Prof. Christopher K. Walker Profile

Prof. Christopher K. Walker

Professor of Astronomy at Steward Observatory

SPIE Involvement:

Author

Publications (68)

SPIE Journal Paper | 20 December 2024

Fourteen-meter aperture deployable off-axis far-infrared space telescope design for SALTUS observatory

Daewook Kim, Youngsik Kim, Heejoo Choi, Marcos Esparza, Oliver Wu, Tianyao Zhang, Yuzuru Takashima, Arthur Palisoc, Christopher Walker

JATIS, Vol. 10, Issue 04, 042309, (December 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.4.042309

KEYWORDS: Mirror surfaces, Wavefront errors, Design, Optical surfaces, Mirrors, Space telescopes, Optical design, Tolerancing, Observatories, Equipment

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SPIE Journal Paper | 19 December 2024 Open Access

Single Aperture Large Telescope for Universe Studies: science overview

Gordon Chin, Carrie Anderson, Jennifer Bergner, Nicolas Biver, Gordon Bjoraker, Thibault Cavalie, Michael DiSanti, Jian-Rong Gao, Paul Hartogh, Leon Harding, Qing Hu, Daewook Kim, Craig Kulesa, Gert de Lange, David Leisawitz, Rebecca Levy, Arthur Lichtenberger, Daniel Marrone, Joan Najita, Trent Newswander, George Rieke, Dimitra Rigopoulou, Peter Roelfsema, Nathan Roth, Kamber Schwarz, Yancy Shirley, Justin Spilker, Anthony Stark, Floris van der Tak, Yuzuru Takashima, Alexander Tielens, David Wilner, Edward Wollack, Stephen Yates, Erick Young, Christopher Walker

JATIS, Vol. 10, Issue 04, 042310, (December 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.4.042310

KEYWORDS: Galactic astronomy, Observatories, Stars, Large telescopes, James Webb Space Telescope, Equipment, Spatial resolution, Planets, Spectral resolution, Carbon monoxide

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SPIE Journal Paper | 14 December 2024

High-Resolution Receiver for the Single Aperture Large Telescope for Universe Studies

Jose Silva, Christopher Walker, Craig Kulesa, Abram Young, Jian-Rong Gao, Qing Hu, Jeffrey Hesler, Anders Emrich, Paul Hartogh, Wouter Laauwen, Gert de Lange, Peter Rolfsema

JATIS, Vol. 10, Issue 04, 042308, (December 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.4.042308

KEYWORDS: Quantum receivers, Equipment, Quantum cascade lasers, Terahertz radiation, Spectrometers, Receivers, Large telescopes, Heterodyning, Spectral resolution, Signal processing

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SPIE Journal Paper | 15 November 2024 Open Access

Star and planet formation with the Single Aperture Large Telescope for Universe Studies space observatory

Kamber Schwarz, Alexander Tielens, Joan Najita, Jennifer Bergner, Quentin Kral, Carrie Anderson, Gordon Chin, David Leisawitz, David Wilner, Peter Roelfsema, Floris van der Tak, Erick Young, Chris Walker

JATIS, Vol. 10, Issue 04, 042307, (November 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.4.042307

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SPIE Journal Paper | 13 September 2024

Milky Way and nearby galaxy science with the SALTUS space observatory

Rebecca Levy, Alexander Tielens, Justin Spilker, Daniel Marrone, Desika Narayanan, Christopher Walker

JATIS, Vol. 10, Issue 04, 042304, (September 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.4.042304

KEYWORDS: Galactic astronomy, Stars, Medium wave, Spatial resolution, James Webb Space Telescope, Diagnostics, Carbon monoxide, Equipment, Clouds, Observatories

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SPIE Journal Paper | 9 September 2024 Open Access

Design, implementation, and performance of the primary reflector for SALTUS

Jonathan Arenberg, Leon Harding, Bob Chang, Steve Kuehn, Dave Oberg, Michaela Villarreal, Arthur Palisoc, Christopher Walker, Daewook Kim, Zach Lung, Dave Lung

JATIS, Vol. 10, Issue 04, 042306, (September 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.4.042306

KEYWORDS: Reflectors, Design, Particles, Data modeling, Tolerancing, Optical surfaces, Space operations, Solar processes, Manufacturing, Contamination

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SPIE Journal Paper | 4 September 2024 Open Access

Solar system science with the Single Aperture Large Telescope for Universe Studies space observatory

Carrie Anderson, Nicolas Biver, Gordon Bjoraker, Thibault Cavalié, Gordon Chin, Michael DiSanti, Paul Hartogh, Nathan Roth, Alexander Tielens, Christopher Walker

JATIS, Vol. 10, Issue 04, 042302, (September 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.4.042302

KEYWORDS: Ice, Solar system, Comets, Atmospheres, Planets, Large telescopes, Venus, Jupiter, Spectral resolution, Saturn

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Single Aperture Large Telescope for Universe Studies (SALTUS) is a NASA Astrophysics Probe Explorer (APEX)-class mission concept employing a robust far-infrared pointed space observatory. SALTUS comprises a 14-m inflatable reflector that provides 16× the sensitivity and 4× the angular resolution of Herschel, with a sunshield that radiatively cools the primary to 45 K, along with cryogenic detectors that collectively span the 34 to 660 μm far-infrared spectral range at high and moderate spectral resolutions. The high sensitivity and high spectral resolving power of the SALTUS heterodyne receivers enable both submillimeter and far-infrared observations of trace compounds comprising water and its isotopologues, hydrogen deuteride (HD), and a plethora of molecular species containing carbon, hydrogen, nitrogen, oxygen, phosphorus, or sulfur (CHNOPS), all of which are obscured by the Earth’s atmosphere. The high sensitivity and broadband spectral coverage of the SALTUS far-infrared grating spectrometer enables far-infrared observations of the lattice vibrational spectral signatures of ices and mineral grains contained within a wide variety of solar system targets, including comets, planetary atmospheres, near Enceladus’ plumes, and on the surfaces of icy moons, Jupiter trojans, centaurs, and Kuiper Belt objects. A key objective of SALTUS is to measure HDO/H2O in both Jupiter family and Oort cloud comets. Additional observations will allow us to characterize the water torus around Saturn generated by its icy moon Enceladus, determine the source of stratospheric water in the giant planets, ascertain the time evolution of water on Venus, and search for H2O plumes on Europa, Ganymede, and Callisto. SALTUS will measure HD/H2 in all four giant planets to constrain models of their origin. SALTUS can also measure the abundance of CHNOPS-containing molecules and halides in the atmosphere of Venus and in the comae of comets. We review the extensive amount of solar system science achievable with SALTUS for both the Guaranteed Time Observation and the Guest Observer APEX mission observing programs.

