Dr. Alan Hoffman Profile

Dr. Alan Hoffman

Chief Scientist

SPIE Involvement:

Author

Publications (33)

Proceedings Article | 17 September 2011 Paper

Evolution of large format impurity band conductor focal plane arrays for astronomy applications

Robert Mills, Eric Beuville, Elizabeth Corrales, Alan Hoffman, Gert Finger, Derek Ives

Proceedings Volume 8154, 81540R (2011) https://doi.org/10.1117/12.897292

KEYWORDS: Sensors, Astronomy, Space telescopes, James Webb Space Telescope, Telescopes, Quantum efficiency, Readout integrated circuits, Staring arrays, Mid-IR, Packaging

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Proceedings Article | 18 July 2008 Paper

Design of a 1k pixel Ge:Sb focal-plane array for far-IR astronomy

Jam Farhoomand, David Sisson, Jeffrey Beeman, Robert McMurray, Alan Hoffman, Brian Starr, Charles Rabkin, Joseph Sienicki, Elisabeth Corrales

Proceedings Volume 7020, 70200D (2008) https://doi.org/10.1117/12.789506

KEYWORDS: Sensors, Staring arrays, Far infrared, Photoresistors, Germanium, Astronomy, Cryogenics, Silicon, Infrared telescopes, Indium

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Proceedings Article | 26 September 2007 Paper

VIS/SWIR focal plane and detector development at Raytheon: instruments performance data and future developments at Raytheon

Jonathan Getty, Ellie Hadjiyska, David Acton, Sean Harris, Brian Starr, Alan Levy, Justin Wehner, Scott Taylor, Alan Hoffman

Proceedings Volume 6660, 66600C (2007) https://doi.org/10.1117/12.735905

KEYWORDS: Sensors, Mercury cadmium telluride, Short wave infrared radiation, Indium gallium arsenide, Readout integrated circuits, Quantum efficiency, Staring arrays, Diodes, Astronomy, Detector development

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Proceedings Article | 7 September 2006 Paper

A 32x32 CTIA readout design for deep cryogenic applications

Jam Farhoomand, Lunming Yuen, Alan Hoffman, Nancy Lum, Larry Lum, Erick Young

Proceedings Volume 6297, 629711 (2006) https://doi.org/10.1117/12.685278

KEYWORDS: Sensors, Field effect transistors, Far infrared, Cryogenics, Infrared sensors, Infrared detectors, Amplifiers, Multiplexers, Detector arrays, Optical instrument design

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Proceedings Article | 15 June 2006 Paper

1024 x 1024 Si:As IBC detector arrays for mid-IR astronomy

Peter Love, Eric Beuville, Elizabeth Corrales, John Drab, Alan Hoffman, Roger Holcombe, Nancy Lum

Proceedings Volume 6276, 62761Y (2006) https://doi.org/10.1117/12.684504

KEYWORDS: Sensors, Readout integrated circuits, Astronomy, James Webb Space Telescope, Quantum efficiency, Mid-IR, Semiconducting wafers, Detector arrays, Infrared radiation, Coating

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Proceedings Article | 15 June 2006 Paper

Large infrared and visible arrays for low background applications: an overview of current developments at Raytheon

Alan Hoffman, Peter Love, Elizabeth Corrales, Roger Holcombe

Proceedings Volume 6276, 62760Y (2006) https://doi.org/10.1117/12.684502

KEYWORDS: Sensors, Mercury cadmium telluride, Quantum efficiency, Silicon, Visible radiation, Short wave infrared radiation, Detector arrays, Astronomy, Infrared radiation, Mid-IR

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Proceedings Article | 25 August 2005 Paper

1024 x 1024 Si:As IBC detector arrays for JWST MIRI

Peter Love, Alan Hoffman, Nancy Lum, Ken Ando, Joe Rosbeck, William Ritchie, Neil Therrien, Roger Holcombe, Elizabeth Corrales

