Dr. Peter Knowles Profile

Dr. Peter Knowles

Technical Manager at Leonardo MW Ltd

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Author

Publications (22)

Proceedings Article | 15 March 2018 Open Access

TWINKLE: a low earth orbit visible and infrared exoplanet spectroscopy observatory

G. Savini, M. Tessenyi, G. Tinetti, C. Arena, J. Tennyson, T. Zingales, En. Pascale, R. Sudiwala, A. Papageorgiou, S. Sarkar, P. A. Ade, M. Griffin, K. Barnes, L. Hipwood, P. Knowles, M. Patel, M. Leese, J. Mason, M. Crook, I. Tosh, A. Saad, P. Eccleston, B. Shaughnessy, T. Brooke, M. Wells, I. Bryson, A. Macleod, W. Taylor, N. Bezawada, G. Wright, S. Jason, J. Friend, J. Williams, G. Johnston, S. Prasad, A. Vora, C. Saunders, B. Winter, P. Curry, A. Smith

Proceedings Volume 9904, 99044M (2018) https://doi.org/10.1117/12.2233691

KEYWORDS: Sensors, Telescopes, Spectroscopy, Space telescopes, Visible radiation, Mirrors, Infrared spectroscopy, Space operations, Exoplanets, Satellites

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Proceedings Article | 17 November 2017 Open Access

Advances in SELEX ES infrared detectors for space and astronomy

P. Knowles, L. Hipwood, I. Baker, H. Weller

Proceedings Volume 10563, 1056312 (2017) https://doi.org/10.1117/12.2304267

KEYWORDS: Near infrared, Short wave infrared radiation, Astronomy, Semiconducting wafers, Sensors, Mercury cadmium telluride, Readout integrated circuits, Avalanche photodetectors, Astronomical imaging, Infrared detectors

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Selex ES produces a wide range of infrared detectors from mercury cadmium telluride (MCT) and triglycine sulfate (TGS), and has supplied both materials into space programmes spanning a period of over 40 years. Current development activities that underpin potential future space missions include large format arrays for near- and short-wave infrared (NIR and SWIR) incorporating radiation-hard designs and suppression of glow. Improved heterostructures are aimed at the reduction of dark currents and avalanche photodiodes (APDs), and parallel studies have been undertaken for low-stress MCT array mounts. Much of this development work has been supported by ESA, UK Space, and ESO, and some has been performed in collaboration with the UK Astronomy Technology Centre and E2V.

This paper focuses on MCT heterostructure developments and novel design elements in silicon read-out chips (ROICs). The 2048 x 2048 element, 17um pitch ROIC for ESA’s SWIR array development forms the basis for the largest cooled infrared detector manufactured in Europe. Selex ES MCT is grown by metal organic vapour phase epitaxy (MOVPE), currently on 75mm diameter GaAs substrates. The MCT die size of the SWIR array is 35mm square and only a single array can be printed on the 75mm diameter wafer, utilising only 28% of the wafer area. The situation for 100mm substrates is little better, allowing only 2 arrays and 31% utilisation. However, low cost GaAs substrates are readily available in 150mm diameter and the MCT growth is scalable to this size, offering the real possibility of 6 arrays per wafer with 42% utilisation.

A similar 2k x 2k ROIC is the goal of ESA’s NIR programme, which is currently in phase 2 with a 1k x 1k demonstrator, and a smaller 320 x 256 ROIC (SAPHIRA) has been designed for ESO for the adaptive optics application in the VLT Gravity instrument. All 3 chips have low noise source-follower architecture and are enabled for MCT APD arrays, which have been demonstrated by ESO to be capable of single photon detection. The possibility therefore exists in the near future of demonstrating a photon counting, 2k x 2k SWIR MCT detector manufactured on an affordable wafer scale of 6 arrays per wafer.