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Proceedings Article | 24 August 2024 Presentation

Single aperture large telescope for universe studies (SALTUS)

Christopher Walker, Jonathan Arenberg, Yuzuru Takashima, Daewook Kim, Daniel Marrone, Gordon Chin, Carrie Anderson, Craig Kulesa, Leon Harding, Peter Roelfsema, Trent Newswander

Proceedings Volume 13092, 130920E (2024) https://doi.org/10.1117/12.3020502

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Proceedings Article | 24 August 2024 Presentation

SAFARI-lite on SALTUS: taking FarIR spectroscopy of the obscured universe to the next level

Peter Roelfsema, Gert de Lange, Wouter Laauwen, Stephen Yates, Jose Silva, Jian-Rong Gao, Floris van der Tak, Erik van der Meer, Ramon Navarro, Jean-Marc Duval, Carole Tucker, Jochem Baselmans, Chris Walker

Proceedings Volume 13092, 130920F (2024) https://doi.org/10.1117/12.3020485

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Proceedings Article | 24 August 2024 Poster

SALTUS space observatory architecture

Jonathan Arenberg, Christopher Walker, Daewook Kim, Leon Harding, Benjamin Donovan, David Oberg, Ryan Goold

Proceedings Volume 13092, 130923C (2024) https://doi.org/10.1117/12.3020441

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SPIE Journal Paper | 22 August 2024 Open Access

SALTUS probe class space mission: observatory architecture and mission design

Leon Harding, Jonathan Arenberg, Benjamin Donovan, Dave Oberg, Ryan Goold, Bob Chang, Christopher Walker, Dana Turse, Jim Moore, Jim Pearson, John Kidd, Zach Lung, Dave Lung

JATIS, Vol. 10, Issue 04, 042303, (August 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.4.042303

KEYWORDS: Space operations, Observatories, Design, Data storage, Equipment, Cryogenics, James Webb Space Telescope, Reflectors, Control systems, Sun

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We describe the space observatory architecture and mission design of the Single Aperture Large Telescope for Universe Studies (SALTUS) mission, a National Aeronautics and Space Administration (NASA) Astrophysics Probe Explorer concept. SALTUS will address key far-infrared science using a 14-m diameter <45 K primary reflector (M1) and will provide unprecedented levels of spectral sensitivity for planet, solar system, and galactic evolution studies and cosmic origins. Drawing from Northrop Grumman’s extensive NASA mission heritage, the observatory flight system is based on the LEOStar-3 spacecraft platform to carry the SALTUS Payload. The Payload is comprised of the inflation control system, sunshield module (SM), cold corrector module (CCM), warm instrument electronics module, and primary reflector module (PRM). The 14-m M1 is an off-axis inflatable membrane radiatively cooled by a two-layer sunshield (∼1000 m2 per layer). The CCM corrects for residual aberration from M1 and delivers a focused beam to two instruments—the High-Resolution Receiver (HiRX) and SAFARI-Lite. The CCM and PRM reside atop a truss-based composite deck that also provides a platform for the attitude control system. The SALTUS 5-year mission lifetime is driven by a two-consumable architecture: the propellant system and the inflation control system. The core interface module (CIM), a multi-faceted composite truss structure, provides a load path with high stiffness, mechanical attachment, and thermal separation between the Payload and spacecraft. The SM attaches outside the CIM with its aft end integrating directly to the bus. The spacecraft maintains an attitude off M1’s boresight with respect to the Sun line to facilitate the <45 K thermal environment. SALTUS will reside in a Sun–Earth halo L2 orbit with a maximum Earth slant range of 1.8 million km, thereby reducing orbit transfer delta-v. The instantaneous field of regard provides two continuous 20 deg viewing zones around the ecliptic poles, resulting in full sky coverage in 6 months.

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SPIE Journal Paper | 20 August 2024

High-redshift extragalactic science with the Single Aperture Large Telescope for Universe Studies (SALTUS) space observatory

Justin Spilker, Rebecca Levy, Daniel Marrone, Stacey Alberts, Scott Chapman, Mark Dickinson, Eiichi Egami, Ryan Endsley, Desika Narayanan, George Rieke, Anthony Stark, Alexander Tielens, Christopher Walker

JATIS, Vol. 10, Issue 04, 042305, (August 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.4.042305

KEYWORDS: Galactic astronomy, James Webb Space Telescope, Stars, Spectroscopy, Mid infrared, Spatial resolution, Spectral resolution, Observatories, Diagnostics, Equipment

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Proceedings Article | 16 August 2024 Presentation + Paper

4×2 hot electron bolometer mixer arrays for detection at 1.4, 1.9, and 4.7 THz for a balloon borne terahertz observatory

J. R. Silva, W. Laauwen, B. Mirzaei, N. Vercruyssen, M. Finkel, M. Westerveld, N. More, V. Silva, A. Young, C. Kulesa, C. Walker, F. van der Tak, J. Gao

Proceedings Volume 13102, 131020I (2024) https://doi.org/10.1117/12.3019197

KEYWORDS: Terahertz radiation, Receivers, Detector arrays, Heterodyning, Quantum cascade lasers

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Proceedings Article | 31 August 2022 Presentation + Paper

Gal/Xgal U/LDB Spectroscopic/Stratospheric THz Observatory: GUSTO

Christopher Walker, Craig Kulesa, Abram Young, William Verts, Jian-Rong Gao, Qing Hu, Jose Silva, Behnam Mirzaei, Wouter Laauwen, Jeffrey Hesler, Christopher Groppi, Anders Emrich

Proceedings Volume 12190, 121900E (2022) https://doi.org/10.1117/12.2629051

KEYWORDS: Terahertz radiation, Telescopes, Quantum cascade lasers, Spectrometers, Receivers, Mirrors, Clouds, Beam splitters, Observatories

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Proceedings Article | 27 August 2022 Presentation + Paper

Orbiting astronomical satellite for investigating stellar systems (OASIS): a paradigm shift in realizing large space telescopes

Siddhartha Sirsi, Christopher Walker, Jonathan Arenberg, Yuzuru Takashima, Daewook Kim, Heejoo Choi, Arthur Palisoc, Henry Quach, Marcos Esparza, Kevin Derby, Luke Mayer, Tianyao Zhang, Aman Chandra, Anthony Stark

Proceedings Volume 12180, 121801Q (2022) https://doi.org/10.1117/12.2629100

KEYWORDS: Space telescopes, Receivers, Astronomy, Optical design, Satellites, Mirrors, Cryogenics, Space operations, Metrology, LIDAR

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SPIE Journal Paper | 16 August 2022 Open Access

Optical design of the Orbiting Astronomical Satellite for Investigating Stellar Systems

