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Full-Text Articles in Physics

Signal Processing Algorithms For Doppler Lidar Sensors, Samantha Grubb May 2024

Signal Processing Algorithms For Doppler Lidar Sensors, Samantha Grubb

Physics and Astronomy Honors Papers

Light detection and ranging (LiDAR) is a remote sensing technology that obtains relative distance and velocity measurements between a sensor and a defined target by using light transmitted and received from the target. FMCW Doppler LiDAR, a particular variant of LiDAR, functions by analyzing the frequency shift in the reflected light to determine the target's range and velocity. This technology plays a crucial role across various sectors including defense, aerospace, and automotive. This paper presents signal processing algorithms designed to optimize data obtained from Doppler LiDAR sensors. By applying various window functions to time domain data, the Signal-to-Noise Ratio (SNR) …


Optical Fiber Tip Micro Anemometer, Jeremiah C. Williams, Hengky Chandrahalim Apr 2023

Optical Fiber Tip Micro Anemometer, Jeremiah C. Williams, Hengky Chandrahalim

AFIT Patents

A passive microscopic flow sensor includes a three-dimensional microscopic optical structure formed on a cleaved tip of an optical fiber. The three-dimensional microscopic optical structure includes a post attached off-center to and extending longitudinally from the cleaved tip of the optical fiber. A rotor of the three-dimensional microscopic optical structure is received for rotation on the post. The rotor has more than one blade. Each blade has a reflective undersurface that reflects a light signal back through the optical fiber when center aligned with the optical fiber, the blades of the rotor shaped to rotate at a rate related to …


Design Of Smart Trashcan, Haoran Song Apr 2021

Design Of Smart Trashcan, Haoran Song

Senior Theses

A smart trashcan has been designed which can bring convenience to people for throwing their garbage away during the COVID-19 pandemic. A prototype is made from cardboard to demonstrate its function. This trashcan can sense people who are coming and leaving, and it can open and close automatically. The trashcan is powered by solar energy. A solar panel is mounted on top of the trashcan supporter. This design is specifically for use in China.


Magnetic Field Sensors For Detection Of Trapped Flux In Superconducting Radio Frequency Cavities, Ishwari Prasad Parajuli, Gianluigi Ciovati, Jean R. Delayen Jan 2021

Magnetic Field Sensors For Detection Of Trapped Flux In Superconducting Radio Frequency Cavities, Ishwari Prasad Parajuli, Gianluigi Ciovati, Jean R. Delayen

Physics Faculty Publications

Superconducting radio frequency (SRF) cavities are fundamental building blocks of modern particle accelerators. They operate at liquid helium temperatures (2–4 K) to achieve very high quality factors (1010–1011). Trapping of magnetic flux within the superconductor is a significant contribution to the residual RF losses, which limit the achievable quality factor. Suitable diagnostic tools are in high demand to understand the mechanisms of flux trapping in technical superconductors, and the fundamental components of such diagnostic tools are magnetic field sensors. We have studied the performance of commercially available Hall probes, anisotropic magnetoresistive sensors, and flux-gate magnetometers with …


Atmospheric Measurements With Unmanned Aerial Systems (Uas), Marcelo I. Guzman Nov 2020

Atmospheric Measurements With Unmanned Aerial Systems (Uas), Marcelo I. Guzman

Chemistry Faculty Publications

This Special Issue provides the first literature collection focused on the development and implementation of unmanned aircraft systems (UAS) and their integration with sensors for atmospheric measurements on Earth. The research covered in the Special Issue combines chemical, physical, and meteorological measurements performed in field campaigns as well as conceptual and laboratory work. Useful examples for the development of platforms and autonomous systems for environmental studies are provided, which demonstrate how careful the operation of sensors aboard UAS must be to gather information for remote sensing in the atmosphere. The work serves as a key collection of articles to introduce …


