Prof. Michael J. Withford Profile

Prof. Michael J. Withford

Professor at Macquarie Univ

SPIE Involvement:

Conference Program Committee | Author

Publications (59)

Proceedings Article | 13 March 2024 Presentation

Low-loss ultrafast laser inscribed photonics for space-division-multiplexed optical networks

Andrew Ross-Adams, T. Toney Fernandez, Elizabeth Arcadi, Glen Douglass, Mark Bakovic, Michael Withford, Simon Gross

Proceedings Volume PC12875, PC128750J (2024) https://doi.org/10.1117/12.3009842

KEYWORDS: Ultrafast lasers, Waveguides, Photonics, Optical networks, Optical fibers, Lithography, Glasses, Fabrication, Data communications, Space division multiplexing

Read Abstract +

Proceedings Article | 11 March 2024 Presentation + Paper

Improved integration density with ultra-fast laser written fiber fan-in/fan-out for broadband coupling to silicon photonics

A. Ross-Adams, M. Withford, S. Gross

Proceedings Volume 12892, 128920D (2024) https://doi.org/10.1117/12.3001212

KEYWORDS: Waveguides, Silicon, Refractive index, Glasses, Polarization, Fabrication, Silicon photonics, Optical fibers, Ultrafast phenomena

Read Abstract +

SPIE Journal Paper | 30 November 2023 Open Access

Machine-learning approach for optimal self-calibration and fringe tracking in photonic nulling interferometry

Barnaby Norris, Marc-Antoine Martinod, Peter Tuthill, Simon Gross, Nick Cvetojevic, Nemanja Jovanovic, Tiphaine Lagadec, Teresa Klinner-Teo, Olivier Guyon, Julien Lozi, Vincent Deo, Sébastien Vievard, Alex Arriola, Thomas Gretzinger, Jonathan Lawrence, Michael Withford

JATIS, Vol. 9, Issue 04, 048005, (November 2023) https://doi.org/10.1117/12.10.1117/1.JATIS.9.4.048005

KEYWORDS: Calibration, Data modeling, Signal to noise ratio, Education and training, Nulling interferometry, Equipment, Point spread functions, Wavefronts, Sensors, Optical path differences

Read Abstract +

DOWNLOAD PAPER

Proceedings Article | 26 August 2022 Presentation + Paper

Development of the four-telescope photonic nuller of Hi-5 for the characterization of exoplanets in the mid-IR

A. Sanny, S. Gross, L. Labadie, D. Defrère, A. Bigioli, R. Laugier, C. Dandumont, M. Withford

Proceedings Volume 12183, 1218316 (2022) https://doi.org/10.1117/12.2628903

KEYWORDS: Directional couplers, Nulling interferometry, Interferometry, Waveguides, Photometry, Integrated optics, Mid-IR

Read Abstract +

Proceedings Article | 26 August 2022 Presentation + Paper

Achromatic nulling interferometry and fringe tracking with 3D-photonic tricouplers with GLINT

Marc-Antoine Martinod, Teresa Klinner-Teo, Peter Tuthill, Simon Gross, Elizabeth Arcadi, Glen Douglass, Jacinda Webb, Barnaby Norris, Olivier Guyon, Julien Lozi, Tiphaine Lagadec, Nemanja Jovanovic, Nick Cvetojevic, Alexander Arriola, Thomas Gretzinger, Michael Withford, Jon Lawrence, Sergio Leon-Saval

Proceedings Volume 12183, 121830K (2022) https://doi.org/10.1117/12.2627978

KEYWORDS: Nulling interferometry, Waveguides, Stars, Exoplanets, Phase shifts, Telescopes, Integrated optics, Interferometry, Adaptive optics, Wavefronts

Read Abstract +

Proceedings Article | 26 August 2022 Presentation + Paper

Optimal self-calibration and fringe tracking in photonic nulling interferometers using machine learning

Barnaby R. Norris, Marc-Antoine Martinod, Peter Tuthill, Simon Gross, Nick Cvetojevic, Nemanja Jovanovic, Tiphaine Lagadec, Teresa Klinner-teo, Olivier Guyon, Julien Lozi, Vincent Deo, Sébastien Vievard, Alex Arriola, Thomas Gretzinger, Jon Lawrence, Michael Withford

Proceedings Volume 12183, 121831J (2022) https://doi.org/10.1117/12.2629873

KEYWORDS: Data modeling, Calibration, Wavefronts, Signal to noise ratio, Point spread functions, Nulling interferometry, Adaptive optics, Telescopes, Sensors, Machine learning

Read Abstract +

Proceedings Article | 1 September 2021 Presentation + Paper

Very high resolution spectro-interferometry with wavefront sensing capabilities on Subaru/SCExAO using photonics

