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Full-Text Articles in Physics

Strain-Induced Spectral Tuning Of The Whispering Gallery Modes In A Cylindrical Micro-Resonator Formed By A Polymer Optical Fiber, Vishnu Kavungal, Arun Mallik, Gerald Farrell, Qiang Wu, Yuliya Semenova Feb 2017

Strain-Induced Spectral Tuning Of The Whispering Gallery Modes In A Cylindrical Micro-Resonator Formed By A Polymer Optical Fiber, Vishnu Kavungal, Arun Mallik, Gerald Farrell, Qiang Wu, Yuliya Semenova

Articles

A mechanical strain assisted technique for spectral tuning of whispering gallery modes (WGM) in a cylindrical micro-resonator formed by a polymer optical fiber (POF) is investigated. WGMs in the POF based micro-cylinder are excited by evanescent light coupling using a tapered single mode silica fiber. WGMs observed in the transmission spectrum of the silica fiber taper have a high extinction ratio of up to 19 dB and a Q-factor of up to 2.64 × 104. The application of tensile axial strain (μɛ) in the range from 0 to 1746 μɛ (0.17 %) to the POF micro-resonator results in …


Application Of Phase Shifting Electronic Speckle Pattern Interferometry In Studies Of Photoinduced Shrinkage Of Photopolymer Layers, Mohesh Moothanchery, Viswanath Bavigadda, Manojit Pramanik, Vincent Toal, Izabela Naydenova Jan 2017

Application Of Phase Shifting Electronic Speckle Pattern Interferometry In Studies Of Photoinduced Shrinkage Of Photopolymer Layers, Mohesh Moothanchery, Viswanath Bavigadda, Manojit Pramanik, Vincent Toal, Izabela Naydenova

Articles

Photoinduced shrinkage occurring in photopolymer layers during holographic recording was determined by Phase Shifting Electronic Speckle Pattern Interferometry. Phase maps were calculated from the changes in intensity at each pixel due to the phase differences introduced between object and reference beams. Shrinkage was then obtained from the changes in phase as recording proceeded. The technique allows for whole field measurement of the dimensional changes in photopolymers during holographic recording.


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 …


Humidity And Temperature Induced Changes In The Diffraction Efficiency And The Bragg Angle Of Slanted Photopolymer-Based Holographic Gratings, Tatsiana Mikulchyk, James Walshe, Dervil Cody, Suzanne Martin, Izabela Naydenova Jan 2017

Humidity And Temperature Induced Changes In The Diffraction Efficiency And The Bragg Angle Of Slanted Photopolymer-Based Holographic Gratings, Tatsiana Mikulchyk, James Walshe, Dervil Cody, Suzanne Martin, Izabela Naydenova

Articles

This work explores the humidity and temperature response of volume phase slanted gratings recorded in photopolymers with varied chemical composition. Acrylamide and diacetone acrylamide were used as monomers and triethanolamine and N-phenylglycine were used as photoinitiators. The study demonstrates that the response of photopolymer-based holographic gratings to relative humidity (RH) and temperature (T) can be tuned by alteration of the photopolymer composition.Humidity and temperature response of the holograms has been characterized by recording Bragg selectivity curves of transmission gratings and by monitoring the position of the maximum intensity in the spectral response of reflection gratings. Investigation of the humidity response …


Compact Holographic Optical Element-Based Electronic Speckle Pattern Interferometer For Rotation And Vibration Measurements, Viswanath Bavigadda, Mohesh Moothanchery, Manojit Pramanik, Emilia Mihaylova, Vincent Toal Jan 2017

Compact Holographic Optical Element-Based Electronic Speckle Pattern Interferometer For Rotation And Vibration Measurements, Viswanath Bavigadda, Mohesh Moothanchery, Manojit Pramanik, Emilia Mihaylova, Vincent Toal

Conference Papers

An out-of-plane sensitive electronic speckle pattern interferometer (ESPI) using holographic optical elements (HOEs) for studying rotations and vibrations is presented. Phase stepping is implemented by modulating the wavelength of the laser diode in a path length imbalanced interferometer. The time average ESPI method is used for vibration measurements. Some factors influencing the measurements accuracy are reported. Some advantages and limitations of the system are discussed.


Advancing Vibrational Spectroscopy For Cellular And Sub Cellular Analysis: Raman Spectroscopy As An In Vitro Chemotherapeutic Screeening And Assessment Protocol, Zeineb Farhane Jan 2017

Advancing Vibrational Spectroscopy For Cellular And Sub Cellular Analysis: Raman Spectroscopy As An In Vitro Chemotherapeutic Screeening And Assessment Protocol, Zeineb Farhane

Doctoral

Vibrational spectroscopy, including Raman micro-spectroscopy, has attracted considerable attention over the last few years, as a powerful, non-invasive tool for clinical applications, especially in cancer diagnosis, in vivo and ex vivo. As a molecular fingerprinting technique with optical resolution, Raman micro-spectroscopy is able to monitor biochemical processes, drug uptake, efficacy and mode of action and mechanisms of interaction of chemotherapeutic drugs at a subcellular level. In vitro applications may be more strategically achievable, and can help guide drug design and discovery, and eventually evaluate To this end, different lung cell lines were used and Raman micro-spectroscopy was coupled to valuable …


Development And Characterisation Of A Bath-Based Vertical Blackbody Cavity Calibration Source For The Range −30 °C To 150 °C, Sam Boles, Igor Pušnik, Dubhaltach Mac Lochlainn, David Fleming, Izabela Naydenova, Suzanne Martin Jan 2017

Development And Characterisation Of A Bath-Based Vertical Blackbody Cavity Calibration Source For The Range −30 °C To 150 °C, Sam Boles, Igor Pušnik, Dubhaltach Mac Lochlainn, David Fleming, Izabela Naydenova, Suzanne Martin

Articles

Industrial use of Radiation Thermometers (RTs) is becoming increasingly common due to the perceived advantages and wide market availability. Blackbody Cavity Radiation Sources (BCRSs) are typically used for calibration of these instruments, and these cavities are oriented horizontally in most cases. For BCRSs based in thermal baths, this necessitates the use of custom-built baths with side openings. This paper presents a unique design of vertical bath-based BCRS that may be immersed in conventional calibration baths without modifications to the baths. The method, results, and analysis of an international comparison comparing this vertical BCRS, standard horizontal BCRSs, and a previous iteration …


Effect Of Monomer Diffusion On Photoinduced Shrinkage In Photopolymer Layers Determined By Electronic Speckle Pattern Interferometry, Mohesh Moothanchery, Manojit Pramanik, Vincent Toal, Izabela Naydenova Jan 2017

Effect Of Monomer Diffusion On Photoinduced Shrinkage In Photopolymer Layers Determined By Electronic Speckle Pattern Interferometry, Mohesh Moothanchery, Manojit Pramanik, Vincent Toal, Izabela Naydenova

Conference Papers

The aim of this study is to determine the effect of monomer diffusion on the photoinduced shrinkage profile in acrylamide based photopolymer layers during holographic recording. Using phase shifting electronic speckle pattern interferometry the displacement at each pixel in the image of the layer is measured. The complete displacement profile of the layer was obtained using phase shifting technique. We observed a reduction in shrinkage as a result of monomer diffusion from unexposed regions of holographic exposure. As a result of diffusion the maximum shrinkage was reduced by 26 % from 7.18μm to 5.28μm in a photopolymer layer of thickness160 …