Proceedings Volume 5902, 590209 (2005) https://doi.org/10.1117/12.623473

KEYWORDS: Sensors, James Webb Space Telescope, Readout integrated circuits, Mid-IR, Quantum efficiency, Detector arrays, Silicon, Semiconducting wafers, Infrared radiation, Silicon carbide

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1K × 1K Si:As Impurity Band Conduction (IBC) arrays have been developed by RVS for the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). MIRI provides imaging, coronagraphy, and low and medium resolution spectroscopy over the 5 - 28 μm band. The IBC devices are also suitable for other low-background applications. The Si:As IBC detectors have a pixel dimension of 25 μm and respond to infrared radiation between 5 and 28 μm, covering an important Mid-IR region beyond the 1 - 5 μm range covered by the JWST NIRCam and NIRSpec instruments. Due to high terrestrial backgrounds at the longer Mid-IR wavelengths, it is very difficult to conduct ground-based observations at these wavelengths. Hence, the MIRI instrument on JWST can provide science not obtainable from the ground. We describe results of the development of a new 1024 × 1024 Si:As IBC array that responds with high quantum efficiency over the wavelength range 5 to 28 μm. The previous generation's largest, most sensitive infrared (IR) detectors at these wavelengths were the 256 × 256 / 30 μm pitch Si:As IBC devices built by Raytheon for the SIRTF/IRAC instrument¹. Detector performance results will be discussed, including relative spectral response, Responsive Quantum Efficiency (RQE) vs. detector bias, and dark current versus temperature. In addition, Sensor Chip Assembly (SCA) data will be presented from the first Engineering SCAs. The detector ROIC utilizes a PMOS Source Follower per Detector (SFD) input circuit with a well capacity of about 2 × 105 electrons. The read noise of the "bare" MUX is less than 12 e- rms with Fowler-8 sampling at an operating temperature of 7 K. A companion paper by Craig McMurtry (University of Rochester) will discuss the details of SB305 MUX noise measurements². Other features of the IBC array include 4 video outputs and a separate reference output with a frame rate of 0.36 Hz (2.75 sec frame time). Power dissipation is about 0.5 mW at a 0.36 Hz frame rate. Reset modes include both global reset and reset by row (ripple mode). Reference pixels are built-in to the output data stream. The 1K × 1K IBC is packaged in a robust modular package that consists of a multilayer motherboard, SiC pedestal, and cable assembly with 51-pin MDM connector. All materials of construction were chosen to match the thermal expansion coefficient of Silicon to provide excellent module thermal cycle reliability for cycling between room temperature and 7 K.

Proceedings Article | 31 May 2005 Paper

Megapixel InGaAs arrays for low background applications

Alan Hoffman, Todd Sessler, Joseph Rosbeck, David Acton, Martin Ettenberg

Proceedings Volume 5783, (2005) https://doi.org/10.1117/12.607635

KEYWORDS: Sensors, Indium gallium arsenide, Readout integrated circuits, Astronomy, Data modeling, Quantum efficiency, Short wave infrared radiation, Cameras, Amplifiers, Electrons

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Proceedings Article | 29 September 2004 Paper

2K X 2K InSb for astronomy

Alan Hoffman, Elizabeth Corrales, Peter Love, Joseph Rosbeck, Michael Merrill, Albert Fowler, Craig McMurtry

Proceedings Volume 5499, (2004) https://doi.org/10.1117/12.555200

KEYWORDS: Sensors, Astronomy, Quantum efficiency, Staring arrays, Manufacturing, Semiconducting wafers, James Webb Space Telescope, Detector arrays, Infrared radiation, Astronomical imaging

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Proceedings Article | 29 September 2004 Paper

1K X 1K Si:As IBC detector arrays for JWST MIRI and other applications

Peter Love, Alan Hoffman, Nancy Lum, Ken Ando, William Ritchie, Neil Therrien, Andrew Toth, Roger Holcombe

