Photonics

Mosaic-Detector-Based Fluorescence Spectral Imager

This portable instrument would perform comparably to larger laboratory instruments. NASA’s Jet Propulsion Laboratory, Pasadena, California A battery-powered, pen-sized, portable instrument for measuring molecular fluorescence spectra of chemical and biological samples in the field has been proposed. Molecular fluorescence spectroscopy is among the techniques used most frequently in laboratories to analyze compositions of chemical and biological samples. Heretofore, it has been possible to measure fluorescence spectra of molecular species at relative concentrations as low as parts per billion (ppb), with a few nm spectral resolution. The proposed instrument would include a planar array (mosaic) of detectors, onto which a fluorescence spectrum would be spatially mapped. Unlike in the larger laboratory-type molecular fluorescence spectrometers, mapping of wavelengths to spatial positions would be accomplished without use of relatively bulky optical parts. The proposed instrument is expected to be sensitive enough to enable measurement of spectra of chemical species at relative concentrations

Posted in: Photonics, Imaging, Briefs

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Design and Fabrication of High-Efficiency CMOS/CCD Imagers

Economical production of back-illuminated CMOS/CCD imagers should soon become possible. NASA’s Jet Propulsion Laboratory, Pasadena, California An architecture for back-illuminated complementary metal oxide/semiconductor (CMOS) and charge-coupled-device (CCD) ultraviolet/visible/near infrared-light image sensors, and a method of fabrication to implement the architecture, are undergoing development. The architecture and method are expected to enable realization of the full potential of back-illuminated CMOS/CCD imagers to perform with high efficiency, high sensitivity, excellent angular response, and in-pixel signal processing. The architecture and method are compatible with next-generation CMOS dielectric-forming and metallization techniques, and the process flow of the method is compatible with process flows typical of the manufacture of very-large-scale integrated (VLSI) circuits.

Posted in: Photonics, Imaging, Briefs

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Improved Underwater Excitation-Emission Matrix Fluorometer

This is a higher-resolution, smaller, more-capable successor to a prior instrument. Stennis Space Center, Mississippi A compact, high-resolution, two-dimensional excitation-emission matrix fluorometer (EEMF) has been designed and built specifically for use in identifying and measuring the concentrations of organic compounds, including polluting hydrocarbons, in natural underwater settings. Heretofore, most EEMFs have been designed and built for installation in laboratories, where they are used to analyze the contents of samples collected in the field and brought to the laboratories. Because the present EEMF can be operated in the field, it is better suited to measurement of spatially and temporally varying concentrations of substances of interest.

Posted in: Photonics, Imaging, Briefs

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Metrology Camera System Using Two-Color Interferometry

3D locations of multiple targets are determined without mechanical scanning. NASA’s Jet Propulsion Laboratory, Pasadena, California A metrology system that contains no moving parts simultaneously measures the bearings and ranges of multiple reflective targets in its vicinity, enabling determination of the three-dimensional (3D) positions of the targets with submillimeter accuracy. The system combines a direction-measuring metrology camera and an interferometric range-finding subsystem. Because the system is based partly on a prior instrument denoted the Modulation Sideband Technology for Absolute Ranging (MSTAR) sensor and because of its 3D capability, the system is denoted the MSTAR3D. Developed for use in measuring the shape (for the purpose of compensating for distortion) of large structures like radar antennas, it can also be used to measure positions of multiple targets in the course of conventional terrestrial surveying.

Posted in: Photonics, Imaging, Briefs

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Image Sensors Decades Old But Not Yet Mature

There’s no rule that says when a technology becomes mature, but one might think that image sensors would be by now, 40 years after their conception. Nothing could be further from the truth. After decades of use in fax machines, scanners, and camcorders, image sensors are now in the largest growth period in their history, and much of the innovation is still happening.

Posted in: Features, ptb catchall, Photonics, Articles

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DisplayPort Technology — Heir Apparent to VGA?

For the last 20 years we have connected our monitors to our computer systems having the confidence that upon turn-on, we could surf or create with never a consideration of whether the display would operate satisfactorily. VGA (Video Graphics Adaptor) technology enabled us to do that with CRTs as well as with flat panel displays. Now, however, the viewing benchmarks are being reset, as are system design considerations. There’s a new interface on the horizon called DisplayPort!

Posted in: ptb catchall, Applications, Photonics, Application Briefs

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Optoelectronic System Measures Distances to Multiple Targets

This system operates at an update rate >10 Hz. NASA’s Jet Propulsion Laboratory, Pasadena, California An optoelectronic metrology apparatus now at the laboratory-prototype stage of development is intended to repeatedly determine distances of as much as several hundred meters, at submillimeter accuracy, to multiple targets in rapid succession. The underlying concept of optoelectronic apparatuses that can measure distances to targets is not new; such apparatuses are commonly used in general surveying and machining. However, until now such apparatuses have been, variously, constrained to (1) a single target or (2) multiple targets with a low update rate and a requirement for some a priori knowledge of target geometry. When fully developed, the present apparatus would enable measurement of distances to more than 50 targets at an update rate >10 Hz, without a requirement for a priori knowledge of target geometry.

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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