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Numerical optimization of integrating cavities for diffraction-limited millimeter-wave bolometer arrays

Glenn, Jason and Chattopadhyay, Goutam and Edgington, Samantha F. and Lange, Andrew E. and Bock, James J. and Mauskopf, Philip D. and Lee, Adrian T. (2002) Numerical optimization of integrating cavities for diffraction-limited millimeter-wave bolometer arrays. Applied Optics, 41 (1). pp. 136-142. ISSN 0003-6935. doi:10.1364/AO.41.000136.

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Far-infrared to millimeter-wave bolometers designed to make astronomical observations are typically encased in integrating cavities at the termination of feedhorns or Winston cones. This photometer combination maximizes absorption of radiation, enables the absorber area to be minimized, and controls the directivity of absorption, thereby reducing susceptibility to stray light. In the next decade, arrays of hundreds of silicon nitride micromesh bolometers with planar architectures will be used in ground-based, suborbital, and orbital platforms for astronomy. The optimization of integrating cavity designs is required for achieving the highest possible sensitivity for these arrays. We report numerical simulations of the electromagnetic fields in integrating cavities with an infinite plane-parallel geometry formed by a solid reflecting backshort and the back surface of a feedhorn array block. Performance of this architecture for the bolometer array camera (Bolocam) for cosmology at a frequency of 214 GHz is investigated. We explore the sensitivity of absorption efficiency to absorber impedance and backshort location and the magnitude of leakage from cavities. The simulations are compared with experimental data from a room-temperature scale model and with the performance of Bolocam at a temperature of 300 mK. The main results of the simulations for Bolocam-type cavities are that (1) monochromatic absorptions as high as 95% are achievable with <1% cross talk between neighboring cavities, (2) the optimum absorber impedances are 400 Ω/sq, but with a broad maximum from ~150 to ~700 Ω/sq, and (3) maximum absorption is achieved with absorber diameters ≥1.5λ. Good general agreement between the simulations and the experiments was found.

Item Type:Article
Related URLs:
URLURL TypeDescription
Glenn, Jason0000-0001-7527-2017
Chattopadhyay, Goutam0000-0001-7942-5025
Bock, James J.0000-0002-5710-5212
Mauskopf, Philip D.0000-0001-6397-5516
Additional Information:© 2002 Optical Society of America. Received 9 February 2001; revised manuscript received 7 August 2001. We thank Jonas Zmuidzinas for helpful discussions and Sunil Golwala for critical comments on the manuscript. J. Glenn and A. E. Lange acknowledge support from National Science Foundation (NSF) grant AST-9618798. A. Lee was supported by NSF grant AST-9120005.
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Issue or Number:1
Classification Code:OCIS codes: 040.1240, 040.3060, 030.1940
Record Number:CaltechAUTHORS:20111102-141515126
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Official Citation:Jason Glenn, Goutam Chattopadhyay, Samantha F. Edgington, Andrew E. Lange, James J. Bock, Philip D. Mauskopf, and Adrian T. Lee, "Numerical Optimization of Integrating Cavities for Diffraction-Limited Millimeter-Wave Bolometer Arrays," Appl. Opt. 41, 136-142 (2002)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:27593
Deposited By: Ruth Sustaita
Deposited On:03 Nov 2011 02:20
Last Modified:09 Nov 2021 16:50

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