Dr. Dervil Cody Profile

Dr. Dervil Cody

Lecturer at Technological Univ Dublin

SPIE Involvement:

Author

Area of Expertise:

holography , photopolymers , medical physics

Lecturer in the School of Physics, Clinical and Optometric Sciences, TU Dublin.

Researcher at the Centre for Industrial and Engineering Optics, TU Dublin.

Research interests include: quality assurance and calibration of medical technologies, photonic sensors, optical material development

Proceedings Article | 13 March 2024 Presentation

Development of novel hologram-based sensors for patient dosimetry in daylight photodynamic therapy (D-PDT)

Saoirse Maher, Jackie McCavana, Seán Cournane, Suzanne Martin, Dervil Cody

Proceedings Volume PC12823, PC128230A (2024) https://doi.org/10.1117/12.2689897

KEYWORDS: Dosimetry, Light absorption, Holography, Sensors, Photodynamic therapy, Holograms, Optical gratings, Optical properties, Holographic interferometry, Diffraction gratings

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Proceedings Article | 31 May 2023 Presentation + Paper

Design and fabrication of volume holographic optical couplers for a range of non-normal incidence angles

Dipanjan Chakraborty, Rosen Georgiev, Sinead Aspell, Vincent Toal, Izabela Naydenova, Dervil Cody, Suzanne Martin

Proceedings Volume 12574, 125740E (2023) https://doi.org/10.1117/12.2665596

KEYWORDS: Holographic optical elements, Diffraction, Holography, Diffraction gratings, Bragg wavelengths, Spatial frequencies, Total internal reflection, Photopolymers, Volume Bragg gratings, Diffractive optical elements, Holographic materials

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Proceedings Article | 31 May 2023 Presentation + Paper

Development of holographic optical elements for use in wound monitoring

P. Stoeva, T. Mikulchyk, B. Rogers, M. Oubaha, S. Martin, D. Cody, M. Ferrara, G. Coppola, I. Naydenova

Proceedings Volume 12574, 1257406 (2023) https://doi.org/10.1117/12.2665499

KEYWORDS: Waveguides, Holographic optical elements, Diffraction gratings, Holography, Diffraction, Wound healing, Sol gels, Sensing systems

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Proceedings Article | 30 May 2022 Presentation

Development of photosensitive sol-gel material for high refractive index modulation using thermal treatment during post exposure diffraction efficiency growth process

Brian Rogers, Tatsiana Mikulchyk, Pamela Stoeva, Dervil Cody, Mohamed Oubaha, Suzanne Martin, Izabela Naydenova

Proceedings Volume PC12151, PC1215103 (2022) https://doi.org/10.1117/12.2621202

KEYWORDS: Diffraction, Refractive index, Modulation, Sol-gels, Holograms, Glasses, Water, Volume holography, Spatial frequencies, Solar concentrators

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Proceedings Article | 30 May 2022 Presentation

Mechanism of grating formation in a fast-curing and water-resistant photopolymerisable glass

Tatsiana Mikulchyk, Brian Rogers, Pamela Stoeva, Alicja Kaworek, Mohamed Oubaha, Suzanne Martin, Dervil Cody, Izabela Naydenova

Proceedings Volume PC12151, PC1215101 (2022) https://doi.org/10.1117/12.2618100

KEYWORDS: Holographic optical elements, Glasses, Holography, Diffraction gratings, Sol-gels, Optical lithography, Diffraction, Volume holography, Solar concentrators, Refractive index

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The demand for holographic optical elements (HOEs) is continuously increasing due to their potential applications in a wide range of quickly advancing technologies. The main challenge for HOE development is in the design and preparation of holographic materials, which satisfy environmental requirements during device exploitation. Photosensitive glasses are potential candidates for the development of HOEs with improved environmental stability, mechanical stability and hardness. Recently, a novel photopolymerisable hybrid sol-gel (PHSG) for holographic recording of volume gratings with high performance has been reported. Due to its valuable combination of properties, PHSG has potential for mass-production of highly efficient and durable optical devices with long-term stable performance at different ambient conditions. Nevertheless, the mechanism of grating formation is not fully characterised and understood. To achieve control over the performance of the material and further improve its properties, systematic study is required. In this research, the mechanism of grating formation in the PHSG is investigated by analysing two main effects contributing to the refractive index modulation. The first effect is density change due to both polymerization of monomers under holographic patterning and polycondensation caused by natural aging of the sol-gel material. The second effect is diffusion of mobile species such as dye molecules induced by concentration gradients and/or distribution of small nanoparticles caused by spatially varying heat dissipation resulting from light absorption during holographic patterning. Experimental results confirn that the mechanism of grating formation in the PHSG can be defined as the creation of spatially-varying refractive index within the bulk of the material mainly due to changes in density induced by photopolymerisation and polycondensation. Diffusion processes are observed to have low impact on the grating formation. The proposed model facilitates controlled and predictable diffraction efficiency of gratings recorded on the PHSG, thereby furthering the prospect of the development of HOEs with customisable specification.