Siddhartha Sirsi, Yuzuru Takashima, Arthur Palisoc, Heejoo Choi, Jonathan Arenberg, Daewook Kim, Christopher Walker

JATIS, Vol. 8, Issue 03, 034002, (August 2022) https://doi.org/10.1117/12.10.1117/1.JATIS.8.3.034002

KEYWORDS: Mirrors, Optical design, Astronomy, Satellites, Reflectors, Receivers, Telescopes, Monochromatic aberrations, Space telescopes, Wavefronts

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Proceedings Article | 1 September 2021 Open Access

Mid-to-high frequency characterization of inflatable membrane optics

Heejoo Choi, Art Palisoc, Amarjiit Vikkas, Marcos Esparza, Joel Berkson, Yuzuru Takashima, Daewook Kim, Christopher Walker

Proceedings Volume 11820, 118200V (2021) https://doi.org/10.1117/12.2594412

KEYWORDS: Deflectometry, Optical testing, Optical fabrication, Interferometers, Spatial frequencies, Metrology, Mirrors, Telescopes

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Proceedings Article | 24 August 2021 Presentation + Paper

OASIS architecture: key features

Jonathan Arenberg, Michaela Villareal, Jud Yamane, Tony Yu, Justin Lazear, John Pohner, Mitchell Sangalis, Steven Jackson, Elisabeth Morse, Ryan Tyler, Pradipto Ghosh, Art Palisoc, Christopher Walker, Yuzuru Takashima, Daewook Kim, Siddhartha Sirsi, Aman Chandra

Proceedings Volume 11820, 118200S (2021) https://doi.org/10.1117/12.2594681

KEYWORDS: Observatories, Reflectors, Receivers, Space operations, Telescopes, Sun, Solar radiation models, Solar radiation, Mirrors, Bolometers

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Proceedings Article | 24 August 2021 Open Access

All reflective THz telescope design with an inflatable primary antenna for Orbiting Astronomical Satellite for Investigating Stellar Systems (OASIS) mission

Yuzuru Takashima, Siddhartha Sirsi, Heejoo Choi, Jonathan Arenberg, Daewook Kim, Christopher Walker

Proceedings Volume 11820, 118200P (2021) https://doi.org/10.1117/12.2594610

KEYWORDS: Antennas, Mirrors, Scanners, Reflectivity, Optical design, Terahertz radiation, Sensors, Geometrical optics, Astronomy, Aluminum

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Proceedings Article | 24 August 2021 Open Access

Stressed deformable reflector design and pneumatic membrane antenna for cryogenic thermal vacuum chamber testing

Marcos Esparza, Heejoo Choi, Hyukmo Kang, Christian d'Aubigny, Amarjiit Pandde, Henry Quach, Aman Chandra, Karlene Karrfalt, Yuzuru Takashima, Art Palisoc, Jonathan Arenberg, Kristy Gogick Marshall, Christopher Glynn, Sean Godinez, Marcos Tafoya, Brandon Chalifoux, Christopher Walker, Daewook Kim

Proceedings Volume 11820, 118200R (2021) https://doi.org/10.1117/12.2594403

KEYWORDS: Actuators, Reflectors, Computer aided design, Antennas, Prototyping, Polonium, Reflector design, Aluminum, Wavefronts, Solid modeling

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Proceedings Article | 24 August 2021 Open Access

Parametric design study of the Orbiting Astronomical Satellite for Investigating Stellar Systems (OASIS) space telescope

Siddhartha Sirsi, Yuzuru Takashima, Art Palisoc, Aman Chandra, Christopher Walker, Daewook Kim

Proceedings Volume 11820, 118200Q (2021) https://doi.org/10.1117/12.2594208

KEYWORDS: Mirrors, Reflectors, Zemax, Astronomy, Wavefronts, Satellites, Optical instrument design, Optical components, Space telescopes

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Proceedings Article | 24 August 2021 Open Access

Analytical and finite element analysis tool for nonlinear membrane antenna modeling for astronomical applications

Arthur Palisoc, Gerard Pardoen, Yuzuru Takashima, Aman Chandra, Siddharta Sirsi, Heejoo Choi, Daewook Kim, Henry Quach, Jonathan Arenberg, Christopher Walker

Proceedings Volume 11820, 118200U (2021) https://doi.org/10.1117/12.2594050

KEYWORDS: Reflectors, Finite element methods, James Webb Space Telescope, Telescopes, Mirrors, Antennas, Inverse problems

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The uninflated shape configurations of parabolic and spherical membrane mirrors were calculated by solving the inverse problem, i.e., given the design inflation pressure, the membrane material and geometric properties, what must be the initial uninflated shape such that on inflation to the design pressure, the exact desired surface of revolution is obtained. The resulting first order nonlinear differential equation was numerically integrated using the boundary conditions. The initial uninflated shape was then subjected to a forward transformation using FAIM, a proprietary geometric nonlinear membrane finite element code. FAIM has been validated against exact analytical solutions for both small and extremely large deformations that are up to eight orders of magnitude larger compared with the starting undeflected shape. Simulations reveal that to fabricate a very accurate and precise inflated membrane mirror relative to the design parameters, one must not only accurately measure and input the moduli in both meridional and hoop directions but an accurately measured Poisson’s ratio as well. The code was used to guide the membrane mirror design. For very small aperture diameters, the initial uninflated shape may be fabricated by thermo-forming the membrane. For aperture diameters exceeding one meter however, the membrane mirror is built with discrete gores that are joined together with tapes at the seams. This provided the impetus to write a companion computer code FLATE, to calculate the gore shapes using a slight modification of the solution to the inverse transformation equation to account for the presence of the seam tapes. After the gores were determined, the resulting final inflated shape was calculated and verified using FAIM. Sensitivity analyses can now be carried out to determine the resulting surface shape as a function of the different sources of error: gore width, gore length, perimeter attachment uncertainties, thermal effects, variation of material properties over the membrane continuum and inflation pressure changes. The code has been shown to be more robust than equivalent commercial analytical packages in so far as membrane, cable and space-frame element combinations are concerned. In particular, the analytical and finite element codes were used in the preliminary assessment of a membrane optic for the OASIS Mission (Orbiting Astronomical Satellite for Investigating Stellar Systems) [1]. The OASIS is a 20-meter class space observatory operating at high spectral resolution in the terahertz frequencies. Over its nominal 2-year mission it will probe conditions and search for biogenic molecules on hundreds of protoplanetary disks and other solar system objects.