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Proceedings Article | 2 May 2016 Paper

Infrared detectors for Earth observation

K. Barnes, R. Davis, P. Knowles, N. Shorrocks

Proceedings Volume 9881, 988117 (2016) https://doi.org/10.1117/12.2229580

KEYWORDS: Infrared detectors, Satellites, Photovoltaics, Crystals, Infrared radiation, Photodiodes, Sensors, Reflectivity, Photoresistors, Diodes

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Proceedings Article | 8 November 2012 Paper

Status of IR detectors for high operating temperature produced by MOVPE growth of MCT on GaAs substrates

P. Knowles, L. Hipwood, N. Shorrocks, I. Baker, L. Pillans, P. Abbott, R. Ash, J. Harji

Proceedings Volume 8541, 854108 (2012) https://doi.org/10.1117/12.971431

KEYWORDS: Infrared detectors, Gallium arsenide, Temperature metrology, Medium wave, Sensors, Doping, Mercury cadmium telluride, Space operations, Etching, Infrared radiation

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Proceedings Article | 21 September 2012 Paper

A detector technology investigation for the Exoplanet Characterisation Observatory (EChO)

Enzo Pascale, Stuart Forder, Peter Knowles, Rashmi Sudiwala, Bruce Swinyard, Marcell Tessenyi

Proceedings Volume 8442, 84422Z (2012) https://doi.org/10.1117/12.927207

KEYWORDS: Sensors, Temperature metrology, Exoplanets, Optics manufacturing, Observatories, Resistance, Photoresistors, Mercury cadmium telluride, Optical testing, Cryogenics

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Proceedings Article | 31 May 2012 Paper

MWIR mercury cadmium telluride detectors for high operating temperatures

L. Pillans, R. Ash, L. Hipwood, P. Knowles

Proceedings Volume 8353, 83532W (2012) https://doi.org/10.1117/12.919015

KEYWORDS: Sensors, Imaging systems, Medium wave, Camera shutters, Infrared detectors, Nonuniformity corrections, Mid-IR, Mercury cadmium telluride, Thermography, Cameras

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Proceedings Article | 28 September 2011 Paper

MCT FPAs at high operating temperatures

P. Knowles, L. Hipwood, L. Pillans, R. Ash, P. Abbott

Proceedings Volume 8185, 818505 (2011) https://doi.org/10.1117/12.903042

KEYWORDS: Sensors, Medium wave, Temperature metrology, Diodes, Diffusion, Physics, Black bodies, Infrared technology, Resistance, Quantum efficiency

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Proceedings Article | 4 May 2010 Paper

Advances in dual-band IRFPAs made from HgCdTe grown by MOVPE

P. Abbott, L. Pillans, P. Knowles, R. McEwen

Proceedings Volume 7660, 766035 (2010) https://doi.org/10.1117/12.850099

KEYWORDS: Medium wave, Sensors, Image fusion, Mercury cadmium telluride, Infrared detectors, Gallium arsenide, Image resolution, Infrared radiation, Sensor performance, Fiber optic gyroscopes

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Proceedings Article | 7 May 2009 Paper

LW Hawk: a 16 µm pitch full-TV LW IRFPA made from HgCdTe grown by MOVPE

L. Hipwood, C. Jones, J. Price, M. Wilson, C. Maxey, J. Fitzmaurice, P. Knowles

Proceedings Volume 7298, 729820 (2009) https://doi.org/10.1117/12.817816

KEYWORDS: Sensors, Diodes, Mercury cadmium telluride, Gallium arsenide, Long wavelength infrared, Dry etching, Etching, Semiconducting wafers, Temperature metrology, Black bodies

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Proceedings Article | 7 May 2009 Paper

VLW IRFPAs made from HgCdTe grown by MOVPE

L. Hipwood, C. Jones, C. Maxey, D. Walker, J. Fitzmaurice, P. Abbott, N. Shorrocks, P. Knowles

Proceedings Volume 7298, 729822 (2009) https://doi.org/10.1117/12.817817

KEYWORDS: Diodes, Mercury cadmium telluride, Resistance, Sensors, Gallium arsenide, Diffusion, Heterojunctions, Readout integrated circuits, Electrons, Long wavelength infrared

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Proceedings Article | 9 October 2008 Paper

Recent developments in very long wave and shortwave infrared detection for space applications

Andrew Ashcroft, Chris Jones, Les Hipwood, Ian Baker, Peter Thorne, Nick Shorrocks, Peter Knowles, Harald Weller

Proceedings Volume 7106, 71061I (2008) https://doi.org/10.1117/12.800099

KEYWORDS: Diodes, Sensors, Avalanche photodetectors, Amplifiers, Readout integrated circuits, Resistance, Photodiodes, Capacitance, Thermography, Signal to noise ratio

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Proceedings Article | 2 October 2008 Paper