Lysenin Channels As Sensors For Ions And Molecules, Andrew Bogard, Gamid Abatchev, Zoe Hutchinson, Jason Ward, Pangaea W. Finn, Fulton Mckinney, Daniel Fologea Nov 2020

Lysenin Channels As Sensors For Ions And Molecules, Andrew Bogard, Gamid Abatchev, Zoe Hutchinson, Jason Ward, Pangaea W. Finn, Fulton Mckinney, Daniel Fologea

Physics Faculty Publications and Presentations

Lysenin is a pore-forming protein extracted from the earthworm Eisenia fetida, which inserts large conductance pores in artificial and natural lipid membranes containing sphingomyelin. Its cytolytic and hemolytic activity is rather indicative of a pore-forming toxin; however, lysenin channels present intricate regulatory features manifested as a reduction in conductance upon exposure to multivalent ions. Lysenin pores also present a large unobstructed channel, which enables the translocation of analytes, such as short DNA and peptide molecules, driven by electrochemical gradients. These important features of lysenin channels provide opportunities for using them as sensors for a large variety of applications. In …


Synthesis Of Graphene Using Plasma Etching And Atmospheric Pressure Annealing: Process And Sensor Development, Andrew Robert Graves Jan 2020

Synthesis Of Graphene Using Plasma Etching And Atmospheric Pressure Annealing: Process And Sensor Development, Andrew Robert Graves

Graduate Theses, Dissertations, and Problem Reports

Having been theorized in 1947, it was not until 2004 that graphene was first isolated. In the years since its isolation, graphene has been the subject of intense, world-wide study due to its incredibly diverse array of useful properties. Even though many billions of dollars have been spent on its development, graphene has yet to break out of the laboratory and penetrate mainstream industrial applications markets. This is because graphene faces a ‘grand challenge.’ Simply put, there is currently no method of manufacturing high-quality graphene on the industrial scale. This grand challenge looms particularly large for electronic applications where the …


Odx: A Fitness Tracker-Based Device For Continuous Bacterial Growth Monitoring, Venkata V.B. Yallapragada, Uday Gowda, David Wong, Liam O'Faolain, Mark Tangney, Ganga C.R. Devarapu Sep 2019

Odx: A Fitness Tracker-Based Device For Continuous Bacterial Growth Monitoring, Venkata V.B. Yallapragada, Uday Gowda, David Wong, Liam O'Faolain, Mark Tangney, Ganga C.R. Devarapu

Cappa Publications

Continuous monitoring of bacterial growth in aqueous media is a crucial process in academic research as well as in the biotechnology industry. Bacterial growth is usually monitored by measuring the optical density of bacteria in liquid media, using benchtop spectrophotometers. Due to the large form factor of the existing spectrophotometers, they cannot be used for live monitoring of the bacteria inside bacterial incubation chambers. Additionally, the use of benchtop spectrometers for continuous monitoring requires multiple samplings and is labour intensive. To overcome these challenges, we have developed an optical density measuring device (ODX) by modifying a generic fitness tracker. The …


Merging Parallel-Plate And Levitation Actuators To Enable Linearity And Tunability In Electrostatic Mems, Mark Pallay, Ronald N. Miles, Shahrzad Towfighian Jul 2019

Merging Parallel-Plate And Levitation Actuators To Enable Linearity And Tunability In Electrostatic Mems, Mark Pallay, Ronald N. Miles, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

In this study, a linear electrostatic MEMS actuator is introduced. The system consists of a MEMS cantilever beam with combined parallel-plate and electrostatic levitation forces. By using these two forcing methods simultaneously, the static response and natural frequency can be made to vary linearly with the voltage. The static response shows a linear increase of 90 nm/V and is maintained for more than 12μm of the tip displacement. The natural frequency shows a linear increase of 16 Hz/V and is maintained throughout a 2.9 kHz shift in the natural frequency. This wide range of linear displacement and frequency tunability is …


An Integration Setup If The In-Situ Mass And Spectroscopic Analysis For Volatile Liquids Or Solids, Kolton K. Jones Apr 2018