S. Vievard, K. Ahn, A. Arriola, K. Barjot, N. Cvetojevic, V. Deo, T. Gretzinger, S. Gross, O. Guyon, E. Huby, N. Jovanovic, T. Kotani, S. Lacour, T. Lagadec, M. Lallement, V. Lapeyrere, J. Lozi, F. Marchis, G. Martin, M.-A. Martinod, B. Norris, G. Perrin, D. Rouan, N. Skaf, P. Tuthill, M. Withford, G. Duchêne

Proceedings Volume 11823, 118230C (2021) https://doi.org/10.1117/12.2594840

KEYWORDS: Telescopes, Wavefront sensors, Single mode fibers, Stars, Optical fibers, Interferometry, Diffraction, Wavefronts, Spatial resolution, Photonics

Read Abstract +

Proceedings Article | 13 December 2020 Presentation

The first multi-baseline and multi-band, photonic nuller at the Subaru telescope: the GLINT nulling interferometer

Marc-Antoine Martinod, Barnaby Norris, Tiphaine Lagadec, Nemanja Jovanovic, Nick Cvetojevic, Simon Gross, Alexander Arriola, Thomas Gretzinger, Michael Withford, Olivier Guyon, Julien Lozi, Jon Lawrence, Peter Tuthill, Sergio Leon-Saval

Proceedings Volume 11446, 114460G (2020) https://doi.org/10.1117/12.2560857

KEYWORDS: Nulling interferometry, Telescopes, Interferometers, Exoplanets, Atmospheric optics, Adaptive optics, Optical instrument design, Spatial resolution, Destructive interference, Prototyping

Read Abstract +

Proceedings Article | 13 December 2020 Paper

Towards the development of mid-infrared integrated optics in the renewed context of high-contrast interferometry

Tarun Kumar Sharma, Lucas Labadie, Dominik Strixner, Simon Gross, Thomas Gretzinger, Sascha Quanz, Denis Defrère, Sanny Ahmed, Michael Withford

Proceedings Volume 11446, 1144618 (2020) https://doi.org/10.1117/12.2561022

KEYWORDS: Interferometry, Mid-IR, Integrated optics, Nulling interferometry, Data processing, New and emerging technologies, Space operations, Exoplanets, Manufacturing, Chalcogenide glass

Read Abstract +

Proceedings Article | 3 January 2020 Paper

Ultrafast laser inscription of astrophotonic integrated optical circuits

S. Gross, T. Gretzinger, A. Arriola, G. Douglass, A. Ross-Adams, T. Fernandez, M. Withford

Proceedings Volume 11203, 112030W (2020) https://doi.org/10.1117/12.2549180

KEYWORDS: Waveguides, Ultrafast lasers, Astrophotonics, Photonic integrated circuits, Photonics, Glasses, Astronomy, Optical circuits, Rapid manufacturing

Read Abstract +

Proceedings Article | 3 January 2020 Paper

Imaging exoplanets with nulling interferometry using integrated-photonics: the GLINT project

M. Martinod, B. Norris, S. Gross, A. Arriola, T. Gretzinger, M. Withford, T. Lagadec, P. Tuthill

Proceedings Volume 11203, 112030R (2020) https://doi.org/10.1117/12.2539790

KEYWORDS: Exoplanets, Nulling interferometry, Photonics, Interferometry, Telescopes, Diffraction, Imaging spectroscopy, Waveguides, Stars, Astronomy

Read Abstract +

Proceedings Article | 9 July 2018 Presentation + Paper

Visible and near-infrared multilayer arrayed waveguide gratings: a novel approach for spectro-interferometry

G. Douglass, A. Arriola, S. Gross, M. Withford, E. Le Coarer, G. Martin

Proceedings Volume 10701, 107011S (2018) https://doi.org/10.1117/12.2313156

KEYWORDS: Waveguides, Visible radiation, Spectrometers, Diffraction, Astronomy, Fabrication, Spectral resolution, Interferometry, Visibility, Single mode fibers

Read Abstract +

Proceedings Article | 9 July 2018 Presentation + Paper

Photonics-based mid-infrared interferometry: 4-year results of the ALSI project and future prospects

Lucas Labadie, Stefano Minardi, Jan Tepper, Romina Diener, Balaji Muthusubramanian, Jörg-Uwe Pott, Stefan Nolte, Simon Gross, Alexander Arriola, Michael Withford

Proceedings Volume 10701, 107011R (2018) https://doi.org/10.1117/12.2312930

KEYWORDS: Waveguides, Interferometry, Directional couplers, Telescopes, ZBLAN, Visibility, Manufacturing, Polarization, Mid-IR, Birefringence

Read Abstract +

Proceedings Article | 9 July 2018 Presentation + Paper

Photonics-based mid-infrared interferometry: the challenges of polychromatic operation and comparative performances

Jan Tepper, Romina Diener, Lucas Labadie, Stefano Minardi, Simon Gross, Alexander Arriola, Michael Withford, Stefan Nolte