Results from the UK 3rd generation programme: Albion

R. K. McEwen, C. Axcell, P. Knowles, K. Hoade, M. Wilson, P. Dennis, P. Backhouse, N. Gordon

Proceedings Volume 7113, 71130G (2008) https://doi.org/10.1117/12.802343

KEYWORDS: Sensors, Long wavelength infrared, Mid-IR, Thermography, Cameras, Imaging systems, Readout integrated circuits, Infrared detectors, Silicon, Infrared radiation

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Proceedings Article | 5 May 2008 Paper

Dual-band MW/LW IRFPAs made from HgCdTe grown by MOVPE

J. Price, C. Jones, L. Hipwood, C. Shaw, P. Abbot, C. Maxey, H. W. Lau, J. Fitzmaurice, R. Catchpole, M. Ordish, P. Thorne, H. Weller, R. Mistry, K. Hoade, A. Bradford, D. Owton, P. Knowles

Proceedings Volume 6940, 69402S (2008) https://doi.org/10.1117/12.784483

KEYWORDS: Medium wave, Sensors, Mercury cadmium telluride, Diodes, Readout integrated circuits, Semiconducting wafers, Staring arrays, Infrared imaging, Gallium arsenide, Infrared radiation

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Proceedings Article | 15 April 2008 Paper

LW IRFPAs made from HgCdTe grown by MOVPE for use in multispectral imaging

L. Hipwood, I. Baker, C. Jones, C. Maxey, H. W. Lau, J. Fitzmaurice, M. Wilson, P. Knowles

Proceedings Volume 6940, 69400G (2008) https://doi.org/10.1117/12.780233

KEYWORDS: Sensors, Diodes, Stray light, Mercury cadmium telluride, Optical filters, Long wavelength infrared, Multispectral imaging, Resistance, Gallium arsenide, Imaging systems

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Proceedings Article | 14 May 2007 Paper

Albion: the UK 3rd generation high-performance thermal imaging programme

R. McEwen, M. Lupton, M. Lawrence, P. Knowles, M. Wilson, P. Dennis, N. Gordon, D. Lees, J. Parsons

Proceedings Volume 6542, 654214 (2007) https://doi.org/10.1117/12.718612

KEYWORDS: Sensors, Long wavelength infrared, Thermography, Mid-IR, Readout integrated circuits, Imaging systems, Silicon, Nonuniformity corrections, Diodes, Image sensors

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Proceedings Article | 14 May 2007 Paper

Affordable high-performance LW IRFPAs made from HgCdTe grown by MOVPE

L. Hipwood, C. Jones, D. Walker, C. Shaw, P. Abbott, R. Catchpole, M. Ordish, C. Maxey, H. Lau, P. Knowles, M. Wilson

Proceedings Volume 6542, 65420I (2007) https://doi.org/10.1117/12.720647

KEYWORDS: Diodes, Semiconducting wafers, Mercury cadmium telluride, Doping, Readout integrated circuits, Gallium arsenide, Cameras, Silicon, Heterojunctions, Diffusion

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Proceedings Article | 14 May 2007 Paper

Multi-color IRFPAs made from HgCdTe grown by MOVPE

C. Jones, L. Hipwood, J. Price, C. Shaw, P. Abbott, C. Maxey, H. Lau, R. Catchpole, M. Ordish, P. Knowles, N. Gordon

Proceedings Volume 6542, 654210 (2007) https://doi.org/10.1117/12.720645

KEYWORDS: Medium wave, Mercury cadmium telluride, Sensors, Doping, Staring arrays, Diodes, Readout integrated circuits, Arsenic, Infrared detectors, Cadmium

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Proceedings Article | 5 October 2006 Paper

Albion: cost-effective 3rd generation high-performance thermal imaging in the UK

R. McEwen, M. Lupton, M. Lawrence, P. Knowles, M. Wilson, P. Dennis, N. Gordon, D. Lees, J. Parsons

Proceedings Volume 6395, 63950G (2006) https://doi.org/10.1117/12.692338

KEYWORDS: Sensors, Long wavelength infrared, Thermography, Mid-IR, Readout integrated circuits, Imaging systems, Cameras, Diodes, Image sensors, Silicon

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Proceedings Article | 23 January 2003 Paper

Large-format MWIR focal plane arrays

Tim Ashley, Ronald Ballingall, John Beale, Ian Blenkinsop, Theresa Burke, Jim Firkins, David Hall, Leslie Hipwood, Colin Hollier, Peter Knowles, David Lees, J. Chris Little, Chris Shaw