An Integration Setup If The In-Situ Mass And Spectroscopic Analysis For Volatile Liquids Or Solids, Kolton K. Jones

Masters Theses & Specialist Projects

To help address the growing need for more and better sensors, an attempt was made to produce an in-situ mass and spectroscopic analysis of liquid and solid samples, to characterize samples and sensors. Spectroscopic analysis consisted of Raman and FTIR where mass measurements were carried out. The sample or sensor’s holder would allow for spectroscopic analysis as well as expose the sample to high temperatures and various chemicals. While Raman and FTIR were successful in producing reliable and consistent data, the constructed watt balance was not. This failure was a result of eliminate vibrational noise.


Self-Processing Photopolymer Materials For Versatile Design And Fabrication Of Holographic Sensors And Interactive Holograms, Dervil Cody, Sabad-E Gul, Tatsiana Mikulchyk, Muhammad Irfan, Anastasia Kharchenko, Kamila Goldyn, Suzanne Martin, Svetlana Mintova, John Cassidy, Izabela Naydenova Jan 2018

Self-Processing Photopolymer Materials For Versatile Design And Fabrication Of Holographic Sensors And Interactive Holograms, Dervil Cody, Sabad-E Gul, Tatsiana Mikulchyk, Muhammad Irfan, Anastasia Kharchenko, Kamila Goldyn, Suzanne Martin, Svetlana Mintova, John Cassidy, Izabela Naydenova

Articles

The aim of this paper is to discuss the benefits as well as the limitations of utilizing photopolymer materials in the design of holograms that are responsive to changes in their environment, such as changes in the concentration of a specific substance, temperature, and pressure. Three different case studies are presented, including both surface and volume phase holograms, in order to demonstrate the flexibility in the approach of utilizing holographic photopolymers for the design of sensors and interactive optical devices. First, a functionalized surface relief hologram is demonstrated to operate as an optical sensor for the detection of metal ions …


Theoretical Modeling And Design Of Photonic Structures In Zeolite Nanocomposites For Gas Sensing. Part Ii: Volume Gratings, Dervil Cody, Izabela Naydenova Jan 2018

Theoretical Modeling And Design Of Photonic Structures In Zeolite Nanocomposites For Gas Sensing. Part Ii: Volume Gratings, Dervil Cody, Izabela Naydenova

Articles

The suitability of holographic structures fabricated in zeolite nanoparticle-polymer composite materials for gas sensing applications has been investigated. Theoretical modelling of the sensor response (i.e. change in hologram readout due to a change in refractive index modulation or thickness as a result of gas adsorption) of different sensor designs was carried out using Raman-Nath theory and Kogelnik’s Coupled Wave Theory. The influence of a range of parameters on the sensitivity of holographically-recorded surface and volume photonic structures has been studied, namely hologram geometry, hologram thickness and spatial frequency, reconstruction wavelength, and zeolite nanoparticle refractive index. From this, the optimum fabrication …


Robust, Bridge-Less Ion-Selective Electrodes With Significantly Reduced Need For Pre- And Post-Application Handling, Benjamin Schazmann, S. Demey, Z. Waqar Ali, M-S Plissart, E. Brennan, A. Radu Jan 2018

Robust, Bridge-Less Ion-Selective Electrodes With Significantly Reduced Need For Pre- And Post-Application Handling, Benjamin Schazmann, S. Demey, Z. Waqar Ali, M-S Plissart, E. Brennan, A. Radu

Articles

We are demonstrating robust, single-layer ion-selective electrode (ISE) utilizing simple Ag/AgCl electrode as solid support without the need for intermediate polymer layer. We have created and chemically linked a family of imidazolium ionic liquids (ILs) with poly (vinyl chloride) (PVC) using click chemistry, resulting in hybrid materials with tunable characteristics. The resultant material inherently contains chloride ion thus offering the ability to stabilize interfacial potential. This allowed us to construct very simple, single-layer membranes with significantly reduced need for conditioning as an added bonus compared to traditional sensors. Chemical immobilization of ISE membrane components also led to extended lifetime as …


