Dr. Kevin P. Murphy Profile

Dr. Kevin P. Murphy

at FOCAS Research Institute TU Dublin

SPIE Involvement:

Author

Publications (8)

SPIE Journal Paper | 14 February 2024 Open Access

Modeling holographic optical element performance with an extended source; experimental investigation using misaligned point sources

Jorge Lasarte, Kevin Murphy, Izabela Naydenova, Jesús Atencia, Maria Victoria Collados, Suzanne Martin

JOM, Vol. 4, Issue 01, 014002, (February 2024) https://doi.org/10.1117/12.10.1117/1.JOM.4.1.014002

KEYWORDS: Holographic optical elements, Light emitting diodes, Diffraction, Lenses, Modeling, Holography, Spatial frequencies, MATLAB, Beam divergence, Zemax

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Proceedings Article | 31 May 2023 Presentation + Paper

Modelling HOE performance with an extended source: experimental investigation using misaligned point sources

Jorge Lasarte, Kevin Murphy, Izabela Naydenova, Jesús Atencia, M. Victoria Collados, Suzanne Martin

Proceedings Volume 12574, 1257405 (2023) https://doi.org/10.1117/12.2665494

KEYWORDS: Holographic optical elements, Diffraction, Light emitting diodes, Lenses, Holography, Spatial frequencies, MATLAB, Beam divergence, Zemax, Modeling

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Proceedings Article | 12 September 2021 Presentation + Paper

Direct multiplexing of low order aberration modes in a photopolymer-based holographic element for analog holographic wavefront sensing

Emma Branigan, Suzanne Martin, Matthew Sheehan, Kevin Murphy

Proceedings Volume 11860, 118600H (2021) https://doi.org/10.1117/12.2599912

KEYWORDS: Holographic optical elements, Diffraction, Holography, Wavefront sensors, Multiplexing, Near infrared, Collimation, Holograms, Analog electronics, Wavefronts

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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

Multilayer photopolymer for broad spectral range holographic optical elements (Conference Presentation)

Sanjay Keshri, Izabela Naydenova, Kevin Murphy, Suzanne Martin

Proceedings Volume 11367, 113670Q (2020) https://doi.org/10.1117/12.2556006

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Diffractive Optical Elements (DOEs) utilize diffraction at sub-micron features to re-direct and control light. Volume phase holographic materials, such as photopolymer, are advantageous for use in fabricating optical elements because the diffraction efficiency can approach 100%, the whole element can be recorded in one exposure and high diffraction and slant angles are possible. Self-developing photopolymers also facilitate mass manufacture. Holographic gratings have been developed for numerous applications including spectroscopy, solar concentration, and monochrome LEDs, however, the inherent angular and wavelength selectivity of the volume phase hologram generally restricts applications to laser systems and sources with narrow spectral ranges. Multiplexing more than one grating into a single photopolymer layer can extend the range, however, unwanted additional gratings are frequently recorded. In this paper, we discuss laminating multiple photopolymer HOEs together as a method for increasing the wavelength and angular working range of devices. This involves combining HOEs designed to produce the desired output beam for different angular and/or spectral input beams. Stacking of photopolymer layers has previously been demonstrated to increase the angular range of gratings and recently the authors produced a compound HOE with significantly broadened wavelength and angular selectivity curves by laminating two HOEs recorded sequentially at a single wavelength. However, such solutions are not easily translated to more complex elements such as lenses where the spatial frequency and grating slant angles are varying. This paper discusses laminating together two photopolymer layers sensitized for different recording wavelengths for the purpose of holographically recording a compound-element volume-HOE lens for use with a broadband LED. The angular and wavelength selectivity are characterized and the challenges and advantages of the different approaches are discussed and compared.

Proceedings Article | 15 May 2017 Presentation + Paper

Comparison of two methods for equalising the diffraction efficiency of different spatial frequency components of holographic optical elements

S. Keshri, K. Murphy, V. Toal, I. Naydenova, S. Martin

Proceedings Volume 10233, 102330X (2017) https://doi.org/10.1117/12.2265598

KEYWORDS: Refractive index, Volume holography, Modulation, Photopolymers, Collimation, Diffraction, Holographic optical elements, Spatial frequencies, Holography, Light emitting diodes, Diffraction gratings, Diffractive optical elements, Holograms, Spectroscopy, Ultrafast lasers

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Proceedings Article | 1 October 2009 Paper

Experimental detection of phase singularities using a Shack-Hartmann wavefront sensor

Kevin Murphy, Ruth Mackey, Chris Dainty

Proceedings Volume 7476, 74760O (2009) https://doi.org/10.1117/12.830078

KEYWORDS: Wavefront sensors, Spiral phase plates, Adaptive optics, Wavefronts, Spatial light modulators, Reconstruction algorithms, Sensors, Receivers, Cameras, Phase shift keying

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Proceedings Article | 18 April 2008 Paper

Branch point detection and correction using the branch point potential method

Kevin Murphy, Ruth Mackey, Chris Dainty

Proceedings Volume 6951, 695105 (2008) https://doi.org/10.1117/12.778743

KEYWORDS: Wavefronts, Adaptive optics, Turbulence, Wavefront sensors, Atmospheric propagation, Free space optics, Receivers, Reconstruction algorithms, Telecommunications, Atmospheric turbulence

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Showing 5 of 8 publications

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