Proceedings Volume 10701, 107011B (2018) https://doi.org/10.1117/12.2307823

KEYWORDS: Waveguides, Interferometry, Integrated optics, Mid-IR, ZBLAN, Dispersion, Optical fibers, Silica, Visibility, Colorimetry

Read Abstract +

Proceedings Article | 9 July 2018 Presentation + Paper

GLINT South: a photonic nulling interferometer pathfinder at the Anglo-Australian Telescope for high contrast imaging of substellar companions

Tiphaine Lagadec, Barnaby Norris, Simon Gross, Alexander Arriola, Thomas Gretzinger, Nick Cvetojevic, Jon Lawrence, Michael Withford, Peter Tuthill

Proceedings Volume 10701, 107010V (2018) https://doi.org/10.1117/12.2313171

KEYWORDS: Stars, Waveguides, Telescopes, Nulling interferometry, Segmented mirrors, Planets, Astronomy, Mirrors, Adaptive optics, Glasses

Read Abstract +

Proceedings Article | 14 March 2018 Presentation

Laser written mode selective photonics: Future proofing multimode optical fibre communications (Conference Presentation)

Michael Withford, Simon Gross, Nicolas Riesen

Proceedings Volume 10544, 1054409 (2018) https://doi.org/10.1117/12.2284981

KEYWORDS: Multimode fibers, Femtosecond phenomena, Photonics, Fiber optic communications, Internet, Short haul, Optical fibers, Multiplexing

Read Abstract +

Proceedings Article | 16 February 2018 Presentation + Paper

Gradient-index beam shapers: fabricated devices and 3D design method

W. Minster Kunkel, Ali Ghoreyshi, Glen Douglass, Simon Gross, Michael Withford, James Leger

Proceedings Volume 10518, 105181S (2018) https://doi.org/10.1117/12.2290909

KEYWORDS: GRIN lenses, Refractive index, Waveguides, Beam shaping, Wavefronts, Femtosecond phenomena, Gaussian beams, Diffraction, Phase retrieval, Wave propagation

Read Abstract +

Proceedings Article | 19 September 2017 Presentation

Ultrafast laser written arrayed waveguide gratings with integrated photonic lanterns (Conference Presentation)

Glen Douglass, Simon Gross, Michael Withford

Proceedings Volume 10382, 103820S (2017) https://doi.org/10.1117/12.2274494

KEYWORDS: Waveguides, Spectrographs, Femtosecond phenomena, Fabrication, Spectral resolution, Ultrafast lasers, Waveguide lasers, Integrated photonics, Telecommunications, Sensors

Read Abstract +

Proceedings Article | 21 April 2017 Presentation

A passively mode-locked sub-picosecond Ho3+,Pr3+-doped fluoride fiber laser operating at 2.86 µm (Conference Presentation)

Sergei Antipov, Stuart Jackson, Michael Withford, Alexander Fürbach

Proceedings Volume 10083, 100831A (2017) https://doi.org/10.1117/12.2253510

KEYWORDS: Ultrafast phenomena, Ultrafast measurement systems, Tissues, Fiber lasers, Mode locking, Polarization, Resonators, Laser resonators, Semiconductor lasers, Liquids

Read Abstract +

Proceedings Article | 22 July 2016 Paper

Refractive index change mechanisms in different glasses induced by femtosecond laser irradiation

A. Fuerbach, S. Gross, D. Little, A. Arriola, M. Ams, P. Dekker, M. Withford

Proceedings Volume 9983, 99830W (2016) https://doi.org/10.1117/12.2237368

KEYWORDS: Glasses, Femtosecond phenomena, Refractive index, Fabrication, Waveguides, Raman spectroscopy, Pulsed laser operation, Annealing, Photonics, ZBLAN

Read Abstract +

Proceedings Article | 1 March 2016 Paper

Engineering reconfigurable laser-written circuits for practical quantum metrology

Zachary Chaboyer, Alex Stokes, M. Steel, Michael Withford

Proceedings Volume 9750, 97500U (2016) https://doi.org/10.1117/12.2214048

KEYWORDS: Interferometers, Metrology, Waveguides, Glasses, Phase shifts, Waveguide modes, Laser metrology, Precision measurement, Phase measurement, Fabrication, Photons, Laser ablation, Picosecond phenomena

Read Abstract +

Proceedings Article | 4 March 2015 Paper

Laser written multiport quantum circuits

Zachary Chaboyer, Thomas Meany, L. Helt, M. Steel, Michael Withford

Proceedings Volume 9377, 93770Y (2015) https://doi.org/10.1117/12.2081030

KEYWORDS: Waveguides, Beam splitters, Photons, Interferometers, Glasses, Single photon, Quantum circuits, Rapid manufacturing, Femtosecond phenomena

Read Abstract +

Proceedings Article | 24 July 2014 Paper

High performance 3D waveguide architecture for astronomical pupil-remapping interferometry