Magnetic Sensing Potential Of Fe3o4 Nanocubes Exceeds That Of Fe3o4 Nanospheres, Arati G. Kolhatkar, Yi-Ting Chen, Pawilai Chinwangso, Ivan Nekrashevich, Gamage C. Dannangoda, Ankit Singh, Andrew C. Jamison, Oussama Zenasni, Irene A. Rusakova, Karen S. Martirosyan Nov 2017

Magnetic Sensing Potential Of Fe3o4 Nanocubes Exceeds That Of Fe3o4 Nanospheres, Arati G. Kolhatkar, Yi-Ting Chen, Pawilai Chinwangso, Ivan Nekrashevich, Gamage C. Dannangoda, Ankit Singh, Andrew C. Jamison, Oussama Zenasni, Irene A. Rusakova, Karen S. Martirosyan

Physics and Astronomy Faculty Publications and Presentations

This paper highlights the relation between the shape of iron oxide (Fe3O4) particles and their magnetic sensing ability. We synthesized Fe3O4 nanocubes and nanospheres having tunable sizes via solvothermal and thermal decomposition synthesis reactions, respectively, to obtain samples in which the volumes and body diagonals/diameters were equivalent. Vibrating sample magnetometry (VSM) data showed that the saturation magnetization (Ms) and coercivity of 100–225 nm cubic magnetic nanoparticles (MNPs) were, respectively, 1.4–3.0 and 1.1–8.4 times those of spherical MNPs on a same-volume and same-body diagonal/diameter basis. The Curie temperature for the cubic Fe3O4 MNPs for each size was also higher …


N-Isopropylacrylamide-Based Photopolymer For Holographic Recording Of Thermosensitive Transmission And Reflection Grating, Tatsiana Mikulchyk, Suzanne Martin, Izabela Naydenova Jan 2017

N-Isopropylacrylamide-Based Photopolymer For Holographic Recording Of Thermosensitive Transmission And Reflection Grating, Tatsiana Mikulchyk, Suzanne Martin, Izabela Naydenova

Articles

In recent years, functionalized photopolymer systems capable of holographic recording are in great demand due to their potential use in the development of holographic sensors. This work presents a newly developed Nisopropylacrylamide(NIPA)-based photopolymer for holographic recording in reflection and transmission modes. The optimized composition of the material is found to reach refractive index modulation of up to 5  10-3 and 1.6  10-3 after recording in transmission and reflection mode, respectively. In addition to fulfilling the requirements for holographic recording materials, the NIPA-based photopolymer is sensitive to temperature and has lower toxicity than acrylamide-based photopolymers. Possible application of the …


Investigation Of A Novel Temperature-Sensing Mechanism Based On Strain-Induced Optical Path-Length Difference In A Multicore Optical Fiber, Belkis Gökbulut, Sema Güvenç, Mehmet Naci̇ İnci̇ Jan 2017

Investigation Of A Novel Temperature-Sensing Mechanism Based On Strain-Induced Optical Path-Length Difference In A Multicore Optical Fiber, Belkis Gökbulut, Sema Güvenç, Mehmet Naci̇ İnci̇

Turkish Journal of Physics

A four-core optical fiber is employed to investigate a novel temperature-sensing mechanism, which is based on the strain-induced optical path-length difference between the fiber core pairs. A short segment of a four-core fiber is wound around a solid stainless steel cylinder to form a tight circular loop, which is exposed to temperatures of up to 100 $^{\circ}$C. Temperature-induced radial expansion of the stainless steel cylinder causes a shear strain in the fiber and introduces an optical path-length difference between the fiber core pairs. This results in a total phase shift of about 20.40 $\pm $ 0.29 rad in the interference …


