Photonics

Complex Type-II Interband Cascade MQW Photodetectors

Multiple active subregions, each optimized for a different color, would enable multicolor operation. NASA’s Jet Propulsion Laboratory, Pasadena, California Multiple-quantum-well (MQW) photodetectors of a proposed type would contain active regions comprising multiple superlattice subregions. These devices would have complex structures: The superlattice of each subregion would be designed for enhanced absorption of photons in a desired wavelength band (typically in the infrared) and multiple subregions of different design would be cascaded for multicolor operation.

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

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Interferometric Quantum-Nondemolition Single-Photon Detectors

These detectors would function independently of frequency. NASA’s Jet Propulsion Laboratory, Pasadena, California Two interferometric quantum-nondemolition (QND) devices have been proposed: (1) a polarization-independent device and (2) a polarization-preserving device. The prolarization-independent device works on an input state of up to two photons, whereas the polarization-preserving device works on a superposition of vacuum and single-photon states. The overall function of the device would be to probabilistically generate a unique detector output only when its input electromagnetic mode was populated by a single photon, in which case its output mode would also be populated by a single photon.

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Ring-Down Spectroscopy for Characterizing a CW Raman Laser

Parameters of operation can be obtained from a single ring-down scan. NASA’s Jet Propulsion Laboratory, Pasadena, California A relatively simple technique for characterizing an all-resonant intracavity continuous- wave (CW) solid-state Raman laser involves the use of ring-down spectroscopy. As used here, “characterizing” signifies determining such parameters as threshold pump power, Raman gain, conversion efficiency, and quality factors (Q values) of the pump and Stokes cavity modes.

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Digital Servos, Software Chart New Directions in Optical Scanning

Optical scanners, or servo-controlled, limited-rotation motors with laser-beam steering mirrors, were first introduced 40 years ago by General Scanning. Since then, they have become the enabling technology behind many innovative products across many different industries, including medical imaging, industrial machining, product identification, biomedical research, automotive manufacturing, and many more.

Posted in: Features, ptb catchall, Photonics, Articles

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Design Software Bridges Optical/Mechanical Gap for Life Sciences

The inherently interdisciplinary nature of developing instrumentation for life sciences requires a high level of collaboration between scientists and engineers across the fields of analytical or clinical chemistry, optics, mechanics, material science, and microbiology. Moreover, product development teams are competing for first-tomarket benefits that are driven by intellectual property lifetimes and insuring an installed base quickly to realize recurring consumable sales. Concurrently, product designers need to comply with current Good Manufacturing Practices (cGMP). System-level modeling enables adherence to the methodical design process without the cost and time associated with iterative hardware prototyping and laboratory and clinical testing.

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

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Instrumented Spindle Improves Manufacturing of Optical Materials

Sensors and data acquisition system provide real-time visibility of grinding system operation. Lion Precision and Professional Instruments, St. Paul, Minnesota High-performance materials such as ceramics, optics, and alloy steels are manufactured using abrasive grinding technology. Until now, the grinding wheel and process conditions have been difficult to measure in production.

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Flexible Laser Design Targets Low-Volume Material Processing Needs

A flexible approach to diode-pumped laser design combines customized performance with cost-effective manufacturing. Coherent, Inc., Santa Clara, California Q-switched, diode-pumped solid-state lasers with an end-pumped cavity design are now widely used in micromachining, materials processing, marking, and related applications. They are used to process a broad range of materials including metals, glass, plastics, and semiconductors. But this application diversity creates a concomitant need for laser diversity. Namely, while each application requires superior reliability and performance, the definition of “superior performance” is very application-specific. For example, some metal ablation applications may benefit from a long laser pulse, whereas semiconductor scribing needs a short pulse and a very high pulse repetition rate.

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