Simon Gross, Barnaby Norris, Nick Cvetojevic, Nemanja Jovanovic, Alexander Arriola Martiarena, Paul Stewart, Jon Lawrence, Michael Withford, Peter Tuthill

Proceedings Volume 9146, 91461B (2014) https://doi.org/10.1117/12.2057282

KEYWORDS: Waveguides, Planets, Astronomy, Photonics, Interferometry, Glasses, Stars, Microelectromechanical systems, Single mode fibers, Adaptive optics

Read Abstract +

Proceedings Article | 8 March 2014 Paper

Femtosecond laser processing in magneto-optical glasses

Qiang Liu, Simon Gross, M. Withford, M. Steel

Proceedings Volume 8988, 89880D (2014) https://doi.org/10.1117/12.2038847

KEYWORDS: Waveguides, Glasses, Annealing, Femtosecond phenomena, Wave propagation, Laser systems engineering, Optical isolators, Light wave propagation, Microscopy, Pulsed laser operation

Read Abstract +

Proceedings Article | 19 February 2014 Paper

Hybrid integration for spatially multiplexed single-photon generation

Thomas Meany, Lutfi Ngah, Matthew Collins, Alex Clark, Robert Williams, Benjamin Eggleton, M. Steel, Michael Withford, Olivier Alibart, Sébastien Tanzilli

Proceedings Volume 8997, 89970P (2014) https://doi.org/10.1117/12.2055265

KEYWORDS: Waveguides, Wavelength division multiplexing, Fiber Bragg gratings, Single photon, Multiplexing, Sensors, Femtosecond phenomena, Lithium niobate, Pulsed laser operation, Photonics

Read Abstract +

Proceedings Article | 24 September 2013 Paper

Ultrafast laser inscribed 3D integrated photonics

S. Gross, A. Arriola, G. Palmer, N. Jovanovic, I. Spaleniak, T. Meany, Y. Duan, Q. Liu, P. Dekker, D. Lancaster, H. Ebendorff-Heidepriem, P. Tuthill, B. Norris, A. Fuerbach, M. Ireland, M. Steel, M. Withford

Proceedings Volume 8876, 887604 (2013) https://doi.org/10.1117/12.2025535

KEYWORDS: Waveguides, Glasses, Ultrafast lasers, Photonics, Femtosecond phenomena, Refractive index, Waveguide lasers, Mid-IR, ZBLAN, Integrated photonics

Read Abstract +

Proceedings Article | 15 March 2013 Paper

The influence of distributed rare earth dopant on the performance of waveguide lasers fabricated by the femtosecond laser direct-write technique

Yuwen Duan, Aaron McKay, Peter Dekker, M.J. Steel, Michael Withford

Proceedings Volume 8611, 86110W (2013) https://doi.org/10.1117/12.2002249

KEYWORDS: Waveguide lasers, Waveguides, Glasses, Femtosecond phenomena, Fabrication, Ytterbium, Cladding, Absorption, Ions, Data modeling

Read Abstract +

Proceedings Article | 6 March 2013 Paper

Versatile fs laser-written glass chip lasers

D. Lancaster, S. Gross, A. Fuerbach, H. Ebendorff Heidepriem, T. Monro, M. Withford

Proceedings Volume 8599, 859907 (2013) https://doi.org/10.1117/12.2012519

KEYWORDS: Waveguides, Glasses, ZBLAN, Cladding, Waveguide lasers, Fiber lasers, Laser applications, Laser glasses, Laser damage threshold, Coating

Read Abstract +

Proceedings Article | 24 September 2012 Paper

Redesign of the integrated photonic spectrograph for improved astronomical performance

Nick Cvetojevic, Nemanja Jovanovic, Jon Lawrence, Michael Withford, Joss Bland-Hawthorn

Proceedings Volume 8446, 84463I (2012) https://doi.org/10.1117/12.925787

KEYWORDS: Waveguides, Spectrographs, Astronomy, Spectral resolution, Photonics, Prototyping, Integrated photonics, Semiconducting wafers, Optical design, Single mode fibers

Read Abstract +

Proceedings Article | 13 September 2012 Paper

Enabling photonic technologies for seeing-limited telescopes: fabrication of integrated photonic lanterns on a chip

Izabela Spaleniak, Nemanja Jovanovic, Simon Gross, Michael Ireland, Jon Lawrence, Michael Withford

Proceedings Volume 8450, 845015 (2012) https://doi.org/10.1117/12.925264

KEYWORDS: Waveguides, Glasses, Telescopes, Integrated photonics, Astronomy, Refractive index, Objectives, Absorption, Astronomical telescopes, Single mode fibers

Read Abstract +

Proceedings Article | 12 September 2012 Paper

Progress and challenges with the Dragonfly instrument; an integrated photonic pupil-remapping interferometer

Nemanja Jovanovic, Peter Tuthill, Barnaby Norris, Simon Gross, Paul Stewart, Ned Charles, Sylvestre Lacour, Jon Lawrence, Gordon Robertson, Alexander Fuerbach, Michael Withford

