Imaging Beyond the Visible in the Short Wave Infrared with Indium Gallium Arsenide Martin H. Ettenberg, Ph. D., Director of Imaging Products 3490 US Rt. 1, Bldg. 12 Princeton, NJ 08540 Ph: 609-520-0610 Fax: 609-520-0638 [email protected]www.sensorsinc.com
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Imaging Beyond the Visible in the Short Wave Infrared with Indium Gallium Arsenide
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Imaging Beyond the Visible in the Short Wave Infrared withIndium Gallium Arsenide
Martin H. Ettenberg, Ph. D., Director of Imaging Products
•What is the Short Wave Infrared?•How the Devices Are
Manufactured•Applications the Technology
Serves•R&D Topics
Imaging Beyond VisibleTM
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What is the Short Wave Infrared?
Imaging Beyond VisibleTM
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One-Dimensional InGaAs FPA
ROIC InGaAs PDA
Current Standard Sizes Available:1024 elements on 25 m pitch512 and 256 elements on 25 m and 50 m pitch1.7 m and 2.2 m cutoff commercially available2.6 m has been demonstrated at room temperature
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2D Array Formats1.7 m cutoff commercially available
• 128x128x60 m (First array >12 years old)• 320x240x40 m (Old Industry standard)• 320x256x25 m (Industry standard)• 640x512x25 m (Industry standard)• Custom Sizes available through foundry services–1024x1024x17 m photodiode array- demonstrated
algorithms enable the user to identify the nature of objects in a scene in a sense through “coarse” hyperspectral imaging.
• Multisensor fusion enables imagers that are inherently more resistant to countermeasures.
SWIR
Visible
Thermal
Courtesy Dean Scribner, NRL
Commercial Applications
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Commercial Applications
Commercial applications break into two major catagories, imaging and spectroscopy.
Imaging- Observing a scene to fabricate and imageOnline Processing- Detecting moistureThermal analysis- Metal Smelting, Furnace monitoringInspection of Phenomenology-Agriculture, Pharmaceutical,
SemiconductorsSpectral- Looking at multiple wavelengths to conduct an analysis
From “High Resolution Fiber Grating Optical Network Monitor,” Koeppen,Wagener, Strasser, and DeMarco, Proceedings of NFOEC, Orlando (1998)
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Optical Performance MonitorsAre Needed All Over The Network
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Industrial Process Monitors
•Plastic Sorting•Agricultural Sorting•Fruit and Vegetable
imperfections•Seed sorting
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Thermal Imaging
•Lattice matched InGaAs is useful for imaging thermal processes above 80ºC–Too cold for silicon–Glass is transparent
•Glass manufacturing•Smelting of metals•Furnace monitoring
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Inspection Applications• Many features can be seen in
the SWIR that are not apparent in the visible– Si is transparent to light
>1.1 m•Allows defects in Si to
be detected before processing•In process defects can
be identified•Emission microscopy
used in failure analysis– Some plastics are
transparent to SWIR light and not visible light making measurement of fill levels difficult
Imaging Beyond VisibleTM
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Renoir’s Luncheon of the Boating Party; courtesy of the Phillips Collection, Washington, DC
Imaging Through Paint(Art Restoration)
R&D
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What needs Development?
•Longer wavelength cameras operating at room temperature–Long wavelength materials because of the defects
have very high dark current•New read out integrated circuits
–Handle large amounts of dark current–Large gain for high sensitivity applications–Advanced features
•High speed readouts•Wide Bandwidth detectors (communication and imaging)
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Who Do We Work With?
•Princeton University•University of Virginia•Penn State•Rutgers UniversitySBIR/STTR and NIST Programs allow for
collaboration on long term research
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Conclusions
•InGaAs imaging technology has seen major advances in the last 10 years–Imaging arrays capable of imaging at night–Avalanche Photodiode Arrays (APDs)
•InGaAs has many more opportunities for research to improve the technology–Longer wavelength materials–Lowering the dark current in all InGaAs alloys–Improving the ROIC circuits
•Imaging technologies will become critical in commercial and military applications