Optics Commons^™

Digital Holography And Applications In Microscopic Interferometry, Cody Jenkins

Physics

In this project I demonstrate recording holograms using an electronic camera as the photosensitive element and subsequent numerical reconstruction in a digital computer. The technique is employed to show extended depth of field imaging as well as phase contrast imaging via microscopic interferometry.

Sensitive Fluorescence Detection Using A Camera From The Gaming Industry, Brian L. Van Hoozen Jr.

Lawrence University Honors Projects

The detection limit for fluorescence imaging has been improved by more than two orders of magnitude by a modulation technique that minimizes the influence of noise. Since most noise sources have a 1/f dependence, higher modulation frequencies result in less noise in the detected signal. Typical cameras used for imaging have frame rates of 50 or 100 hertz which is too low for substantial noise reduction. However, new time-of-flight cameras developed for the gaming industry have modulation frequencies of up to 20 MHz, allowing for a substantial reduction in noise in the detected signal. In this study, the improved detection …

Gaussian Beam Steering On A Target Plane Via High Speed Orthogonal Mirror-Mounted Galvanometers, Keith Gresiak

Physics

No abstract provided.

Day/Night Band Imager For A Cubesat, Eric Stanton

Electrical Engineering

Day/Night Band (DNB) earth sensing and meteorological systems like the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) provide visible wavelength imagery 24 hours a day that is used primarily for cloud imaging in support of weather forecasting. This paper describes a compact push-broom imager that meets low light imaging requirements for DMSP OLS and the NOAA/NASA Joint Polar Satellite System (JPSS) as documented in the Integrated Operational Requirements Document [1] (IORD) including the imager design, system level concepts of operation for data collection, radiometric and spatial calibration, and data transmission to Earth. This small, lightweight imager complies with …

Point-Spread Function Assessment Of Sg-Dbr Based Swept Source For Oct Imaging, David Wilkey Gilbert

Master's Theses

Swept Source Optical Coherence Tomography (SS-OCT) is a medical imaging technique that requires high repetition rate, widely-tunable coherent laser sources. Sampled grating distributed Bragg reflector (SG-DBR) lasers are proven in telecom applications and are expected to fulfill the requirements for SS-OCT at a significantly lower cost than alternative solutions.

Constructed entirely on a semiconductor substrate, SG-DBR lasers require four synchronized waveforms to modulate the output wavelength and intensity. Because of this unique tuning mechanism, there are a number of systematic and noise sources that can affect the quality of the OCT point-spread function (PSF). Based on these noise sources, software …

Diacetone Acrylamide-Based Non-Toxic Holographic Photopolymer, Dervil Cody, Izabela Naydenova, Emilia Mihaylova

Conference Papers

A new low-toxicity diacetone acrylamide-based photopolymer is developed and characterized. The environmentally-compatible photopolymer has been modified with the inclusion of glycerol. The incorporation of glycerol results in a uniform maximum refractive index modulation for recording intensities in the range of 1-20 mW/cm². This may be attributed to glycerol’s nature as a plasticizer, which allows for faster diffusion of un-reacted monomer within the grating during holographic recording. An optimum recording intensity of 0.5 mW/cm² is observed for exposure energies of 20-60 mW/cm². The modified photopolymer achieves a refractive index modulation of 2.2x10^-3, with diffraction …

Building And Characterization Of Laser Diodes As Well As System Design Of A Dual Wavelength Fabry-Perot Interferometer, Nicholas Czapla

Physics

No abstract provided.

Real Time Shrinkage Studies In Photopolymer Films Using Holographic Interferometry, Mohesh Moothanchery, Izabela Naydenova, Viswanath Bavigadda, Suzanne Martin, Vincent Toal

Conference Papers

Polymerisation induced shrinkage is one of the main reasons why photopolymer materials are not more widely used for holographic applications. The aim of this study is to evaluate the shrinkage in an acrylamide photopolymer layer during holographic recording using holographic interferometry. Shrinkage in photopolymer layers can be measured by real time capture of holographic interferograms during holographic recording. Interferograms were captured using a CMOS camera at regular intervals. The optical path length change and hence the shrinkage were determined from the captured fringe patterns. It was observed that the photopolymer layer shrinkage is in the order of 3.5%.