Proceedings Volume 8445, 844505 (2012) https://doi.org/10.1117/12.926012

KEYWORDS: Waveguides, Fringe analysis, Telescopes, Microelectromechanical systems, Prototyping, Interferometers, Astronomy, Mirrors, Interferometry, Integrated photonics

Read Abstract +

Proceedings Article | 11 February 2011 Paper

Direct laser written waveguide coupler with an optically tunable splitting ratio

M. Ams, R. Williams, M. Withford

Proceedings Volume 7925, 79250K (2011) https://doi.org/10.1117/12.875959

KEYWORDS: Waveguides, Refractive index, Femtosecond phenomena, Borosilicate glass, Absorption, Waveguide lasers, Ytterbium, Glasses, Single mode fibers, Beam splitters

Read Abstract +

Proceedings Article | 11 February 2011 Paper

Fs laser induced apodised Bragg waveguides in fused silica

Christian Voigtländer, Peter Zeil, Jens Thomas, Martin Ams, Robert Williams, Michael Withford, Andreas Tünnermann, Stefan Nolte

Proceedings Volume 7925, 79250Y (2011) https://doi.org/10.1117/12.886306

KEYWORDS: Refractive index, Modulation, Waveguides, Fiber Bragg gratings, Femtosecond phenomena, Silica, Apodization, Laser systems engineering, Reflectivity, Fabrication

Read Abstract +

Proceedings Article | 23 July 2010 Paper

Fibre Bragg gratings for temporal spectral astronomy

Geraldine Mariën, Nick Cvetojevic, Nemanja Jovanovic, Judith Dawes, Joss Bland-Hawthorn, Roger Haynes, Jon Lawrence, Quentin Parker, Michael Withford

Proceedings Volume 7739, 77392C (2010) https://doi.org/10.1117/12.856784

KEYWORDS: Fiber Bragg gratings, Astronomy, Optical filters, Reflectivity, Stars, Spectral resolution, Telescopes, Optical fibers, Single mode fibers, Signal to noise ratio

Read Abstract +

Proceedings Article | 22 July 2010 Paper

Direct laser written multimode waveguides for astronomical applications

Nemanja Jovanovic, Simon Gross, Christopher Miese, Alexander Fuerbach, Jon Lawrence, Michael Withford

Proceedings Volume 7739, 773923 (2010) https://doi.org/10.1117/12.856754

KEYWORDS: Waveguides, Cladding, Astronomy, Multimode fibers, Glasses, Optical fibers, Refractive index, Objectives, Structural design, Light wave propagation

Read Abstract +

Proceedings Article | 22 July 2010 Paper

Photonic technologies for a pupil remapping interferometer

Peter Tuthill, Nemanja Jovanovic, Sylvestre Lacour, Andrew Lehmann, Martin Ams, Graham Marshall, Jon Lawrence, Michael Withford, Gordon Robertson, Michael Ireland, Benjamin Pope, Paul Stewart

Proceedings Volume 7734, 77341P (2010) https://doi.org/10.1117/12.856770

KEYWORDS: Waveguides, Interferometers, Telescopes, Spatial filters, Adaptive optics, Signal to noise ratio, Single mode fibers, Interferometry, Space telescopes, Prototyping

Read Abstract +

Proceedings Article | 5 June 2010 Paper

Ultrafast Bessel beams for high aspect ratio taper free micromachining of glass

M. Bhuyan, F. Courvoisier, P.-A. Lacourt, M. Jacquot, L. Furfaro, M. Withford, J. Dudley

Proceedings Volume 7728, 77281V (2010) https://doi.org/10.1117/12.854767

KEYWORDS: Bessel beams, Glasses, Femtosecond phenomena, Laser ablation, Micromachining, Ultrafast phenomena, Ultrafast lasers, Plasma, Laser processing, Photonics

Read Abstract +

Proceedings Article | 25 February 2010 Paper

Mode selective fiber Bragg gratings

Jens Thomas, Christian Voigtländer, Stefan Nolte, Andreas Tünnermann, Nemanja Jovanovic, Graham Marshall, Michael Withford, Michael Steel

Proceedings Volume 7589, 75890J (2010) https://doi.org/10.1117/12.843805

KEYWORDS: Fiber Bragg gratings, Cladding, Ultrafast phenomena, Reflectivity, Fiber lasers, High power fiber lasers, Laser systems engineering, Femtosecond phenomena, Refractive index, Single mode fibers

Read Abstract +

Proceedings Article | 25 February 2010 Paper

Direct femtosecond laser written waveguides in bulk Ti3+:sapphire

Simon Gross, Michael Withford, Alexander Fuerbach

Proceedings Volume 7589, 75890U (2010) https://doi.org/10.1117/12.841462

KEYWORDS: Waveguides, Luminescence, Crystals, Polarization, Sapphire, Single mode fibers, Birefringence, Ultrafast phenomena, Refractive index, Near field