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Proceedings Article | 24 August 2021 Open Access

Deflectometry-based thermal vacuum testing for a pneumatic terahertz antenna

Henry Quach, Marcos Esparza, Hyukmo Kang, Aman Chandra, Heejoo Choi, Joel Berkson, Karlene Karrfalt, Siddhartha Sirsi, Yuzuru Takashima, Art Palisoc, Jonathan Arenberg, Kristy Gogick Marshall, Christopher Glynn, Sean Godinez, Marcos Tafoya, Christopher Walker, Christian Drouet d'Aubigny, Daewook Kim

Proceedings Volume 11820, 118200W (2021) https://doi.org/10.1117/12.2594902

KEYWORDS: Deflectometry, Calibration, Cameras, Antennas, Metrology

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Proceedings Article | 24 August 2021 Open Access

Orbiting Astronomical Satellite for Investigating Stellar Systems (OASIS): following the water trail from the interstellar medium to oceans

Christopher Walker, Gordon Chin, Susanne Aalto, Carrie Anderson, Jonathan Arenberg, Cara Battersby, Edwin Bergin, Jenny Bergner, Nicolas Biver, Gordon Bjoraker, John Carr, Thibault Cavalié, Elvire De Beck, Michael DiSanti, Paul Hartogh, Leslie Hunt, Daewook Kim, Yuzuru Takashima, Craig Kulesa, David Leisawitz, Joan Najita, Dimitra Rigopoulou, Kamber Schwarz, Yancy Shirly, Antony Stark, Xander Tielens, Serena Viti, David Wilner, Edward Wollack, Erick Young

Proceedings Volume 11820, 118200O (2021) https://doi.org/10.1117/12.2594847

KEYWORDS: Galactic astronomy, Planets, Stars, Comets, Solar system, Clouds, Carbon monoxide, Spectral resolution, Spatial resolution, Terahertz radiation

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Proceedings Article | 13 December 2020 Poster

4.7 THz local oscillator multiplexer for GUSTO

Behnam Mirzaei, Matvey Finkel, J.R. Silva, Wouter Laauwen, Christopher Groppi, Ali Khalatpour, Qing Hu, Abram Young, Christopher Walker, Jian Rong Gao

Proceedings Volume 11453, 114533P (2020) https://doi.org/10.1117/12.2565778

KEYWORDS: Terahertz radiation, Oscillators, Multiplexers, Quantum cascade lasers, Terahertz spectroscopy, Spectroscopy, Observatories, Nitrogen, Carbon, Oxygen

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Proceedings Article | 20 August 2020 Presentation + Paper

Full-aperture optical metrology for inflatable membrane mirrors

Henry Quach, Joel Berkson, Siddhartha Sirsi, Heejoo Choi, Ruben Dominguez, Brian Duffy, David Lesser, Yuzuru Takashima, Art Palisoc, Christopher Walker, Dae Wook Kim

Proceedings Volume 11487, 114870N (2020) https://doi.org/10.1117/12.2569750

KEYWORDS: Deflectometry, Metrology, Reflectors, Photogrammetry, Telescopes

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Proceedings Article | 2 August 2018 Paper

IF system design for the Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO)

Marko Neric, Christopher Groppi, Hamdi Mani, Justin Mathewson, Kristina Davis, Matthew Underhill, Thomas Mozdzen, Craig Kulesa, Abram Young, Christopher Walker

Proceedings Volume 10708, 107082W (2018) https://doi.org/10.1117/12.2314096

KEYWORDS: Cryogenics, Flexible circuits, Terahertz radiation, Clouds, Amplifiers, Terahertz spectroscopy

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We present the design, and prototype phases of the intermediate frequency (IF) system for the upcoming balloon borne observatory, Galactic/Extragalactic Ultra-Long Duration Balloon (ULDB) Spectroscopic Terahertz Ob- servatory (GUSTO). GUSTO is a multi-organizational project whose goal is to address several key unanswered questions concerning all of the phases of the stellar life cycle within the Interstellar Medium (ISM). Using the NASA ULDB system for its platform, GUSTO will employ on-the-fly mapping techniques to scan a total of 124 square degrees of the Milky Way and Large Magellanic Cloud (LMC). GUSTO will survey the three brightest cooling lines in the Milky Way and the LMC. These lines are [CII], [OI], and [NII] corresponding to the three wavelengths of 158, 63, and 205 micron respectively. The completed survey will provide higher angular, and velocity resolution than that of previous surveys of [CII], [OI], and [NII]. These lines will be measured using three 8-pixel heterodyne arrays, each one dedicated to an individual cooling line, and all working together to make a 24-pixel focal plane. The GUSTO IF system is being designed to operate at low power consumption and high sensitivity all in a compact and lightweight package. The IF system will include a wideband 0.3 - 5 GHz, cryogenic, low noise amplifier (LNA), which will boost the IF output of a superconducting hot electron bolometer (HEB) mixer. The LNA was designed with commercial, off the shelf SiGe heterojunction bipolar transistors, and surface mount passive components. The LNA design has been optimized for low power consumption, and for sensitivity. The input impedance of the LNA is matched to the output impedance of the mixer over a wide range of frequencies to reduce reflections, and standing waves. Warm IF electronics have also been designed using commercial, off the shelf, surface mount SiGe transistors in order to achieve a high, and at gain (>50dB) over the entire bandwidth. These components provide variable gain and deliver an optimum signal level to the analog to digital converter of the backend spectrometer. The warm IF components were optimized for wide bandwidth, low power consumption, as well as reliability, and fit in a compact package. Commercially fabricated custom flexible printed circuit boards are being used for multi-channel stripline-based transmission lines, instead of the traditional stainless steel cryogenic semi-rigid coaxial cables. Replacing coaxial cables with the flexible printed circuit boards allows us to transmit through up to 16 lines on a single flex circuit, without losing performance, and furthering the design goal of providing a compact/lightweight solution. Each of the components used in this IF system will undergo rigorous qualification testing, and documentation in accordance with a NASA Class-D balloon mission. We discuss the design challenges in adapting cryogenic, and warm IF electronics to operate for an ultra long duration balloon mission.