Proceedings Volume 5499, (2004) https://doi.org/10.1117/12.555219

KEYWORDS: Sensors, James Webb Space Telescope, Readout integrated circuits, Silicon carbide, Mid-IR, Quantum efficiency, Silicon, Semiconducting wafers, Space telescopes, Wafer testing

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1K × 1K Si:As Impurity Band Conduction (IBC) arrays have been developed by Raytheon Vision Systems (RVS) for the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). The devices are also suitable for other low-background applications. The Si:As IBC detectors respond out to ~28 microns, covering an important mid-IR region beyond the 1-5 micron range covered by the JWST NIRCam and NIRSpec instruments. Due to high terrestrial backgrounds at the longer mid-IR wavelengths, it is very difficult to conduct ground-based observations at these wavelengths. Hence, the MIRI instrument on JWST can provide science not obtainable from the ground. A mid-infrared instrument aboard a cryogenic space telescope can have an enormous impact in resolving key questions in astronomy and cosmology. The greatly reduced thermal backgrounds achievable on a space platform (compared to airborne or ground-based platforms) allow for more sensitive observations of dusty young galaxies at high redshifts, star formation of solar-type stars in the local universe, and formation and evolution of planetary disks and systems. We describe results of the development of a new 1024 × 1024 Si:As IBC array with 25-micron pixels that responds with high quantum efficiency over the wavelength range 5 to 28 microns. The previous generation's largest, most sensitive IR detectors at these wavelengths were the 256 × 256/30-micron pitch Si:As IBC devices built by Raytheon for the SIRTF/IRAC instrument. JWST MIRI detector requirements will be reviewed and some model results for IBC device performance will be presented. The IBC detector architecture will be described and the SB305 Readout Integrated Circuit (ROIC), developed specifically for JWST MIRI, will be discussed. The SB305 ROIC utilizes a PMOS Source Follower per Detector (SFD) input circuit with a well capacity of about 2 × 10⁵ electrons. The read noise is expected to be less than 20 e- rms with Fowler-8 sampling at an operating temperature of 7 K. Other features of the IBC array include 4 video outputs and a separate reference output with a frame rate of 0.37 Hz (2.7 sec frame time). Power dissipation is less than 0.5 mW at a 0.37 Hz frame rate. Reset modes include both global reset and reset by row (ripple mode). Reference pixels are built-in to the output data stream. The 1K × 1K IBC is packaged in a robust modular package that consists of a multilayer motherboard, silicon carbide (SiC) pedestal, and cable assembly with 51-pin MDM connectors. All materials of construction were chosen to match the thermal expansion coefficient of silicon to provide excellent module thermal cycle reliability for cycling between room temperature and 7 K.

Proceedings Article | 29 September 2004 Paper

Mosaic packaging for large-format infrared devices

Roger Holcombe, Alan Hoffman, Peter Love

Proceedings Volume 5499, (2004) https://doi.org/10.1117/12.555228

KEYWORDS: Sensors, Staring arrays, Packaging, Infrared astronomy, Astronomy, James Webb Space Telescope, Infrared telescopes, Infrared radiation, Detector arrays, Thermography

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Proceedings Article | 29 September 2004 Paper

Large infrared and visible arrays for low-background applications: an overview of current developments at Raytheon

Alan Hoffman, Peter Love, Ken Ando, Elizabeth Corrales

Proceedings Volume 5499, (2004) https://doi.org/10.1117/12.555159

KEYWORDS: Sensors, Quantum efficiency, Mercury cadmium telluride, Silicon, Detector arrays, Astronomy, Indium gallium arsenide, Infrared radiation, Short wave infrared radiation, Infrared detectors

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Proceedings Article | 29 September 2004 Paper

2K X 2K HgCdTe detector arrays for VISTA and other applications

Peter Love, Alan Hoffman, Ken Ando, Elizabeth Corrales, William Ritchie, Neil Therrien, Joseph Rosbeck, Roger Holcombe, David Gulbransen