Read Abstract +

Proceedings Article | 17 February 2010 Paper

Optically switched erbium fiber laser using a tunable fiber-Bragg grating

Robert Williams, Nemanja Jovanovic, Graham Marshall, Michael Withford

Proceedings Volume 7580, 75800P (2010) https://doi.org/10.1117/12.839450

KEYWORDS: Fiber Bragg gratings, Fiber lasers, Diodes, Erbium, Q switched lasers, Refractive index, Q switching, Switching, Q switched fiber lasers, Modulation

Read Abstract +

Proceedings Article | 5 October 2009 Paper

Temperature and strain discriminating sensor based on the monitoring of cladding modes of a single femtosecond inscribed grating

Nemanja Jovanovic, Robert Williams, Jens Thomas, M. Steel, Graham Marshall, Alexander Fuerbach, Stefan Nolte, Andreas Tünnermann, Michael Withford

Proceedings Volume 7503, 750336 (2009) https://doi.org/10.1117/12.835094

KEYWORDS: Fiber Bragg gratings, Sensors, Cladding, Femtosecond phenomena, Temperature metrology, Refractive index, Optical fibers, Thermal optics, Semiconductor lasers, Photonics

Read Abstract +

Proceedings Article | 18 May 2009 Paper

Photo-erasure of type-II femtosecond laser written Bragg gratings employed as high reflectors in moderate power Q-switch fibre laser

Mattias Åslund, Nemanja Jovanovic, Stuart Jackson, John Canning, Graham Marshall, Alexander Fuerbach, Michael Withford, Kevin Cook

Proceedings Volume 7356, 73561I (2009) https://doi.org/10.1117/12.820586

KEYWORDS: Fiber Bragg gratings, Femtosecond phenomena, Absorption, Q switched fiber lasers, Reflectors, Fiber lasers, Ions, Refractive index, Glasses, Optical fibers

Read Abstract +

Proceedings Article | 23 July 2008 Paper

Focal ratio degradation: a new perspective

Dionne Haynes, Michael Withford, Judith Dawes, Roger Haynes, Joss Bland-Hawthorn

Proceedings Volume 7018, 70182U (2008) https://doi.org/10.1117/12.788735

KEYWORDS: Scattering, Surface roughness, Diffusion, Polishing, Laser scattering, Light scattering, Convolution, Instrument modeling, Astronomy, Multimode fibers

Read Abstract +

Proceedings Article | 17 January 2008 Paper

Self-assembly around curved surfaces

Luke Stewart, Graham Marshall, Judith Dawes, Michael Withford, Adel Rahmani

Proceedings Volume 6801, 68011A (2008) https://doi.org/10.1117/12.769338

KEYWORDS: Optical spheres, Photonic crystals, Photonics, Optical fibers, Microscopes, Crystals, Molecular self-assembly, Scanning electron microscopy, Photonic crystal fibers, Refractive index

Read Abstract +

Proceedings Article | 11 January 2008 Paper

Photodarkening study of gratings written into rare-earth doped optical fibres using a femtosecond laser

Mattias Åslund, Nemanja Jovanovic, Nathaniel Groothoff, John Canning, Graham Marshall, Stuart Jackson, Alex Fuerbach, Michael Withford

Proceedings Volume 6800, 68000V (2008) https://doi.org/10.1117/12.760829

KEYWORDS: Fiber Bragg gratings, Femtosecond phenomena, Scattering, Refractive index, Light scattering, Ytterbium, Mie scattering, Annealing, Laser scattering, Modulation

Read Abstract +

Proceedings Article | 8 January 2008 Paper

Compact, all-fibre, linearly polarized, single-mode Ytterbium-doped fibre laser utilizing point-by-point inscribed intra-core fibre Bragg gratings

Nemanja Jovanovic, Graham Marshall, Alexander Fuerbach, Graham Town, Michael Withford, Shayne Bennetts, David Lancaster

Proceedings Volume 6801, 68010O (2008) https://doi.org/10.1117/12.759300

KEYWORDS: Fiber Bragg gratings, Fiber lasers, Output couplers, Polarization, Semiconductor lasers, Reflectors, Ytterbium, Phase modulation, Absorption, Femtosecond phenomena

Read Abstract +

Proceedings Article | 8 January 2008 Paper

Characterization of fs-laser written refractive index changes using near-field scanning optical microscopy

D. Little, P. Dekker, A. Rahmani, J. Dawes, G. Marshall, M. Withford

Proceedings Volume 6801, 680119 (2008) https://doi.org/10.1117/12.761087

KEYWORDS: Waveguides, Near field scanning optical microscopy, Refractive index, Optical microscopes, Polishing, Interfaces, Femtosecond phenomena, Dielectrics, Glasses, Silica

