Ms. Emma Y. Lindley Profile

Emma Y. Lindley

at Univ of Sydney

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Author

Publications (6)

Proceedings Article | 6 July 2018 Presentation + Paper

PRAXIS: an OH suppression optimised near infrared spectrograph

S. Ellis, S. Bauer, C. Bacigalupo, J. Bland-Hawthorn, J. Bryant, S. Case, R. Content, T. Fechner, D. Giannone, R. Haynes, E. Hernandez, A. Horton, U. Klauser, J. Lawrence, S. Leon-Saval, E. Lindley, H.-G. Löhmannsröben, S.-S. Min, N. Pai, M. Roth, K. Shortridge, L. Waller, Pascal Xavier, Ross Zhelem

Proceedings Volume 10702, 107020P (2018) https://doi.org/10.1117/12.2311898

KEYWORDS: Spectrographs, Bragg gratings, Fiber Bragg gratings, Telescopes, Near infrared, Diffraction gratings, Optical design, Near infrared spectroscopy, Optical filters

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Proceedings Article | 9 August 2016 Paper

PRAXIS: a near infrared spectrograph optimised for OH suppression

S. Ellis, S. Bauer, J. Bland-Hawthorn, S. Case, R. Content, T. Fechner, D. Giannone, R. Haynes, E. Hernandez, A. Horton, U. Klauser, J. Lawrence, S. Leon-Saval, E. Lindley, H.-G. Löhmannsröben, S.-S. Min, N. Pai, M. Roth, K. Shortridge, Nicholas Staszak, Julia Tims, Pascal Xavier, Ross Zhelem

Proceedings Volume 9908, 99084A (2016) https://doi.org/10.1117/12.2232115

KEYWORDS: Fiber Bragg gratings, Spectrographs, Sensors, Near infrared, Astronomy, Fiber Bragg gratings, Near infrared, Optical design, Telescopes, Near infrared spectroscopy, Metrology, Spectroscopes

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Proceedings Article | 22 July 2016 Paper

Post-inscription tuning of multicore fiber Bragg gratings

Emma Lindley, Seong-sik Min, Sergio Leon-Saval, Joss Bland-Hawthorn

Proceedings Volume 9912, 99121Z (2016) https://doi.org/10.1117/12.2234245

KEYWORDS: Fiber Bragg gratings, Coating, Astronomy, Cladding, Ultraviolet radiation, Metals, Refractive index, Silver, Photonics, Atmospheric optics

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Proceedings Article | 22 July 2016 Paper

Multicore fibre technology: the road to multimode photonics

J. Bland-Hawthorn, Seong-Sik Min, Emma Lindley, Sergio Leon-Saval, Simon Ellis, Jon Lawrence, Nicolas Beyrand, Martin Roth, Hans-Gerd Löhmannsröben, Sylvain Veilleux

Proceedings Volume 9912, 99121O (2016) https://doi.org/10.1117/12.2231924

KEYWORDS: Photonics, Fiber Bragg gratings, Phase modulation, Mirrors, Ultraviolet radiation, Refractive index, Single mode fibers, Beam splitters, Interferometers, Telescopes

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Proceedings Article | 7 August 2014 Paper

Core-to-core uniformity improvement in multi-core fiber Bragg gratings

Emma Lindley, Seong-Sik Min, Sergio Leon-Saval, Nick Cvetojevic, Nemanja Jovanovic, Joss Bland-Hawthorn, Jon Lawrence, Itandehui Gris-Sanchez, Tim Birks, Roger Haynes, Dionne Haynes

Proceedings Volume 9151, 91515F (2014) https://doi.org/10.1117/12.2055623

KEYWORDS: Capillaries, Cladding, Fiber Bragg gratings, Polishing, Refractive index, Single mode fibers, Ultraviolet radiation, Silica, Astronomy, Optical simulations

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Proceedings Article | 28 July 2014 Paper

PRAXIS: low thermal emission high efficiency OH suppressed fibre spectrograph

Robert Content, Joss Bland-Hawthorn, Simon Ellis, Luke Gers, Roger Haynes, Anthony Horton, Jon Lawrence, Sergio Leon-Saval, Emma Lindley, Seong-Sik Min, Keith Shortridge, Nick Staszak, Christopher Trinh, Pascal Xavier, Ross Zhelem

Proceedings Volume 9151, 91514W (2014) https://doi.org/10.1117/12.2055597

KEYWORDS: Spectrographs, Fiber Bragg gratings, Sensors, Microlens, Multimode fibers, Telescopes, Cameras, Absorption, Glasses, Optical design

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PRAXIS is a second generation instrument that follows on from GNOSIS, which was the first instrument using fibre Bragg gratings for OH suppression to be deployed on a telescope. The Bragg gratings reflect the NIR OH lines while being transparent to the light between the lines. This gives in principle a much higher signal-noise ratio at low resolution spectroscopy but also at higher resolutions by removing the scattered wings of the OH lines. The specifications call for high throughput and very low thermal and detector noise so that PRAXIS will remain sky noise limited even with the low sky background levels remaining after OH suppression. The optical and mechanical designs are presented. The optical train starts with fore-optics that image the telescope focal plane on an IFU which has 19 hexagonal microlenses each feeding a multi-mode fibre. Seven of these fibres are attached to a fibre Bragg grating OH suppression system while the others are reference/acquisition fibres. The light from each of the seven OH suppression fibres is then split by a photonic lantern into many single mode fibres where the Bragg gratings are imprinted. Another lantern recombines the light from the single mode fibres into a multi-mode fibre. A trade-off was made in the design of the IFU between field of view and transmission to maximize the signal-noise ratio for observations of faint, compact objects under typical seeing. GNOSIS used the pre-existing IRIS2 spectrograph while PRAXIS will use a new spectrograph specifically designed for the fibre Bragg grating OH suppression and optimised for 1.47 μm to 1.7 μm (it can also be used in the 1.09 μm to 1.26 μm band by changing the grating and refocussing). This results in a significantly higher transmission due to high efficiency coatings, a VPH grating at low incident angle and optimized for our small bandwidth, and low absorption glasses. The detector noise will also be lower thanks to the use of a current generation HAWAII-2RG detector. Throughout the PRAXIS design, from the fore-optics to the detector enclosure, special care was taken at every step along the optical path to reduce thermal emission or stop it leaking into the system. The spectrograph design itself was particularly challenging in this aspect because practical constraints required that the detector and the spectrograph enclosures be physically separate with air at ambient temperature between them. At present, the instrument uses the GNOSIS fibre Bragg grating OH suppression unit. We intend to soon use a new OH suppression unit based on multicore fibre Bragg gratings which will allow an increased field of view per fibre. Theoretical calculations show that the gain in interline sky background signal-noise ratio over GNOSIS may very well be as high as 9 with the GNOSIS OH suppression unit and 17 with the multicore fibre OH suppression unit.

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