience in frustrated total internal reflection (FTIR) and optical tunneling by an embedded low-index thin film are obtained. The differential phase shifts in reflection and transmission Δr,Δt are found to be identical, and the associated ellipsometric parameters ψr,ψt are governed by a simple relation, independent of film thickness. When the Fresnel interface reflection phase shifts for the pand s polarizations or their average are quarter-wave, the corresponding overall reflection phase shifts introduced by the embedded layer are also quarter-wave for all values of film …
Experimental Demonstration Of High Two-Photon Time-Energy Entanglement, Irfan Ali Khan, John C. Howell
Experimental Demonstration Of High Two-Photon Time-Energy Entanglement, Irfan Ali Khan, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We report on the experimental demonstration of high energy-time entanglement in two-photon states created in the process of spontaneous parametric down-conversion. We show that the classical variance product, which we violate by three orders of magnitude, actually represents a lower bound estimate of the number of information eigenmodes K. Explicit measurements estimate K to be greater than 100, with theoretical estimates predicting a value of as high as 1×106. These results provide incentive for the practical feasibility of large bandwidth quantum information processing, particularly in cryptography over large distances.
Fast Ground State Manipulation Of Neutral Atoms In Microscopic Optical Traps, D. D. Yavuz, P. B. Kulatunga, E. Urban, Todd A. Johnson, N. Proite, T. Henage, T. G. Walker, M. Saffman
Fast Ground State Manipulation Of Neutral Atoms In Microscopic Optical Traps, D. D. Yavuz, P. B. Kulatunga, E. Urban, Todd A. Johnson, N. Proite, T. Henage, T. G. Walker, M. Saffman
Physics Faculty Publications
We demonstrate Rabi flopping at MHz rates between ground hyperfine states of neutral 87Rb atoms that are trapped in two micron sized optical traps. Using tightly focused laser beams we demonstrate high fidelity, site specific Rabi rotations with cross talk on neighboring sites separated by 8 μm at the level of 10−3. Ramsey spectroscopy is used to measure a dephasing time of 870 μs, which is ≈5000 times longer than the time for a π/2 pulse.
Two Way Diffusion Model For The Recording Mechanism In A Self-Developing Dry Acrylamide Photopolymer, Suzanne Martin, Izabela Naydenova, Raghavendra Jallapuram, Robert Howard, Vincent Toal
Two Way Diffusion Model For The Recording Mechanism In A Self-Developing Dry Acrylamide Photopolymer, Suzanne Martin, Izabela Naydenova, Raghavendra Jallapuram, Robert Howard, Vincent Toal
Conference Papers
In our most recent study [1] diffusion constants were measured in the simplified monoacrylamide version of a dry acrylamide based photopolymer holographic recording material developed in the Centre for Industrial and Engineering Optics. In this paper we report diffusion constants for the commonly used photopolymer formulation, which also contains the crosslinker bisacrylamide. A physical model for the recording mechanism is proposed which explains the two way diffusion observed in both systems, and is in agreement with much of the previously observed behaviour of the material, particularly in regard to dependence of diffraction efficiency growth on spatial frequency and persistence of …
Characterization Of An Acrylamide Based Photopolymer For Fabrication Of Liquid Crystal Devices, Pavani Kotakonda, Izabela Naydenova, Suzanne Martin, Vincent Toal
Characterization Of An Acrylamide Based Photopolymer For Fabrication Of Liquid Crystal Devices, Pavani Kotakonda, Izabela Naydenova, Suzanne Martin, Vincent Toal
Conference Papers
Photopolymers are increasingly interesting as new materials for the fabrication of electro optical liquid crystal devices. Photoinduced surface relief gratings in dry, self developing acrylamide based photopolymers can be used to align liquid crystals (LCs) as an alternative to the rubbing technique. These optically recorded surface relief patterns can be used to fabricate electro-optical switchable LC Bragg gratings. An investigation of the dependence of photoinduced surface relief gratings on recording intensity and thickness of the photopolymer layer is reported. The surface relief gratings were filled with E7 LCs and a switchable LC diffraction grating was fabricated.
Characterization Of An Acrylaminde Based Photopolymer For Fabrication Of Liquid Crystal Devices, Pavani Kotakonda
Characterization Of An Acrylaminde Based Photopolymer For Fabrication Of Liquid Crystal Devices, Pavani Kotakonda
Conference Papers
Photopolymers are increasingly interesting as new materials for the fabrication of electro optical liquid crystal devices. Photoinduced surface relief gratings in dry, self developing acrylamide based photopolymers can be used to align liquid crystals (LCs) as an alternative to the rubbing technique. These optically recorded surface relief patterns can be used to fabricate electro-optical switchable LC Bragg gratings. An investigation of the dependence of photoinduced surface relief gratings on recording intensity and thickness of the photopolymer layer is reported. The surface relief gratings were filled with E7 LCs and a switchable LC diffraction grating was fabricated.