Proceedings Volume 5499, (2004) https://doi.org/10.1117/12.555225

KEYWORDS: Sensors, Quantum efficiency, Readout integrated circuits, Mercury cadmium telluride, Antireflective coatings, Near infrared, K band, Visible radiation, Astronomy, Short wave infrared radiation

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Proceedings Article | 12 January 2004 Paper

Megapixel detector arrays: visible to 28 µm

Alan Hoffman, Peter Love, Joseph Rosbeck

Proceedings Volume 5167, (2004) https://doi.org/10.1117/12.516509

KEYWORDS: Sensors, Mercury cadmium telluride, Quantum efficiency, Detector arrays, Astronomy, Silicon, James Webb Space Telescope, Mid-IR, Infrared radiation, Infrared detectors

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Proceedings Article | 12 January 2004 Paper

Large-format 0.85- to 2.5-um HgCdTe detector arrays for low-background applications

Peter Love, Alan Hoffman, David Gulbransen, Mark Murray, Ken Ando, Neil Therrien, Joseph Rosbeck, Roger Holcombe

Proceedings Volume 5167, (2004) https://doi.org/10.1117/12.506258

KEYWORDS: Sensors, Readout integrated circuits, Mercury cadmium telluride, Antireflective coatings, Near infrared, Electrons, Cadmium sulfide, Silicon, Quantum efficiency, Astronomy

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Proceedings Article | 10 October 2003 Paper

Development of Si:As impurity band conduction (IBC) detectors for mid-infrared applications

Ken Ando, Alan Hoffman, Peter Love, Andrew Toth, Conrad Anderson, George Chapman, Craig McCreight, Kimberly Ennico, Mark McKelvey, Robert McMurray

Proceedings Volume 5074, (2003) https://doi.org/10.1117/12.497017

KEYWORDS: Sensors, James Webb Space Telescope, Quantum efficiency, Field effect transistors, Multiplexers, Detector development, Mid-IR, Prototyping, Readout integrated circuits, Error control coding

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Proceedings Article | 7 March 2003 Paper

Megapixel and larger readouts and FPAs for visible and infrared astronomy

David Gulbransen, Peter Love, Mark Murray, Nancy Lum, Christopher Fletcher, Elizabeth Corrales, Robert Mills, Alan Hoffman, Ken Ando

Proceedings Volume 4841, (2003) https://doi.org/10.1117/12.459851

KEYWORDS: Sensors, Silicon, Mercury cadmium telluride, Astronomy, Staring arrays, Semiconducting wafers, Visible radiation, Infrared astronomy, Short wave infrared radiation, Readout integrated circuits

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Proceedings Article | 5 March 2003 Paper

Large format Si: As IBC array performance for NGST and future IR space telescope applications

Kimberly Ennico, Mark McKelvey, Craig McCreight, Robert McMurray, Roy Johnson, Alan Hoffman, Peter Love, Nancy Lum

Proceedings Volume 4850, (2003) https://doi.org/10.1117/12.461158

KEYWORDS: Sensors, Infrared telescopes, Infrared detectors, Capacitance, Quantum efficiency, Space telescopes, Multiplexers, Mid-IR, Infrared radiation, Cryogenics

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Proceedings Article | 5 March 2003 Paper

Development of 2k x 2k FPA InSb modules for the NGST mission

Alan Hoffman, Peter Love, Ken Ando, Joseph Rosbeck, Nancy Lum, Roger Holcombe, John Durkee, Craig McMurtry

Proceedings Volume 4850, (2003) https://doi.org/10.1117/12.461131

KEYWORDS: Sensors, Staring arrays, Astronomy, Near infrared, Quantum efficiency, Infrared radiation, Electronics, Space telescopes, Mercury cadmium telluride, Temperature metrology

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Proceedings Article | 16 November 2000 Paper

Si:As IBC array performance for SIRTF/IRAC

Robert McMurray, R. Johnson, Craig McCreight, Mark McKelvey, James Garnett, Alan Hoffman, Nancy Lum, W. Lum, Michael Smith, K. Sparkman, Andrew Toth, George Domingo, Danny Krebs, Murzy Jhabvala