Proceedings Article | 16 July 2018 Paper

SmallSat interferometry for THz astrophysics

Christopher Groppi, Paul Goldsmith, Philip Mauskopf, Jose Siles, Jonathan Hoh, Jeremy Whitton, Gena Pilyavsky, Christopher Walker, Adrian Tang

Proceedings Volume 10698, 1069832 (2018) https://doi.org/10.1117/12.2312822

KEYWORDS: Receivers, Satellites, Optical correlators, Terahertz radiation, Antennas, Telecommunications, Prototyping, Interferometry, Spherical lenses, Intelligence systems

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Proceedings Article | 9 July 2018 Presentation + Paper

4×2 HEB receiver at 4.7 THz for GUSTO

J. R. Silva, B. Mirzaei, W. Laauwen, N. More, A. Young, C. Kulesa, C. Walker, A. Khalatpour, Q. Hu, C. Groppi, J. Gao

Proceedings Volume 10708, 107080Z (2018) https://doi.org/10.1117/12.2313410

KEYWORDS: Terahertz radiation, Quantum cascade lasers, Receivers, Lenses, Antennas, Silicon, Observatories, Space telescopes, Optical simulations, Collimation

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Proceedings Article | 27 July 2016 Paper

Optical design for the large balloon reflector

German Cortes-Medellin, Stefan O'Dougherty, Christopher Walker, Paul Goldsmith, Chris Groppi, Steve Smith, Pietro Bernasconi

Proceedings Volume 9906, 99061Y (2016) https://doi.org/10.1117/12.2233861

KEYWORDS: Space telescopes, Telescopes, Reflectors, Optical design, Terahertz radiation, Spherical lenses, Tolerancing, Clouds, Astronomy, Solar system

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Proceedings Article | 20 July 2016 Paper

Results of using permanent magnets to suppress Josephson noise in the KAPPa SIS receiver

Caleb Wheeler, Marko Neric, Christopher Groppi, Matthew Underhill, Hamdi Mani, Sander Weinreb, Damon Russell, Jacob Kooi, Arthur Lichtenberger, Christopher Walker, Craig Kulesa

Proceedings Volume 9914, 99141W (2016) https://doi.org/10.1117/12.2231358

KEYWORDS: Magnetism, Receivers, Magnetic sensors, Sensors, Heterodyning, Solar concentrators, Neodymium, Superconductors, Tolerancing, Calibration

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Proceedings Article | 23 July 2014 Paper

A 4.7THz heterodyne receiver for a balloon borne telescope

D. Hayton, J. Kloosterman, Y. Ren, T. Kao, J. Gao, T. Klapwijk, Q. Hu, C. Walker, J. Reno

Proceedings Volume 9153, 91531R (2014) https://doi.org/10.1117/12.2055790

KEYWORDS: Terahertz radiation, Receivers, Quantum cascade lasers, Heterodyning, Telescopes, Gas lasers, Stars, Oscillators, Temperature metrology, Spectroscopy

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Proceedings Article | 23 July 2014 Paper

The kilopixel array pathfinder project (KAPPa), a 16-pixel integrated heterodyne focal plane array: characterization of the single pixel prototype

Caleb Wheeler, Christopher Groppi, Hamdi Mani, Patrick McGarey, Linda Kuenzi, Sander Weinreb, Damon Russell, Jacob Kooi, Arthur Lichtenberger, Christopher Walker, Craig Kulesa

Proceedings Volume 9153, 91530K (2014) https://doi.org/10.1117/12.2056606

KEYWORDS: Receivers, Sensors, Computing systems, Staring arrays, Prototyping, Terahertz radiation, Clouds, Control systems, Magnetism, Black bodies

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Proceedings Article | 23 July 2014 Paper

Methodology for a sub-millimeter near-field beam pattern measurement system

Kristina Davis, Chris Groppi, Hamdi Mani, Caleb Wheeler, Chris Walker

Proceedings Volume 9153, 91533F (2014) https://doi.org/10.1117/12.2056844

KEYWORDS: Receivers, Near field, Optical testing, Phase measurement, Antennas, Calibration, Reliability, Network security, Algorithm development, Diodes

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Proceedings Article | 27 September 2012 Paper

First observations with SuperCam and future plans

Jenna Kloosterman, Tiara Cottam, Brandon Swift, David Lesser, Paul Schickling, Christopher Groppi, Michael Borden, Allison Towner, Per Schmidt, Craig Kulesa, Christian d'Aubigny, Christopher Walker, Dathon Golish, Sander Weinreb, Glenn Jones, Hamdi Mani, Jacob Kooi, Art Lichtenberger, Patrick Puetz, Gopal Narayanan

Proceedings Volume 8452, 845204 (2012) https://doi.org/10.1117/12.925088

KEYWORDS: Clouds, Heterodyning, Integrated optics, Spectroscopy, Waveguides, Electronics, Photography, Signal processing, Relays, Mirrors

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Proceedings Article | 24 September 2012 Paper

The Kilopixel Array Pathfinder Project (KAPPa), a 16 pixel integrated heterodyne focal plane array

Christopher Groppi, Caleb Wheeler, Hamdi Mani, Patrick McGarey, Todd Veach, Sander Weinreb, Damon Russell, Jacob Kooi, Arthur Lichtenberger, Christopher Walker, Craig Kulesa

Proceedings Volume 8452, 84520Y (2012) https://doi.org/10.1117/12.927358

KEYWORDS: Staring arrays, Computer aided design, Heterodyning, Terahertz radiation, Waveguides, Sensors, Connectors, Amplifiers, Receivers, Cryogenics

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Proceedings Article | 15 February 2012 Paper

Intracavity generation of continuous wave terahertz radiation

M. Scheller, A. Young, J. Yarborough, J. Moloney, S. Koch, C. Drouet d'Aubigny, C. Walker

Proceedings Volume 8240, 824007 (2012) https://doi.org/10.1117/12.911943

KEYWORDS: Terahertz radiation, Nonlinear crystals, Crystals, Fabry–Perot interferometers, Mirrors, Heterodyning, Laser resonators, Lithium niobate, Laser crystals, Beam shaping

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Proceedings Article | 28 July 2010 Paper

The Stratospheric THz Observatory (STO)

C. Walker, C. Kulesa, P. Bernasconi, H. Eaton, N. Rolander, C. Groppi, J. Kloosterman, T. Cottam, D. Lesser, C. Martin, A. Stark, D. Neufeld, C. Lisse, D. Hollenbach, J. Kawamura, P. Goldsmith, W. Langer, H. Yorke, J. Sterne, A. Skalare, I. Mehdi, S. Weinreb, J. Kooi, J. Stutzki, U. Graf, M. Brasse, C. Honingh, R. Simon, M. Akyilmaz, P. Puetz, Mark Wolfire

Proceedings Volume 7733, 77330N (2010) https://doi.org/10.1117/12.857765

KEYWORDS: Telescopes, Terahertz radiation, Receivers, Observatories, Spectroscopy, Electronics, Signal processing, Stars, Clouds, Control systems

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Proceedings Article | 15 July 2010 Paper

Large format heterodyne arrays for observing far-infrared lines with SOFIA

C. Walker, C. Kulesa, J. Kloosterman, D. Lesser, T. Cottam, C. Groppi, J. Zmuidzinas, M. Edgar, S. Radford, P. Goldsmith, W. Langer, H. Yorke, J. Kawamura, I. Mehdi, D. Hollenbach, J. Stutzki, H. Huebers, J. R. Gao, C. Martin