Read Abstract +

Proceedings Article | 8 January 2008 Paper

Energy exchange between orthogonally polarized waves by cascaded quasi-phase-matched processes

B. Johnston, P. Dekker, S. Saltiel, M. Withford, Y. Kivshar

Proceedings Volume 6801, 680116 (2008) https://doi.org/10.1117/12.759753

KEYWORDS: Second-harmonic generation, Crystals, Lithium niobate, Polarization, Refractive index, Nonlinear optics, Phase shifts, Temperature metrology, Nonlinear crystals, Phase matching

Read Abstract +

Proceedings Article | 14 February 2007 Paper

Simultaneous SHG of orthogonally polarized fundamentals in single QPM crystals

Benjamin Johnston, Solomon Saltiel, Michael Withford, Yuri Kivshar

Proceedings Volume 6455, 64550Q (2007) https://doi.org/10.1117/12.699850

KEYWORDS: Polarization, Crystals, Second-harmonic generation, Lithium niobate, Laser crystals, Nonlinear crystals, Harmonic generation, Polishing, Fabrication, Switching

Read Abstract +

Proceedings Article | 20 April 2006 Paper

Femtosecond inscription of wavelength specific features in optical waveguide structures

Graham Marshall, Martin Ams, Michael Withford

Proceedings Volume 6183, 61830Q (2006) https://doi.org/10.1117/12.663177

KEYWORDS: Waveguides, Fiber Bragg gratings, Glasses, Femtosecond phenomena, Refractive index, Silica, Optical fibers, Objectives, Microscopes, Waveguide lasers

Read Abstract +

Proceedings Article | 14 April 2006 Paper

Effects of laser beam shapes on depths of penetration in dermatology

S. Saghafi, M. Withford, M. Farhadi, R. Ghaderi, A. Granmayeh, Z. Ghoranneviss, F. Moravej

Proceedings Volume 6191, 619107 (2006) https://doi.org/10.1117/12.662167

KEYWORDS: Beam shaping, Skin, Tissues, Gaussian beams, Laser vision correction, Tissue optics, Beam splitters, Optical components, Dermatology, Laser therapeutics

Read Abstract +

For many medical laser applications, a particular beam shape is required. The output beam of a laser can be approximated by a Gaussian, higher-order Gaussian, annular or a flat-top (uniform) distribution. Here, we investigate, analytically and experimentally, the effects of laser beam shapes on the depths of penetration in treatments of any types of vascular malformation. In order to do this, the physical and optical parameters of the skin must be known and measured correctly. Using the Monte-Carlo method for seven layers of skin, a software predicting the beam propagation and intensity distribution inside of tissue has been developed in our centre. In this paper, a 15 watts copper vapour laser producing (511nm and 578 nm) for treatments of patients having PWS (Port Wine Stains) of different sizes is employed. The output beam of this laser was Gaussian. We have designed a beam homogenizer converting a Gaussian beam into flat-top distribution. Therefore, the effects of the laser irradiance beam shape (before and after beam shaping) on the depth of penetration have been investigated before people's treatments. Initially, two laser beams having Gaussian output distribution of the same power are considered. The diameter of one beam is 5mm and the other one is 10 mm. The intensity distribution of these beam inside of similar tissues are predicted and it is concluded that for deep but small size PWS the Gaussian beam having smaller beam diameter is more suitable than the larger spot size. Then, the beam intensity distribution inside of the same tissue (similar parameters) for two flat-top beams of the same power but different diameters (one is 5mm and the other is 10 mm) is calculated. It can be seen that the flat top beam of bigger spot-size has smaller penetration depth but it illuminates a larger area uniformly (suitable for large but not deep area). The depth of penetration of flat-top beam with smaller spot size is deeper but it illuminates a smaller area uniformly and is suitable for treatments of patients with small but deep PWS. Using a low power laser, we have been able to image the PWS area and roughly determine the depths of malformations. Finally, depends on the size, depth and shapes of the area the required beam shape can be chosen. A clinical protocol is developed for 25 patients and it is shown an extreme improvement in related medical procedures.

Proceedings Article | 25 March 2004 Paper

Fabrication of photonic devices using novel laser-assisted methods

Michael Withford, Andrew Lee, Benjamin Johnston, Martin Ams, Judith Dawes, James Piper

Proceedings Volume 5277, (2004) https://doi.org/10.1117/12.524399

KEYWORDS: Photonic devices, Photonics, Packaging, Laser processing, Micromachining, Optical lithography, Electronics, Rapid manufacturing, Lithium niobate, Photonic crystals

Read Abstract +

Proceedings Article | 19 November 2003 Paper

Beam propagation analysis in unstable laser resonators (ULR): low to high magnificaiton

Saiedeh Saghafi, Michael Withford, James Piper

Proceedings Volume 4829, (2003) https://doi.org/10.1117/12.523670

KEYWORDS: Laser resonators, Resonators, Beam analyzers, Near field, Laser beam propagation, Gaussian beams, Reflectors, Mirrors, Copper vapor lasers, Superposition