Dynamical Model Of Harmonic Generation In Centrosymmetric Semiconductors At Visible And Uv Wavelengths, Michael Scalora, Maria Antonietta Vincenti, Domenico De Ceglia, N. Akozbek, Vito Roppo, M. J. Bloemer, Joseph W. Haus

Electrical and Computer Engineering Faculty Publications

We study second and third harmonic generation in centrosymmetric semiconductors at visible and UV wavelengths in bulk and cavity environments. Second harmonic generation is due to a combination of spatial symmetry breaking, the magnetic portion of the Lorentz force, and quadrupolar contributions from inner core electrons. The material is assumed to have a nonzero, third-order nonlinearity that gives rise to most of the third harmonic signal. Using the parameters of bulk silicon we predict that cavity environments modify the dependence of second harmonic generation on incident angle, while improving third harmonic conversion efficiency by several orders of magnitude relative to …

Modelling Two-Dimensional Photopolymer Patterns Produced With Multiple-Beam Holography, Dana Mackey, Tsvetanka Babeva, Izabela Naydenova, Vincent Toal

Conference papers

Periodic structures referred to as photonic crystals attract considerable interest due to their potential applications in areas such as nanotechnology, photonics, plasmonics, etc. Among various techniques used for their fabrication, multiple-beam holography is a promising method enabling defect-free structures to be produced in a single step over large areas.

In this paper we use a mathematical model describing photopolymerisation to simulate two-dimensional structures produced by the interference pattern of three noncoplanar beams. The holographic recording of different lattices is studied by variation of certain parameters such as beam wave vectors, time and intensity of illumination.

Bounded Phase Phenomena In The Optically Injected Laser, Bryan Kelleher, David Goulding, B. Baselga Pascual, Stephen P. Hegarty, Guillaume Huyet

Cappa Publications

Two routes to phase-locking in the optically injected laser system are investigated both involving limit cycles where the phase of the slave laser is unlocked but is nevertheless bounded. We use an experimental phase-resolving technique to unambiguously demonstrate the phenomenon via explicit phasors for the slave laser electric field. Theoretical considerations show that for locking mechanisms involving Hopf bifurcations, such limit cycles of bounded phase are generic. For weakly damped devices, such as quantum well lasers, this can involve an excited resonance at the relaxation oscillation frequency. For highly damped devices there is no such excitation but the bounded phase …

Observations With The Most Sensitive Rayleigh-Scatter Lidar, Leda Sox, Vincent B. Wickwar, Joshua P. Herron, Marcus J. Bingham

Graduate Student Posters

The mesosphere is the most unexplored region of the atmosphere. Its altitude range of 50-85 km lies in between the reaches of data collecting instruments like weather balloons and satellites. For this reason, remote sensing systems, such as lidar, which are able to employ ground-based instruments to make extensive measurements in this difficult to detect region. The Rayleigh-scatter lidar at USU is currently being redeveloped to be the most powerful and sensitive of its kind. This type of lidar exploits light and particle interactions, like those that account for the blue color of the sky, to make relative density and …

Quantum Mutual Information Capacity For High-Dimensional Entangled States, P. Ben Dixon, Gregory A. Howland, James Schneeloch, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

High-dimensional Hilbert spaces used for quantum communication channels offer the possibility of large data transmission capabilities. We propose a method of characterizing the channel capacity of an entangled photonic state in high-dimensional position and momentum bases. We use this method to measure the channel capacity of a parametric down-conversion state by measuring in up to 576 dimensions per detector. We achieve a channel capacity over 7  bits/photon in either the position or momentum basis. Furthermore, we provide a correspondingly high-dimensional separability bound that suggests that the channel performance cannot be replicated classically.

Information Encryption And Retrieval In Mid-Rf Range Using Acousto-Optic Chaos, Monish Ranjan Chatterjee, Abhinay Kundur

Electrical and Computer Engineering Faculty Publications

In recent work, low-frequency AC signal encryption, decryption and retrieval using system-parameter based keys at the receiver stage of an acousto-optic (A-O) Bragg cell under first-order feedback have been demonstrated [1,2]. The corresponding nonlinear dynamics have also been investigated using the Lyapunov exponent and the so-called bifurcation maps [3]. The results were essentially restricted to A-O chaos around 10 KHz, and (baseband) signal bandwidths in the 1-4 KHz range. The results have generally been satisfactory, and parameter tolerances (prior to severe signal distortion at the output) in the ±5% - ±10% range have been obtained.