Zirconium Diboride, Hexagonal Boron Nitride, And Amorphous Alumina Thin Films For High Temperature Applications, David Murdock Stewart Dec 2016

Zirconium Diboride, Hexagonal Boron Nitride, And Amorphous Alumina Thin Films For High Temperature Applications, David Murdock Stewart

Electronic Theses and Dissertations

The use of microelectronic sensors and actuators in harsh, high temperature environments, such as power plants, turbine engines, and industrial manufacturing, could greatly improve the safety, reliability, and energy efficiency of these processes. The primary challenge in implementing this technology is the breakdown and degradation of thin films used in fabricating these devices when exposed to high temperatures >800 °C and oxidizing atmospheres. Zirconium diboride, hexagonal boron nitride, and amorphous alumina are candidate materials for use as thin film sensor components due to their high melting temperatures and stable phases. Zirconium diboride thin films have metallic-like electrical conductivity and remain …


Fabrication And Characterization Of Graphite Oxide Based Field Effect Transistors For Non­ Enzymatic Glucose-Sensor Application, Khadija Said Rahman Nov 2016

Fabrication And Characterization Of Graphite Oxide Based Field Effect Transistors For Non­ Enzymatic Glucose-Sensor Application, Khadija Said Rahman

Theses

Graphite-oxide based metal–oxide–semiconductor field-effect transistors (MOSFETs) were fabricated and used as glucose sensor. Herein, graphite-oxide was assembled between two planer electrical electrodes. The sensitivity of the sensor has been enhanced by adding copper (Cu) or silver (Ag) nanoparticles. The nanoparticles were produced by sputtering and inert gas condensation inside an ultra-high vacuum compatible system, and they were self-assembled on the graphite-oxide. The sensitivity of the sensor was increased by an order of magnitude when the silver nanoparticles were added. The sensitivity of each MOSFET was studied at different concentrations of non-enzymatic glucose for potential use in medical and industrial applications.


A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel Oct 2015

A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel

Terrence R Meyer

The opaque nature of many multiphase flows has long posed a significant challenge to the visualization and measurement of desired characteristics. To overcome this difficulty, X-ray imaging, both in the form of radiography and computed tomography, has been used successfully to quantify various multiphase flow phenomena. However, the relatively low temporal resolution of typical X-ray systems limit their use to moderately slow flows and time-average values. This paper discusses the development of an X-ray detection system capable of high-speed radiographic imaging that can be used to visualize multiphase flows. Details of the hardware will be given and then applied to …


Carbon Nanotube Sensors And Field Emitters, Ben Pound Dec 2014

Carbon Nanotube Sensors And Field Emitters, Ben Pound

Physics Capstone Projects

Carbon nanotube (CNT) forests are arrays of free-standing CNTs, as seen in Fig. 1a. The goal of this project was to deposit 1,5-diaminonaphthalene (DAN) evenly on each CNT. The motivation is that CNTs cannot effectively participate in chemical reactions by themselves. However, DAN can bind to the CNT surface in such a way that it can participate in chemical reactions while staying on the CNT side wall1. If DAN could be coated evenly on the CNTs throughout the forest, it could make a very sensitive biological sensor. A sensor is only as good as the number of detection …


A Solution-Based Temperature Sensor Using The Organic Compound Cutspc, Shahino Mah Abdullah Jun 2014

A Solution-Based Temperature Sensor Using The Organic Compound Cutspc, Shahino Mah Abdullah

Shahino Mah Abdullah

An electrochemical cell using an organic compound, copper (II) phthalocyanine-tetrasulfonic acid tetrasodium salt (CuTsPc,) has been fabricated and investigated as a solution-based temperature sensor. The capacitance and resistance of the ITO/CuTsPc solution/ITO chemical cell has been characterized as a function of temperature in the temperature range of 25–80 °C. A linear response with minimal hysteresis is observed. The fabricated temperature sensor has shown high consistency and sensitive response towards a specific range of temperature values.