Proceedings Volume 4820, (2003) https://doi.org/10.1117/12.451971

KEYWORDS: Sensors, Diodes, Staring arrays, Readout integrated circuits, Mid-IR, Silicon, Imaging systems, Indium, Imaging arrays, Doping

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Proceedings Article | 23 January 2003 Paper

High-performance thermal imaging for the 21st century

David Clarke, Peter Knowles

Proceedings Volume 4820, (2003) https://doi.org/10.1117/12.451994

KEYWORDS: Sensors, Signal processing, Calibration, Video, Imaging systems, Thermography, Avionic systems, Electronics, Image processing, Medium wave

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Proceedings Article | 17 July 2000 Paper

InSb focal plane array (FPAs) grown by molecular beam epitaxy (MBE)

Tim Ashley, Ian Baker, Theresa Burke, David Dutton, John Haigh, Leslie Hipwood, Richard Jefferies, Alan Johnson, Peter Knowles, J. Chris Little

Proceedings Volume 4028, (2000) https://doi.org/10.1117/12.391753

KEYWORDS: Sensors, Staring arrays, Doping, Semiconducting wafers, Diodes, Tellurium, Molecular beam epitaxy, Absorption, External quantum efficiency, Infrared detectors

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Proceedings Article | 24 June 1993 Paper

Laser damage in electron-beam-patterned surface resonant structures

Keith Lewis, Colin Brewitt-Taylor, Andrew Pitt, Jonathan Milward, T. Wyatt-Davies, Susan Jacobson, Peter Knowles

Proceedings Volume 1848, (1993) https://doi.org/10.1117/12.147399

KEYWORDS: Laser induced damage, Absorption, Dielectrics, Antennas, Metals, Laser damage threshold, Silicon, Chemical elements, Refractive index, Antireflective coatings

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Surface resonant structures can be used as spectral filtering elements. Both band-stop and band-pass designs are possible using capacitive and inductive mesh concepts respectively. With the current evolution in electron lithographic technology to allow the realisation of sub-micron features, it has become possible in recent years to produce resonant mesh arrays to high degrees of fidelity and performance over significant areas of optical substrates. These can provide, for example, responses in the infra-red spectral region using elements with a dimensional scale of a few microns. The unit cell design in the mesh can be relatively complex and can be tailored to provide specific spectral responses in the waveband range of interest. Such structures can find a wide variety of applications, especially as dichroic beam splitter elements for the separation of infra-red and RF radiation. The possibility of using such structures for spectral filtering has been known for many years, particularly for the microwave, millimeter and far infra-red wavelength regime. Some of the earlier applications in the far JR have been discussed by UJriCh [1,21 More recently, Byrne et al [31 fabricated capacitive and inductive mesh filters for the infra-red using electron beam lithography and demonstrated the bandstop and bandpass transmissive properties achievable. Byrne and coworkers used a lift-off technique to create capacitive mesh patterns having linewidths of less than O.25j.tm in O.lp.m thick aluminium and gold on calcium fluoride. Crossed capacitive dipoles of aluminium 2.6.tm in length with an aspect ratio of 10:1 produced a broad reflection band at 6.25tm. The measured bandwidth (FWHM) was about 2.5pm. For inductive designs, a two level lift-off approach was adopted, involving pattern transfer from an initial capacitive design using oxygen reactive ion etch techniques. A 1.8pm length slot with aspect ratio of 10:1 produced a resonance at 6.5.tm with peak transmittance of about 80% and bandwidth of 2.75p.m. Low levels of intrinsic absorption in the slot material of the inductive mesh are enhanced by the resonant effect of the mesh and reduce the level of transmittance achievable. It is of interest from the point of view of potential high power laser applications to explore the relationship between the level of optical absorbance and the ensuing laser damage threshold of such meshes. Mohebi [71 explored the response of wire grid polarisers to pulsed C02 laser irradiation at 10.6j.m and found that damage thresholds were largest for the case when the polarisation of the incident radiation was perpendicular to the wires. Antirerfiection coatings reduced the damage threshold. This work assesses the case of crossed dipole meshes and explores the role of absorption by incorporating weakly absorbing films in the meshes and by the addition of dielectric material between the absorber and the antenna plane. It also explores the role of resistive loss in determining the properties of capacitive meshes. The absorber used has optical constants of n = 2.9 - 0.25i which are typical of some transition metal oxides and chalcogenide materials.

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