Proceedings Article | 13 April 2020 Presentation + Paper

Optimisation of the performance of holographic beam-shaping diffractive diffusers through refinement of the recording process

Cara Jones, Suzanne Martin, Sanjay Keshri, Dervil Cody, Kevin Murphy

Proceedings Volume 11367, 1136706 (2020) https://doi.org/10.1117/12.2555774

KEYWORDS: Diffusers, Holography, Speckle, Speckle pattern, Modeling, Volume holography, Diffraction, Beam shaping, Photopolymers, Diffraction gratings, Holographic optical elements

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Proceedings Article | 1 April 2020 Presentation

Investigation of nanozeolite-doped holographic structures for sensing volatile organic compounds (Conference Presentation)

Graceson Antony, Dervil Cody, Svetlana Mintova, Izabela Naydenova

Proceedings Volume 11354, 1135412 (2020) https://doi.org/10.1117/12.2554967

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Proceedings Article | 1 April 2020 Presentation

Novel fast drying and water resistant photopolymerisable glass for volume holography (Conference Presentation)

Tatsiana Mikulchyk, Mohamed Oubaha, Sabad E-Gul, Izabela Naydenova, Dervil Cody

Proceedings Volume 11367, 113670G (2020) https://doi.org/10.1117/12.2555360

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Proceedings Article | 8 May 2015 Paper

Humidity and temperature response of photopolymer-based holographic gratings

Tatsiana Mikulchyk, James Walshe, Dervil Cody, Suzanne Martin, Izabela Naydenova

Proceedings Volume 9508, 950809 (2015) https://doi.org/10.1117/12.2183782

KEYWORDS: Photopolymers, Humidity, Diffraction gratings, Diffraction, Holography, Sensors, Temperature metrology, Reflection, Refractive index, Visual optics

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Holographic sensors have significant potential in various applications ranging from in vitro diagnostics to optical security. They are capable of providing fast, real-time, reversible or irreversible, visual colorimetric or optical readouts. The main challenge in the development of holographic sensors is to improve their selectivity by functionalizing the holographic recording material and achieve a response to a specific analyte. This material should be permeable to the analyte and its properties should change under exposure to the analyte. This work explores the humidity and temperature response of volume phase gratings recorded in photopolymers containing acrylamide and diacetone acrylamide as monomers, and triethanolamine and N-phenylglycine as photoinitiators. Characterization of the humidity response of photopolymer-based gratings in the relative humidity (RH) range of 20-90 % was carried out by measuring the diffraction efficiency of slanted transmission gratings and the position of the maximum intensity in the spectral response of reflection gratings. A strong humidity dependence of the diffraction efficiency of diacetone acrylamide-based transmission gratings was observed at RH=20-90%. The humidity dependence of the spectral response of the reflection gratings showed that photopolymers containing triethanolamine are more hydrophilic than photopolymers containing N-phenylglycine. The temperature response of slanted transmission gratings was investigated in the temperature (T) range of 20–60 °C. Exposure of the photopolymer layers containing triethanolamine to elevated temperature showed that the observed Bragg angle shift was caused by layer shrinkage due to water evaporation. The application of a sealing technique allowed for the observation of the photopolymer layer swelling due to the layer’s thermal expansion. The results demonstrate an effective approach to obtaining photopolymer-based gratings with tuneable temperature and humidity sensitivity.

Proceedings Article | 5 May 2012 Paper

Diacetone acrylamide-based non-toxic holographic photopolymer

D. Cody, I. Naydenova, E. Mihaylova

Proceedings Volume 8429, 84291B (2012) https://doi.org/10.1117/12.923116

KEYWORDS: Refractive index, Modulation, Holography, Polymerization, Molecules, Diffusion, Spatial frequencies, Diffraction gratings, Lens design, Physics

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