Microfiber Coupler Based Label-Free Immunosensor, Lin Bo, Christy Charlton O'Mahony, Yuliya Semenova, Niamh Gilmartin, Pengfei Wang, Gerald Farrell Apr 2014

Microfiber Coupler Based Label-Free Immunosensor, Lin Bo, Christy Charlton O'Mahony, Yuliya Semenova, Niamh Gilmartin, Pengfei Wang, Gerald Farrell

Articles

Optical microfibers and related structures which incorporate large evanescent field and minimal size offer new opportunities for biosensing applications. In this paper we report the development of an immunosensor based on a tapered microfiber coupler embedded in a low refractive index polymer. Biomolecules adsorbed on the microfiber coupler surface modify the surrounding refractive index. By immobilizing antigens on the surface of the sensing area, the microfiber coupler was able to operate as a label-free immunosensor to detect specific antibodies. We experimentally demonstrated for the first time the sensing ability of this sensor using a fibrinogen antigen-antibody pair. By monitoring the …


Gan Nanostructuring For The Fabrication Of Thin Membranes And Emerging Applications, Ion Tiginyanu, Veaceslav Ursaki Jan 2014

Gan Nanostructuring For The Fabrication Of Thin Membranes And Emerging Applications, Ion Tiginyanu, Veaceslav Ursaki

Turkish Journal of Physics

We present a review of technological methods developed in recent years for the purpose of gallium nitride nanostructuring, with the main focus on fabrication of thin GaN membranes. In particular, we report on traditional methods of wet etching undercutting for membrane manufacturing, technologies applied for the fabrication of photonic crystal structures based on GaN nanomembranes, double side processing, and surface charge lithography. Prospects of membrane applications in photonic devices, sensors, and microoptoelectromechanical and nanoelectromechanical systems are discussed, taking into account the advantageous piezoelectric, optical, and mechanical properties of GaN and related III-V nitride materials.


A Lateral Field Excited Thin Film Bulk Acoustic Wave Sensor, Michael R. Fitzgerald Aug 2013

A Lateral Field Excited Thin Film Bulk Acoustic Wave Sensor, Michael R. Fitzgerald

Honors College

Medical and environmental needs have served as a catalyst for the development of sensors that can probe the molecular level and below. This study addresses the practicality of highly sensitive aluminum nitride (AlN) thin film bulk acoustic wave resonators (FBARs) as sensors from theoretical and experimental points of view. Theoretically, COMSOL Multiphysics simulations predict that lateral field excitation of AlN produces an electric field perpendicular to the c-axis, with the electrical energy density being concentrated in the active area of the sensor. An analysis of the piezoelectrically stiffened Christoffel equation shows that the shear mode can be excited by an …


Why A 15 Minute Biological Detection System?, Doug Lewis Jul 2013

Why A 15 Minute Biological Detection System?, Doug Lewis

Faculty Publications

The biological defense community needs to take a hard look at the requirements and assumptions we use to develop our biological sensors. Today the point sensors currently deployed or in development can offer at best “near real time” detection. This translates into approximately 10-20 minutes from the time an agent passes over the device until an alarm is issued. Why are we working to develop detection hardware which in reality contributes little to no advantage to an operational environment? Should the DOD resist fielding (in the near term) “near real time” detection systems, and instead field slower (but much more …


Modeling A Sensor To Improve Its Efficacy, Nabin K. Malakar, Daniil Gladkov, Kevin H. Knuth May 2013

Modeling A Sensor To Improve Its Efficacy, Nabin K. Malakar, Daniil Gladkov, Kevin H. Knuth

Physics Faculty Scholarship

Robots rely on sensors to provide them with information about their surroundings. However, high-quality sensors can be extremely expensive and cost-prohibitive. Thus many robotic systems must make due with lower-quality sensors. Here we demonstrate via a case study how modeling a sensor can improve its efficacy when employed within a Bayesian inferential framework. As a test bed we employ a robotic arm that is designed to autonomously take its own measurements using an inexpensive LEGO light sensor to estimate the position and radius of a white circle on a black field. The light sensor integrates the light arriving from a …