Pocket Deformable Mirror For Adaptive Optics Applications, Leonid A. Beresnev, Mikhail Vorontsov, Peter Wangsness
Pocket Deformable Mirror For Adaptive Optics Applications, Leonid A. Beresnev, Mikhail Vorontsov, Peter Wangsness
Electrical and Computer Engineering Faculty Publications
Adaptive/active optical elements are designed to improve optical system performance in the presence of phase aberrations. For atmospheric optics and astronomical applications, an ideal deformable mirror should have sufficient frequency bandwidth for compensation of fast changing wave front aberrations induced by either atmospheric turbulences or by turbulent air flows surrounding a flying object (air optical effects). In many applications, such as atmospheric target tracking, remote sensing from flying aircraft, boundary layer imaging, laser communication and laser beam projection over near horizontal propagation paths the phase aberration frequency bandwidth can exceed several kHz. These fast-changing aberrations are currently compensated using relatively …
Adaptive Beam Director For A Tiled Fiber Array, Mikhail Vorontsov, Jim F. Riker, Ernst Polnau, Svetlana Lachinova, Venkata S. Rao Gudimetla
Adaptive Beam Director For A Tiled Fiber Array, Mikhail Vorontsov, Jim F. Riker, Ernst Polnau, Svetlana Lachinova, Venkata S. Rao Gudimetla
Electrical and Computer Engineering Faculty Publications
We present the concept development of a novel atmospheric compensation system based on adaptive tiled fiber array architecture operating with target-in-the-loop scenarios for directed beam applications. The adaptive tiled fiber array system is integrated with adaptive beam director (ABD). Wavefront control and sensing functions are performed directly on the beam director telescope primary mirror. The beam control of the adaptive tiled fiber array aims to compensate atmospheric turbulence-induced dynamic phase aberrations and results in a corresponding brightness increase on the illuminated extended object. The system is specifically designed for tiled fiber system architectures operating in strong intensity scintillation and speckle-modulation …
Enhanced Cerenkov Second-Harmonic Generation In Patterned Lithium Niobate, Cong Deng, Joseph W. Haus, Andrew Sarangan, Aziz Mahfoud, Concita Sibilia, Michael Scalora, Aleksei M. Zheltikov
Enhanced Cerenkov Second-Harmonic Generation In Patterned Lithium Niobate, Cong Deng, Joseph W. Haus, Andrew Sarangan, Aziz Mahfoud, Concita Sibilia, Michael Scalora, Aleksei M. Zheltikov
Electro-Optics and Photonics Faculty Publications
We present experimental results of second harmonic generation enhancement through the resonance of the band edge in a photonic crystal based on lithium niobate. Proton exchange technique was used to fabricate a waveguide near the surface of the lithium niobate substrate. The photonic crystal structure over the waveguide was made by UV laser interferometry. Subsequently experiments were designed to quantify the Cerenkov second-harmonic generation (CSHG) radiated into the substrate. The SHG radiated inside the waveguides was also experimentally investigated. In our experiments, the second guided mode of the waveguide was tuned to the band edge resonance to enhance the second …
Impact Of Dietary Carotenoid Deprivation On Macular Pigment And Serum Concentrations Of Lutein And Zeaxanthin, James Loughman, John Nolan, Stephan Beatty
Impact Of Dietary Carotenoid Deprivation On Macular Pigment And Serum Concentrations Of Lutein And Zeaxanthin, James Loughman, John Nolan, Stephan Beatty
Articles
No abstract provided.
Holographic Recording In Nanoparticle-Doped Photopolymer, Izabela Naydenova, Hosam Sherif, Svetlana Mintova, Suzanne Martin, Vincent Toal
Holographic Recording In Nanoparticle-Doped Photopolymer, Izabela Naydenova, Hosam Sherif, Svetlana Mintova, Suzanne Martin, Vincent Toal
Conference Papers
A nanoparticle-doped acrylic photopolymer is characterised as a material for holographic recording. The influence of nanoparticles on the photopolymer dynamic range, dynamics of recording, temporal stability and mechanical stability in terms of shrinkage has been studied. The dynamics of recording and the temporal stability are investigated by real time monitoring of the build up of diffraction gratings of spatial frequencies of 200 to 2000 l/mm. The shrinkage has been characterised by recording slanted transmission gratings and observation of the change in the Bragg angle.
Replay At Optical Communications Wavelengths Of Holographic Gratings Recorded In The Visible, Vincent Toal, Maurice Whelan, Alberto Volcan, Izabela Naydenova, Suzanne Martin
Replay At Optical Communications Wavelengths Of Holographic Gratings Recorded In The Visible, Vincent Toal, Maurice Whelan, Alberto Volcan, Izabela Naydenova, Suzanne Martin
Conference Papers
In this paper we report on holographic diffraction gratings recorded at visible light wavelength, which can be probed at telecommunication wavelengths. The recording material is an easily prepared, self-processing photopolymer, all of whose components are water soluble. Transmission gratings of various types, namely unslanted, slanted, totally internally reflecting and Bragg gratings were all fabricated. Diffraction efficiencies at telecommunications wavelengths compare favourably with those obtained in visible light.
Comparison Of Three Electronic Speckle Pattern Shearing Interferometers Using Photopolymer Holographic Optical Elements., Emilia Mihaylova, Izabela Naydenova, Vincent Toal, Suzanne Martin
Comparison Of Three Electronic Speckle Pattern Shearing Interferometers Using Photopolymer Holographic Optical Elements., Emilia Mihaylova, Izabela Naydenova, Vincent Toal, Suzanne Martin
Conference Papers
Three electronic speckle pattern shearing interferometers (ESPSI) using photopolymer holographic gratings to produce the sheared image are presented. In the first ESPSI system two holographic gratings are used. The gratings are placed between the object and an imaging lens in front of the CCD camera. In the second ESPSI system one grating is used in combination with a sheet of ground glass. The sheared images on the ground glass are further imaged onto a CCD camera. In the third ESPSI system only one grating is used - it is placed in front of the object. The image and the sheared …