Proceedings Volume 7741, 77410Z (2010) https://doi.org/10.1117/12.857811

KEYWORDS: Heterodyning, Terahertz radiation, Receivers, Spectroscopy, Stars, Spectral resolution, Oscillators, Cryogenics, Astronomy, Micromachining

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In the wavelength regime between 60 and 300 microns there are a number of atomic and molecular emission lines that are key diagnostic probes of the interstellar medium. These include transitions of [CII], [NII], [OI], HD, H₂D+, OH, CO, and H₂O, some of which are among the brightest global and local far-infrared lines in the Galaxy. In Giant Molecular Clouds (GMCs), evolved star envelopes, and planetary nebulae, these emission lines can be extended over many arc minutes and possess complicated, often self absorbed, line profiles. High spectral resolution (R> 10⁵) observations of these lines at sub-arcminute angular resolution are crucial to understanding the complicated interplay between the interstellar medium and the stars that form from it. This feedback is central to all theories of galactic evolution. Large format heterodyne array receivers can provide the spectral resolution and spatial coverage to probe these lines over extended regions. The advent of large format (~100 pixel) spectroscopic imaging cameras in the far-infrared (FIR) will fundamentally change the way astronomy is performed in this important wavelength regime. While the possibility of such instruments has been discussed for more than two decades, only recently have advances in mixer and local oscillator technology, device fabrication, micromachining, and digital signal processing made the construction of such instruments tractable. These technologies can be implemented to construct a sensitive, flexible, heterodyne array facility instrument for SOFIA. The instrument concept for StratoSTAR: Stratospheric Submm/THz Array Receiver includes a common user mounting, control system, IF processor, spectrometer, and cryogenic system. The cryogenic system will be designed to accept a frontend insert. The frontend insert and associated local oscillator system/relay optics would be provided by individual user groups and reflect their scientific interests. Rapid technology development in this field makes SOFIA the ideal platform to operate such a modular, continuously evolving instrument.

Proceedings Article | 15 July 2010 Paper

Test and integration results from SuperCam: a 64-pixel array receiver for the 350 GHz atmospheric window

Christopher Groppi, Christopher Walker, Craig Kulesa, Dathon Golish, Jenna Kloosterman, Sander Weinreb, Glenn Jones, Joseph Bardin, Hamdi Mani, Tom Kuiper, Jacob Kooi, Art Lichtenberger, Thomas Cecil, Patrick Puetz, Gopal Narayanan, Abigail Hedden

Proceedings Volume 7741, 77410X (2010) https://doi.org/10.1117/12.857504

KEYWORDS: Spectroscopy, Telescopes, Galactic astronomy, Clouds, Stars, Amplifiers, Waveguides, Receivers, Cryogenics, Mirrors

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Proceedings Article | 15 July 2010 Paper

Terahertz traveling wave tube amplifiers as high-power local oscillators for large heterodyne receiver arrays

Christian Drouet d'Aubigny, Christopher Walker, Abram Young, Paul Gensheimer, Dathon Golish, Christopher Groppi

Proceedings Volume 7741, 774115 (2010) https://doi.org/10.1117/12.857904

KEYWORDS: Electron beams, Terahertz radiation, Waveguides, Optical fibers, Amplifiers, Oscillators, Receivers, Single walled carbon nanotubes, Optical amplifiers, Heterodyning

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Proceedings Article | 19 July 2008 Paper

Future prospects for THz spectroscopy

Christopher Walker, Craig Kulesa, Christopher Groppi, Dathon Golish

Proceedings Volume 7020, 702014 (2008) https://doi.org/10.1117/12.790286

KEYWORDS: Terahertz radiation, Receivers, Telescopes, Space telescopes, Amplifiers, Heterodyning, Stars, Galactic astronomy, Digital signal processing, Observatories

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Proceedings Article | 18 July 2008 Paper

SuperCam: a 64 pixel heterodyne imaging spectrometer

Christopher Groppi, Christopher Walker, Craig Kulesa, Dathon Golish, Jenna Kloosterman, Patrick Pütz, Sander Weinreb, Thomas Kuiper, Jacob Kooi, Glenn Jones, Joseph Bardin, Hamdi Mani, Arthur Lichtenberger, Thomas Cecil, Abigail Hedden, Gopal Narayanan

Proceedings Volume 7020, 702011 (2008) https://doi.org/10.1117/12.790284

KEYWORDS: Spectroscopy, Galactic astronomy, Clouds, Waveguides, Stars, Optical amplifiers, Prototyping, Receivers, Amplifiers, Telescopes

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Proceedings Article | 10 July 2008 Paper

Pre-HEAT: submillimeter site testing and astronomical spectra from Dome A, Antarctica

C. Kulesa, C. Walker, M. Schein, D. Golish, N. Tothill, P. Siegel, S. Weinreb, G. Jones, J. Bardin, K. Jacobs, C. Martin, J. Storey, M. Ashley, J. Lawrence, D. Luong-Van, J. Everett, L. Wang, L. Feng, Z. Zhu, J. Yan, J. Yang, X.-G. Zhang, X. Cui, X. Yuan, J. Hu, Z. Xu, Z. Jiang, H. Yang, Y. Li, B. Sun, W. Qin, Z. Shang

Proceedings Volume 7012, 701249 (2008) https://doi.org/10.1117/12.789741

KEYWORDS: Telescopes, Receivers, Domes, Astronomy, Spectroscopy, Observatories, Heterodyning, Opacity, Space telescopes, Control systems

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Proceedings Article | 10 July 2008 Paper

The PLATO Antarctic site testing observatory

J. Lawrence, G. Allen, M. C. Ashley, C. Bonner, S. Bradley, X. Cui, J. Everett, L. Feng, X. Gong, S. Hengst, J. Hu, Z. Jiang, C. Kulesa, Y. Li, D. Luong-Van, A. Moore, C. Pennypacker, W. Qin, R. Riddle, Z. Shang, J. W. Storey, B. Sun, N. Suntzeff, N. F. Tothill, T. Travouillon, C. Walker, L. Wang, J. Yan, J. Yang, H. Yang, D. York, X. Yuan, X. Zhang, Z. Zhang, X. Zhou, Z. Zhu

Proceedings Volume 7012, 701227 (2008) https://doi.org/10.1117/12.787166

KEYWORDS: Domes, Telescopes, Observatories, Astronomy, Cameras, Temperature metrology, Iridium, Turbulence, Control systems, Solar cells

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Proceedings Article | 6 July 2006 Paper

SuperCam: a 64-pixel heterodyne imaging array for the 870-micron atmospheric window