Bulk Heterojunction Photodiode: To Detect The Whole Visible Spectrum, Shahino Mah Abdullah Feb 2013

Bulk Heterojunction Photodiode: To Detect The Whole Visible Spectrum, Shahino Mah Abdullah

Shahino Mah Abdullah

In this paper, we report an organic bulk heterojunction photo-sensor that has been fabricated by using a composite of a polymer material poly(3-hexylthiophene-2,5-diyl) (P3HT) and a dye material vanadyl-phthalocyanine (VOPcPhO). The UV–Vis spectrum shows that this composite exhibits a broad absorption over the whole visible range. The photoluminescence (PL) spectra of P3HT and VOPcPhO blend have been studied to optimize the ratio of P3HT and VOPcPhO. The photo-sensitivity has been investigated under different applied voltages in reverse direction. The photoconductivity sensitivity value has been calculated as 5.65 × 102 Sm/W. The photo-responsivity of the sensor has been investigated under 100 …


Research On Holographic Sensors And Novel Photopolymers At The Centre For Industrial And Egnineering Optics, Emilia Mihaylova, Dervil Cody, Izabela Naydenova, Suzanne Martin, Vincent Toal Jan 2013

Research On Holographic Sensors And Novel Photopolymers At The Centre For Industrial And Egnineering Optics, Emilia Mihaylova, Dervil Cody, Izabela Naydenova, Suzanne Martin, Vincent Toal

Books/Book Chapters

The recent resurgence of interest in photopolymers for commercial holograms is a strong incentive for development of photopolymers that are as environmentally friendly as possible. Photopolymer materials consist of a light-sensitive film which is exposed during production to form the hologram, thereby offering versatility well beyond that of current security holograms, which are mass produced from a master using a foil stamping processes.


Temperature-Sensitive Chemical Cell Based On Nickel (Ii) Phthalocyanine-Tetrasulfonic Acid Tetrasodium Salt, Shahino Mah Abdullah Mar 2012

Temperature-Sensitive Chemical Cell Based On Nickel (Ii) Phthalocyanine-Tetrasulfonic Acid Tetrasodium Salt, Shahino Mah Abdullah

Shahino Mah Abdullah

An organic compound Nickel (II) phthalocyanine-tetrasulfonic acid tetrasodium salt (NiTSPc) has been studied as a potential material for a solution based temperature sensor. Using NiTSPc, an ITO/NiTSPc solution/ITO chemical cell has been made and characterized in the temperature range of 20–85 ◦C. This sensor works on the principle of change in the resistance and capacitance of the chemical cell caused by the temperature variation. Good response/recovery and small hysteresis have been attained. The proposed sensor is aimed to evolve towards highly sensitive organic temperature sensor in a specific temperature range.


Coupled Photonic Crystal Micro-Cavities With Ultra-Low Threshold Power For Stiumulated Raman Scattering, Qiang Liu, Zhengbiao Ouyang, Sacharia Albin Jan 2011

Coupled Photonic Crystal Micro-Cavities With Ultra-Low Threshold Power For Stiumulated Raman Scattering, Qiang Liu, Zhengbiao Ouyang, Sacharia Albin

Electrical & Computer Engineering Faculty Publications

We propose coupled cavities to realize a strong enhancement of the Raman scattering. Five sub cavities are embedded in the photonic crystals. Simulations through finite-difference time-domain (FDTD) method demonstrate that one cavity, which is used to propagate the pump beam at the optical-communication wavelength, has a Q factor as high as 1.254 × 108 and modal volume as small as 0.03μm3 (0.3192(λ/n)3). These parameters result in ultra-small threshold lasing power ~17.7nW and 2.58nW for Stokes and anti-Stokes respectively. The cavities are designed to support the required Stokes and anti-Stokes modal spacing in silicon. The proposed structure …