Proceedings Volume 4131, (2000) https://doi.org/10.1117/12.406573

KEYWORDS: Sensors, Quantum efficiency, Interference (communication), Infrared radiation, Infrared cameras, Signal to noise ratio, Cryogenics, Infrared sensors, Detector arrays, Field effect transistors

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Proceedings Article | 16 November 2000 Paper

InSb arrays for IRAC (infrared array camera) on SIRTF (Space Infrared Telescope Facility)

Judith Pipher, William Forrest, William Glaccum, Robert Benson, Danny Krebs, Murzy Jhabvala, Joseph Rosbeck, Nancy Lum, W. Lum, James Garnett, Alan Hoffman, George Domingo, G. Mark Cushman, David Rapchun

Proceedings Volume 4131, (2000) https://doi.org/10.1117/12.406544

KEYWORDS: Sensors, Multiplexers, Staring arrays, Infrared cameras, Detector arrays, Infrared radiation, Infrared telescopes, Cameras, Infrared sensors, Quantum efficiency

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Proceedings Article | 28 August 1998 Paper

Yardstick integrated science instrument module concept for NGST

Richard Burg, Pierre Bely, Robert Woodruff, John MacKenty, Massimo Stiavelli, Stefano Casertano, Craig McCreight, Alan Hoffman

Proceedings Volume 3356, (1998) https://doi.org/10.1117/12.324532

KEYWORDS: Sensors, Cameras, Near infrared, Spectrometers, Space telescopes, Optical benches, Spectrographs, Mirrors, Optical filters, Telescopes

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Proceedings Article | 21 August 1998 Paper

Near IR arrays for ground-based and space-based astronomy

Alan Hoffman, Ken Ando, Arnold Estrada, James Garnett, Nancy Lum, Peter Love, Joseph Rosbeck, K. Sparkman, Albert Fowler, Judith Pipher, William Forrest

Proceedings Volume 3354, (1998) https://doi.org/10.1117/12.317271

KEYWORDS: Astronomy, Sensors, Infrared astronomy, Infrared radiation, Quantum efficiency, IRIS Consortium, Mercury cadmium telluride, Detector arrays, Aerospace engineering, Infrared imaging

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Proceedings Article | 21 August 1998 Paper

Si:As IBC IR focal plane arrays for ground-based and space-based astronomy

Arnold Estrada, George Domingo, James Garnett, Alan Hoffman, Nancy Lum, Peter Love, Steven Solomon, John Venzon, G. Chapman, K. Sparkman, Craig McCreight, Mark McKelvey, Robert McMurray, John Estrada, S. Zins, R. McHugh, R. Johnson

Proceedings Volume 3354, (1998) https://doi.org/10.1117/12.317220

KEYWORDS: Sensors, Astronomy, Staring arrays, Electrons, Infrared astronomy, Signal to noise ratio, Quantum efficiency, Detector arrays, Capacitors, Temperature metrology

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Proceedings Article | 22 October 1996 Paper

High-background longwave Si:As IBC 320x240 IR focal plane array

Steven Solomon, Alan Tribble, Nancy Lum, John Venzon, George Domingo, Alan Hoffman, Michael Smith

Proceedings Volume 2816, (1996) https://doi.org/10.1117/12.255163

KEYWORDS: Sensors, Electrons, Arsenic, Staring arrays, Quantum efficiency, Long wavelength infrared, Astronomy, Signal to noise ratio, Infrared astronomy, Infrared sensors

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Proceedings Article | 22 October 1996 Paper

ALADDIN: the 1024x1024 InSb array--design, description, and results

Albert Fowler, Ian Gatley, Paul McIntyre, Frederick Vrba, Alan Hoffman

Proceedings Volume 2816, (1996) https://doi.org/10.1117/12.255162

KEYWORDS: Sensors, Analog electronics, Logic, Transistors, Clocks, Astronomy, Observatories, Infrared radiation, Multiplexers, Silicon

