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Bandara, S. V.

Publications and source records attributed to Bandara, S. V..

72 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

Quantum Well Infrared Photodetectors (QWIPs) for Astronomy

In recent years, many research groups in the world have demonstrated large format Quantum Well Infrared Photodetector (QWIP) focal plane arrays for various thermal imaging applications. QWIPs as opposed to conventional low bandgap infrared detectors, are limited by thermionic dark current and not tunneling currents down to 30K or less. As a result the performance of QWIPs can be substantially improved (orders of magnitude) by cooling from 70K to 30K. Cooling does not induce any nonuniformity or 1/f noise in QWIP focal plane arrays. In this paper, we discuss the development of highly uniform long- wavelength QWIPs for astronomical applications.

Gunapala, S. D.↗
NASA NTRS1997

Portable Long-Wavelength Infrared Camera for Civilian Application

In this paper, we discuss the performance of this portable long-wavelength infrared camera in quantum efficiency, NEAT, minimum resolvable temperature differnce (MRTD), uniformity, etc. and its application in science, medicine and defense.

infrared wavelength portable↗
NASA NTRS1997

(abstract) 9 (micro)m Cutoff 640x480 Quantum Well Infrared Photodetector (QWIP) Focal Plane Array Camera

Long wavelength infrared (LWIR) detectors, 8 (micro)m to 12 (micro)m, are of great interest for a variety of ground-based and space-borne applications. These applications have placed stringent requirements on the performance of the infrared detectors and arrays including high detectivity, low dark current, uniformity, radiation hardness, and low power dissipation. I will discuss the development and progress of GaAs based long-wavelength quantum well infrared photodetectors (QWIPs) to meet those stringent requirements and the demonstration of a 9 (micro)m cutoff 640x480 QUIP focal plane array camera. The noise equivalent temperature difference of the focal plane array is 25 mK at 300 K background and the operating temperature is 70 K.

long wavelength infrared detectors LWIR detector a↗
NASA NTRS1997

(abstract) Applications of Long-wavelength 256x256 GaAs/Al&subx;Ga&sub1-x;As Quantum Well Infrared Photodetector Hand-held Camera

A 9 (micro)m 256x256 hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE(gamma)) of 26 mK has been achieved. In this presentation, we discuss the development of this very sensitive long wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array, its performance in quantum efficience, NA(gamma), minimum resolvable temperature (MRTD), uniformity, operability, and its applications.

GaAs infrared photodetector quantum well QUIP nois↗
NASA NTRS1997

Long-Wavelength 640 x 484 GaAs/Al(x)Ga(1-x)As Quantum Well Infrared Photodetector Focal Plane Array Camera

A 9 micrometers cutoff 640 x 484 hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE.deltaT) of 43 mK has been achieved. In this paper, we discuss the development of this very sensitive long wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array (FPA) and its performance in quantum efficiency, NE.deltaT, uniformity, and operability.

Gunapala, S. D.↗
NASA NTRS1996

Long-wavelength 256x256 QWIP Hand-held Camera

In this paper, we discuss the development of very sensitive long wavelength infrared (LWIR) GaAs/AlxGa1-xAs quantum well infrared photodetectors (QWIPs), fabrication of random reflectors for efficient light coupling, and the demonstration of first hand-held long-wavelength 256x256 QWIP focal plane array camera. Excellent imagery, with a noise equivalent differential temperature of 25 mK has been achieved.

long↗
NASA NTRS1996

Long Wavelength Quantum Well Infrared Photodetector (QWIP) Research at Jet Propulsion Laboratory

One of the simplest device realizations of the classic particle-in-the-box problem of basic quantum mechanics is the Quantum Well Infrared Photodetector (QWIP). Optimization of the detector design and material growth and processing has culminated in the realization of a 15 ??utoff 128x128 focal plane array camera and a camera with large (256x256 pixel) focal plane array of QWIPs which can see at 8.5 ??holding forth great promise for a variety of applications in the 6-25 ??avelength range. This paper discusses the physics of the QWIP and QWIP technology development at Jet Propulsion Laboratory

QWIP↗
NASA NTRS1996

Long-Wavelength 256 x 256 QWIP Hand-Held Camera

In this paper, we discuss the development of very sensitive long wavelength infrared (LWIR) GaAs/Al(x)Ga(l-x)As quantum well infrared photodetectors (QWIPs), fabrication of random reflectors for efficient light coupling, and the demonstration of the first hand-held long-wavelength 256 x 256 QWIP focal plane array camera. Excellent imagery, with a noise equivalent differential temperature (NE Delta T) of 25 mK has been achieved.

Gunapala, S. D.↗
NASA NTRS1996

GaAs Infrared Detectors

It is customary to make infrared (IR) detectors in the long wavelength range (8-20 (micro)m) by utilizing the interband transition which promotes an electron across the band gap (E(sub g)) from the valence band to the conduction. These photo-electrons can be collected efficiently, thereby producing a photocurrent in the external circuit.

infrared detectors infrared photodetector↗