Periodic AC waveforms, and a …

Mid-Infrared Upconversion Spectroscopy Based On A Yb:Fiber Femtosecond Laser, Todd Johnson, Scott A. Diddams

Physics Faculty Publications

We present a system for molecular spectroscopy using a broadband mid-infrared laser with near-infrared detection. Difference frequency generation of a Yb:fiber femtosecond laser produced a mid-infrared (MIR) source tunable from 2100–3700 cm^-1 (2.7–4.7 μm) with average power up to 40 mW. The MIR spectrum was upconverted to near-infrared wavelengths for broadband detection using a two-dimensional dispersion imaging technique. Absorption measurements were performed over bandwidths of 240 cm^-1 (7.2 THz) with 0.048 cm^-1 (1.4 GHz) resolution, and absolute frequency scale uncertainty was better than 0.005 cm^-1 (150 MHz). The minimum detectable absorption coefficient per spectral element was …

Laser Processing Of Metals And Polymers, Senthilraja Singaravelu

Physics Theses & Dissertations

A laser offers a unique set of opportunities for precise delivery of high quality coherent energy. This energy can be tailored to alter the properties of material allowing a very flexible adjustment of the interaction that can lead to melting, vaporization, or just surface modification. Nowadays laser systems can be found in nearly all branches of research and industry for numerous applications. Sufficient evidence exists in the literature to suggest that further advancements in the field of laser material processing will rely significantly on the development of new process schemes. As a result they can be applied in various applications …

Optimization Framework For A Radio Frequency Gun Based Injector, Alicia S. Hofler

Electrical & Computer Engineering Theses & Dissertations

Linear accelerator based light sources are used to produce coherent x-ray beams with unprecedented peak intensity. In these devices, the key parameters of the photon beam such as brilliance and coherence are directly dependent on the electron beam parameters. This leads to stringent beam quality requirements for the electron beam source. Radio frequency (RF) guns are used in such light sources since they accelerate electrons to relativistic energies over a very short distance, thus minimizing the beam quality degradation due to space charge effects within the particle bunch. Designing such sources including optimization of its beam parameters is a complex …

Remote Sensing Phase Fluorimetry Using Mercury Vapor Lamp, Matthew J. Bohn, Michael A. Lundin

AFIT Patents

An efficient and portable method for remote detection of a target mineral material through frequency domain fluorimetry, a detection technique that measures the time lag between absorption and emission of photons, thereby determining the lifetime of said target mineral material. As claimed and disclosed in the present invention, mercury vapor lamps, a common source of industrial facility lighting, emit radiation that overlaps the UV/blue absorption spectrum of many fluorophores and may be used as an efficient and portable excitation source for remote frequency domain fluorimetry.

Matrix Determination Of Reflectivity Of Hidden Object Via Indirect Photography, Simon S. Ferrel

Theses and Dissertations

Indirect photography is a recently demonstrated technique which expands on the principles of dual photography and allows for the imaging of hidden objects. A camera and light source are collocated with neither having line-of-sight access to the hidden object. Light from the source, a laser, is reflected off a visible non-specular surface onto the hidden object, where it is reflected back to the initial non-specular surface and collected by the camera. This process may be repeated numerous times for various laser spot positions to yield slightly different camera images due to a variation in the illumination of the object. These …

Electrical And Optical Characterization Of Si-Ge-Sn, Merle D. Hamilton

Theses and Dissertations

The electrical characterization of boron-doped p-Si_0.08Ge_0.90Sn_0.02/p-Ge(100) and p-Si_0.112Ge_0.86Sn_0.028/n-Si(100) with various epilayer thicknesses was measured using the Hall effect. The room temperature sheet carrier concentration ranged from 1.21 x 10¹³ – 1.32 x 10¹⁶ cm^-2. The room temperature mobilities were measured to be between 166 and 717 cm²/V·s, depending on sample composition. In the low temperature regime, the mobility was mainly affected by ionized impurity scattering. In the high temperature regime, the mobility was mainly affected by …