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Proceedings Article | 26 June 1996 Paper

Development of high-speed IR sensor chip technologies

Michael Dahlin, Alan Hoffman, J. West, Roger West, J. Santana, S. Ortega, S. Byers, David Thiede, S. Bailey, E. Herrin, M. Levy, R. Parlato, N. Maassen

Proceedings Volume 2745, (1996) https://doi.org/10.1117/12.243537

KEYWORDS: Sensors, Mid-IR, Short wave infrared radiation, Cryogenics, Optical filters, Charge-coupled devices, Analog electronics, Semiconductor lasers, Silicon, Transmitters

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Proceedings Article | 6 June 1995 Paper

ALADDIN: the 1024 x 1024 InSb array test results

Albert Fowler, Julie Heynssens, Ian Gatley, Frederick Vrba, Harold Ables, Alan Hoffman, James Woolaway

Proceedings Volume 2475, (1995) https://doi.org/10.1117/12.211273

KEYWORDS: Sensors, Clocks, Astronomy, Observatories, Logic, Quantum efficiency, Yield improvement, Astronomical imaging, Observational astronomy, Telescopes

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Proceedings Article | 14 September 1994 Paper

Next generation in very large InSb arrays: ALADDIN, the 1024x1024 InSb focal plane array readout evaluation results

Albert Fowler, Daniel Bass, Julie Heynssens, Ian Gatley, Frederick Vrba, Harold Ables, Alan Hoffman, Michael Smith, James Woolaway

Proceedings Volume 2268, (1994) https://doi.org/10.1117/12.185844

KEYWORDS: Semiconducting wafers, Staring arrays, Sensors, Cryogenics, Astronomy, Silicon, Observatories, Multiplexers, Infrared radiation, Infrared detectors

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Proceedings Article | 1 June 1994 Paper

Next generation in InSb arrays: ALADDIN--the 1024x1024 InSb focal plane array development project status report

Albert Fowler, Ian Gatley, Frederick Vrba, Harold Ables, Alan Hoffman, James Woolaway

Proceedings Volume 2198, (1994) https://doi.org/10.1117/12.176770

KEYWORDS: Sensors, Semiconducting wafers, Staring arrays, Infrared radiation, Wafer testing, Clocks, Astronomy, Indium, Infrared detectors, Infrared telescopes

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Proceedings Article | 20 October 1993 Paper

Current and future InSb infrared arrays for astronomy

Alan Hoffman

Proceedings Volume 1946, (1993) https://doi.org/10.1117/12.158669

KEYWORDS: Astronomy, Infrared astronomy, Infrared radiation, Infrared detectors, Sensors, Electrons, Detector arrays, Staring arrays, Manufacturing, Infrared technology

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Proceedings Article | 1 July 1992 Paper

Low-noise 256 x 256 10-kelvin staring FPA

Nancy Lum, James Asbrock, Rebekah White, Frank Augustine, A. Hoffman, Sven Nystrom

Proceedings Volume 1684, (1992) https://doi.org/10.1117/12.60494

KEYWORDS: Staring arrays, Standards development, Astronomy, Infrared radiation, Amplifiers, Electrons, Infrared cameras, Silicon, Interference (communication), CMOS technology

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Proceedings Article | 1 December 1991 Paper

High-performance 256 x 256 InSb FPA for astronomy

Alan Hoffman, David Randall

Proceedings Volume 1540, (1991) https://doi.org/10.1117/12.48749

KEYWORDS: Sensors, Staring arrays, Astronomy, Multiplexers, Stellar astronomy, Infrared imaging, Infrared radiation, Quantum efficiency, Telescopes, Infrared telescopes

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Showing 5 of 33 publications

Conference Committee Involvement (2)

High Energy, Optical, and Infrared Detectors for Astronomy II

24 May 2006 | Orlando, Florida , United States

Optical and Infrared Detectors for Astronomy

21 June 2004 | Glasgow, United Kingdom

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