Read Abstract +

Proceedings Article | 10 November 2003 Paper

Specific output power scaling of kinetically-enhanced copper vapor lasers

Richard Mildren, M. Withford, J. Piper, G. Marshall

Proceedings Volume 5120, (2003) https://doi.org/10.1117/12.515483

KEYWORDS: Copper, Copper vapor lasers, Plasma, Silica, Resonators, Chemical species, Ionization, Neon, Ceramics, Pulsed laser operation

Read Abstract +

Proceedings Article | 3 April 2000 Paper

High-average-power high-beam-quality vis-UV sources based on kinetically enhanced copper vapor lasers

Daniel Brown, Michael Withford, Robert Carman, Richard Mildren, James Piper

Proceedings Volume 3889, (2000) https://doi.org/10.1117/12.380892

KEYWORDS: Plasma, Copper, Copper vapor lasers, Pulsed laser operation, Resonators, Neon, Computer simulations, Halogens, Optical amplifiers, Oscillators

Read Abstract +

Proceedings Article | 7 February 2000 Paper

Optimization of trepanning strategies for micromachining of polymers with high-pulse-rate UV lasers

Elizabeth Illy, Daniel Brown, Michael Withford, James Piper

Proceedings Volume 3888, (2000) https://doi.org/10.1117/12.377071

KEYWORDS: Etching, Polymethylmethacrylate, Polymers, Micromachining, Ultraviolet radiation, Pulsed laser operation, Laser ablation, Copper vapor lasers, Excimer lasers, Ultraviolet sources

Read Abstract +

Proceedings Article | 1 February 2000 Paper

Exploring the explosive ablation regime of metals in nanosecond micromachining

Jennifer Fishburn, Richard Mildren, Daniel Kapitan, Michael Withford, Daniel Brown, James Piper

Proceedings Volume 3885, (2000) https://doi.org/10.1117/12.376996

KEYWORDS: Metals, Laser ablation, Aluminum, Molybdenum, Copper, Titanium, Indium, Tungsten, Explosives, Micromachining

Read Abstract +

Proceedings Article | 4 April 1997 Paper

Performance enhancement of elemental copper vapor lasers by bromine and hydrogenated bromine additives

Robert Carman, Michael Withford, Daniel Brown, James Piper

Proceedings Volume 3092, (1997) https://doi.org/10.1117/12.270156

KEYWORDS: Bromine, Copper, Halogens, Plasma, Copper vapor lasers, Neon, Hydrogen, Pulsed laser operation, Molecules, Ions

Read Abstract +

Proceedings Article | 8 April 1996 Paper

High-speed micromachining with UV-copper vapor lasers

Elizabeth Illy, Alison Glover, Michael Withford, James Piper

Proceedings Volume 2703, (1996) https://doi.org/10.1117/12.237754

KEYWORDS: Etching, Laser ablation, Micromachining, Neodymium lasers, Excimer lasers, Polymers, Laser applications, Signal attenuation, Crystals, Camera shutters

Read Abstract +

Showing 5 of 59 publications

Conference Committee Involvement (16)

Laser-based Micro- and Nanoprocessing XIX

25 January 2025 | San Francisco, United States

Laser-based Micro- and Nanoprocessing XVIII

29 January 2024 | San Francisco, California, United States

Laser-based Micro- and Nanoprocessing XVII

31 January 2023 | San Francisco, California, United States

Laser-based Micro- and Nanoprocessing XVI

25 January 2022 | San Francisco, California, United States

Laser-based Micro- and Nanoprocessing XV

6 March 2021 | Online Only, California, United States

Laser-based Micro- and Nanoprocessing XIV

3 February 2020 | San Francisco, California, United States

Laser-based Micro- and Nanoprocessing XIII

5 February 2019 | San Francisco, California, United States

Laser-based Micro- and Nanoprocessing XII

30 January 2018 | San Francisco, California, United States

Laser-based Micro- and Nanoprocessing XI

31 January 2017 | San Francisco, California, United States

Laser-based Micro- and Nanoprocessing X

16 February 2016 | San Francisco, California, United States

Laser-based Micro- and Nanoprocessing IX

10 February 2015 | San Francisco, California, United States

Laser-based Micro- and Nano-Processing VIII

5 February 2014 | San Francisco, California, United States

SPIE Smart Nano-Micro Materials and Devices

5 December 2011 | Melbourne, Australia

Laser Applications in Microelectronic and Optoelectronic Manufacturing XIV

26 January 2009 | San Jose, California, United States

Commercial and Biomedical Applications of Ultrafast Lasers IX

25 January 2009 | San Jose, California, United States

Photonics: Design, Technology, and Packaging III

5 December 2007 | Canberra, ACT, Australia

Showing 5 of 16 Conference Committees

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years