Christopher Groppi, Christopher Walker, Craig Kulesa, Patrick Pütz, Dathon Golish, Paul Gensheimer, Abigail Hedden, Shane Bussmann, Sander Weinreb, Tom Kuiper, Jacob Kooi, Glenn Jones, Joseph Bardin, Hamdi Mani, Arthur Lichtenberger, Gopal Narayanan

Proceedings Volume 6275, 62750O (2006) https://doi.org/10.1117/12.671856

KEYWORDS: Clouds, Stars, Galactic astronomy, Amplifiers, Carbon monoxide, Spectroscopy, Waveguides, Receivers, Heterodyning, Telescopes

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Proceedings Article | 27 June 2006 Paper

The variable-delay polarization modulator

M. Krejny, D. Chuss, G. Novak, G. Voellmer, E. Wollack, C. Walker, M. Jackson, D. Benford, J. Staguhn, S. Moseley, C. Kulesa, C. Drouet d'Aubigny, D. Golish, R. Loewenstein

Proceedings Volume 6275, 62751N (2006) https://doi.org/10.1117/12.671927

KEYWORDS: Polarization, Modulators, Dielectric polarization, Modulation, Polarimetry, Mirrors, Telescopes, Scattering, Observatories, Optical spheres

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Proceedings Article | 19 May 2006 Paper

Design of a compact low-cost THz imaging scanner

Harvey Schau, Bryan Jennette, Christopher Walker, Christian d'Aubigny

Proceedings Volume 6212, 62120R (2006) https://doi.org/10.1117/12.665138

KEYWORDS: Terahertz radiation, Imaging systems, Scanners, Infrared radiation, Sensors, Optical design, Prototyping, Helium, Bolometers, Infrared imaging

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Proceedings Article | 20 October 2004 Paper

The Antarctic planet interferometer

Mark Swain, Christopher Walker, Wesley Traub, John Storey, Vincent Coude du Foresto, Eric Fossat, Farrokh Vakili, Anthony Stark, James Lloyd, Peter Lawson, Adam Burrows, Michael Ireland, Rafael Millan-Gabet, Gerard van Belle, Benjamin Lane, Gautam Vasisht, Tony Travouillon

Proceedings Volume 5491, (2004) https://doi.org/10.1117/12.552221

KEYWORDS: Interferometers, Planets, Exoplanets, Infrared radiation, Stars, Interferometry, Telescopes, Surface conduction electron emitter displays, Domes, Infrared detectors

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Proceedings Article | 20 October 2004 Paper

The potential of conductive waveguides for nulling interferometry

Udo Wehmeier, Mark Swain, Christian Drouet d'Aubigny, Dathon Golish, Christopher Walker

Proceedings Volume 5491, (2004) https://doi.org/10.1117/12.549954

KEYWORDS: Waveguides, Nulling interferometry, Mid-IR, Integrated optics, Computer aided design, Information operations, Interferometers, Phase shifts, Instrument modeling, Signal attenuation

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Proceedings Article | 20 October 2004 Paper

Mid-infrared spatial filter fabrication using laser chemical etching

Christian Drouet d'Aubigny, Christopher Walker, Dathon Golish

Proceedings Volume 5491, (2004) https://doi.org/10.1117/12.552671

KEYWORDS: Waveguides, Spatial filters, Silicon, Chemical lasers, Mid-IR, Signal attenuation, Etching, Micromachining, Terahertz radiation, Wave propagation

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Proceedings Article | 8 October 2004 Paper

High sensitivity 810 GHz SIS receivers at AST/RO

Patrick Putz, Stefan Glenz, Rafael Teipen, Thomas Tils, Netty Honingh, Karl Jacobs, Abigail Hedden, Craig Kulesa, Christopher Groppi, Christopher Walker

Proceedings Volume 5498, (2004) https://doi.org/10.1117/12.550894

KEYWORDS: Receivers, Heterodyning, Waveguides, Niobium, Temperature metrology, Astronomy, Electrodes, Chemical mechanical planarization, Observatories, Carbon

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Proceedings Article | 8 October 2004 Paper

First results from DesertSTAR: a 7-pixel 345-GHz heterodyne array receiver for the Heinrich Hertz Telescope

Christopher Groppi, Christopher Walker, Craig Kulesa, Dathon Golish, Abigail Hedden, Gopal Narayanan, Arthur Lichtenberger, Jacob Kooi, Urs Graf, Stefan Heyminck

Proceedings Volume 5498, (2004) https://doi.org/10.1117/12.552492

KEYWORDS: Receivers, Telescopes, Computing systems, Heterodyning, Waveguides, Cryogenics, Control systems, Computer aided design, Mirrors, Optical amplifiers

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Proceedings Article | 30 September 2004 Paper

A 350-µm array polarimeter using translational modulators

David Chuss, Dominic Benford, Chris Walker, S. Harvey Moseley, Giles Novak, Johannes Staguhn, Edward Wollack

Proceedings Volume 5492, (2004) https://doi.org/10.1117/12.551382

KEYWORDS: Polarization, Polarimetry, Modulators, Space telescopes, Telescopes, Sensors, Magnetism, Interferometers, Modulation, Stars

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Proceedings Article | 28 September 2004 Paper

Forecast for HEAT on Dome A, Antarctica: the High Elevation Antarctic Terahertz Telescope

Christopher Walker, Craig Kulesa, Dathon Golish, Abigail Hedden, K. Jacobs, Juergen Stutzki, J. Gao, Jacob Kooi, Dave Glaister, Willy Gully, Imran Mehdi, Mark Swain, Peter Siegel

Proceedings Volume 5489, (2004) https://doi.org/10.1117/12.551424

KEYWORDS: Telescopes, Terahertz radiation, Space telescopes, Receivers, Stars, Cryogenics, Cryocoolers, Galactic astronomy, Clouds, Heterodyning

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Proceedings Article | 19 November 2003 Paper

Extrasolar planet science with the Antarctic planet interferometer

James Lloyd, Benjamin Lane, Mark Swain, John Storey, Tony Travouillon, Wesley Traub, Christopher Walker

Proceedings Volume 5170, (2003) https://doi.org/10.1117/12.506895

KEYWORDS: Exoplanets, Earth's atmosphere, Turbulence, Planets, Interferometers, Interferometry, Atmospheric sciences, Astronomy, Humidity

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Proceedings Article | 26 February 2003 Paper

Far-infrared interferometer technology development: a progress report

Mark Swain, Philip Dumont, Peter Lawson, James Moore, Robert Smythe, Christopher Walker, Christian Drouet d'Aubigny

Proceedings Volume 4852, (2003) https://doi.org/10.1117/12.460733

KEYWORDS: Cryogenics, Interferometers, Ferroelectric materials, Integrated optics, Liquids, Spatial filters, Interferometry, Nitrogen, Eye, Servomechanisms

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Proceedings Article | 26 February 2003 Paper

Laser micromachining of waveguide devices for sub-mm and far-IR interferometry and detector arrays

Christian Drouet d'Aubigny, Christopher Walker, Dathon Golish, Mark Swain, Philip Dumont, Peter Lawson

Proceedings Volume 4852, (2003) https://doi.org/10.1117/12.460865

KEYWORDS: Waveguides, Micromachining, Interferometry, Silicon, Beam splitters, Terahertz radiation, Semiconductor lasers, Chlorine, Computer aided design, Laser interferometry

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Proceedings Article | 17 February 2003 Paper

Desert STAR: a 7-pixel 345-GHz heterodyne array receiver for the Heinrich Hertz Telescope

Christopher Groppi, Christopher Walker, Craig Kulesa, Dathon Golish, Abigail Hedden, P. Gensheimer, Gopal Narayanan, Arthur Lichtenberger, Urs Graf, Stefan Heyminck

Proceedings Volume 4855, (2003) https://doi.org/10.1117/12.459361

KEYWORDS: Receivers, Telescopes, Computer aided design, Heterodyning, Waveguides, Computing systems, Temperature metrology, Stars, Mirrors, Electronics

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Proceedings Article | 17 February 2003 Paper

TREND: a low-noise terahertz receiver user instrument for AST/RO at the South Pole

Eyal Gerecht, Sigfrid Yngvesson, John Nicholson, Yan Zhuang, Fernando Rodriguez-Morales, Xin Zhao, Dazhen Gu, Richard Zannoni, Michael Coulombe, Jason Dickinson, Thomas Goyette, Jerry Waldman, Christopher Groppi, Abigail Hedden, Dathon Golish, Christopher Walker, Antony Stark, Christopher Martin, Adair Lane

Proceedings Volume 4855, (2003) https://doi.org/10.1117/12.459316

KEYWORDS: Receivers, Terahertz radiation, Telescopes, Antennas, Silicon, Gas lasers, Astronomy, Space telescopes, Carbon monoxide, Optical instrument design

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Proceedings Article | 17 February 2003 Paper

Integrated heterodyne array receivers for submillimeter astronomy

Christopher Walker, Christopher Groppi, Christian Drouet d'Aubigny, Craig Kulesa, Abigail Hedden, Daniel Prober, Irfan Siddiqi, Jacob Kooi, Gordon Chen, Arthur Lichtenberger

Proceedings Volume 4855, (2003) https://doi.org/10.1117/12.459375

KEYWORDS: Terahertz radiation, Receivers, Waveguides, Heterodyning, Astronomy, Amplifiers, Staring arrays, Cameras, Bolometers, Spectral resolution

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Proceedings Article | 28 September 2001 Paper

Laser microchemical etching of waveguides and quasi-optical components

Christian Drouet d'Aubigny, Christopher Walker, Bryan Jones

Proceedings Volume 4557, (2001) https://doi.org/10.1117/12.442932

KEYWORDS: Silicon, Waveguides, Terahertz radiation, Etching, Lenses, Semiconductor lasers, Micromachining, Chlorine, Dielectrics, Laser systems engineering

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Proceedings Article | 3 July 2000 Paper

Submillimeter-wave receiver system for the Large Binocular Telescope

Christian Drouet d'Aubigny, Christopher Walker, Christopher Groppi, John Hill, John Bieging, Stephen Pompea

Proceedings Volume 4015, (2000) https://doi.org/10.1117/12.390421

KEYWORDS: Mirrors, Telescopes, Receivers, Waveguides, Off axis mirrors, Point spread functions, Heterodyning, Optical instrument design, Observatories, Atmospheric optics

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Proceedings Article | 3 July 2000 Paper

345-GHz array receiver for the Heinrich Hertz Telescope

Christopher Groppi, Christopher Walker, Aimee Hungerford, Gopal Narayanan, Arthur Lichtenberger

Proceedings Volume 4015, (2000) https://doi.org/10.1117/12.390418

KEYWORDS: Receivers, Telescopes, Computing systems, Computer aided design, Rockets, Waveguides, Electronics, Heterodyning, Optical isolators, Optical amplifiers

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Proceedings Article | 3 July 2000 Paper

Laser micromachining of terahertz systems

Christian Drouet d'Aubigny, Christopher Walker, Bryan Jones

Proceedings Volume 4015, (2000) https://doi.org/10.1117/12.390455

KEYWORDS: Micromachining, Etching, Silicon, Terahertz radiation, Waveguides, Observatories, Semiconductor lasers, Semiconducting wafers, Computer aided design, Tolerancing

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Proceedings Article | 20 June 2000 Paper

Far-infrared array reciever (FAR) for SOFIA

Christopher Walker, Christopher Groppi, Christian Drouet d'Aubigny, Gondon Chen, Rudolf Schieder, Gopal Narayanan, Arthur Lichtenberger, Peter Siegel

Proceedings Volume 4014, (2000) https://doi.org/10.1117/12.389093

KEYWORDS: Waveguides, Terahertz radiation, Receivers, Bolometers, Staring arrays, Silicon, Far infrared lasers, Diodes, Telescopes, Laser systems engineering

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Proceedings Article | 31 July 1998 Paper

Plans for a 10-m submillimeter-wave telescope at the South Pole

Antony Stark, John Carlstrom, Frank Israel, Karl Menten, Jeffrey Peterson, Thomas Phillips, Giorgio Sironi, Christopher Walker

Proceedings Volume 3357, (1998) https://doi.org/10.1117/12.317383

KEYWORDS: Telescopes, Mirrors, Laminated object manufacturing, Monochromatic aberrations, Surface plasmons, Observatories, Antennas, Stars, Diffraction, Galactic astronomy

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Proceedings Article | 31 July 1998 Paper

Laser micromachining of silicon: a new technique for fabricating terahertz imaging arrays

Christopher Walker, Aimee Hungerford, Gopal Narayanan, Christopher Groppi, Theodore Bloomstein, Stephen Palmacci, Margaret Stern, Jane Curtin

Proceedings Volume 3357, (1998) https://doi.org/10.1117/12.317377

KEYWORDS: Waveguides, Silicon, Terahertz radiation, Etching, Computer aided design, Micromachining, Fabrication, Semiconductor lasers, Bolometers, Imaging arrays

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Showing 5 of 68 publications

Conference Committee Involvement (7)

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X

14 December 2020 | Online Only, California, United States

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX

12 June 2018 | Austin, Texas, United States

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII Posters

28 June 2016 | Edinburgh, United Kingdom

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII

28 June 2016 | Edinburgh, United Kingdom

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII

24 June 2014 | Montréal, Quebec, Canada

Showing 5 of 7 Conference Committees

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