Photonics/Optics

Rugged, Tunable Extended-Cavity Diode Laser

This laser is relatively insensitive to vibration.

A rugged, tunable extended-cavity diode laser (ECDL) has been developed to satisfy stringent requirements for frequency stability, notably including low sensitivity to vibration. This laser is designed specifically for use in an atomic-clock experiment to be performed aboard the International Space Station (ISS). Lasers of similar design would be suitable for use in terrestrial laboratories engaged in atomic-clock and atomic-physics research.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Calibration, Lasers, Lasers, Vibration, Vibration, Durability, Durability, Spacecraft
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Thulium Puts Power Behind Eyesafe Fiber Lasers

One of the key advantages of fiber laser technology stems from the high conversion efficiency of the multimode pump radiation into high-brightness, single-mode laser light within the doped fiber lasing medium. Ytterbium-doped fiber lasers operating around 1μm often achieve around 80% pump- to-laser conversion efficiency and corresponding wall plug efficiencies over 25%, depending on the pump diodes used in the laser. As a result, high-power CW fiber lasers are more compact and require less cooling than a traditional solid-state laser of similar power.

Posted in: Articles, Features, ptb catchall, Photonics, Downsizing, Fiber optics, Lasers, Fiber optics, Lasers, Pumps, Radiation
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Reactive Solders Improve Fiber Couplers and OE Bonding

Optical and optoelectronic (OE) devices are being rapidly integrated into many facets of everyday life. From telecommunications to sensor applications, these devices are expected to perform accurately and reliably for long periods of time.

Posted in: Application Briefs, Applications, ptb catchall, Photonics, Optics, Sensors and actuators, Telecommunications, Optics, Sensors and actuators, Telecommunications, Joining
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Recirculation of Laser Power in an Atomic Fountain

Optical and electronic subsystems of a frequency standard can be simplified.

A new technique for laser-cooling atoms in a cesium atomic fountain frequency standard relies on recirculation of laser light through the atom-collection region of the fountain. The recirculation, accomplished by means of reflections from multiple fixed beam-splitter cubes, is such that each of two laser beams makes three passes. As described below, this recirculation scheme offers several advantages over prior designs, including simplification of the laser system, greater optical power throughput, fewer optical and electrical connections, and simplification of beam power balancing.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Lasers, Lasers, Cooling
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Simplified Generation of High-Angular-Momentum Light Beams

Inherent properties of a WGM resonator and optical fiber are exploited.

A simplified method of generating a beam of light having a relatively high value of angular momentum (see figure) involves the use of a compact apparatus consisting mainly of a laser, a whispering-gallery-mode (WGM) resonator, and optical fibers. The method also can be used to generate a Bessel beam. (“Bessel beam” denotes a member of a class of non-diffracting beams, so named because their amplitudes are proportional to Bessel functions of the radii from their central axes. High-order Bessel beams can have high values of angular momentum.)

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Fiber optics, Lasers, Fiber optics, Lasers, Performance upgrades, Acoustics, Acoustics
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Complex Type-II Interband Cascade MQW Photodetectors

Multiple active subregions, each optimized for a different color, would enable multicolor operation.

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: Briefs, ptb catchall, Tech Briefs, Photonics, Architecture, Optics, Sensors and actuators, Architecture, Optics, Sensors and actuators, Product development
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Interferometric Quantum-Nondemolition Single-Photon Detectors

These detectors would function independently of frequency.

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.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Measurements, Lasers, Lasers
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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.

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.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics, Calibration, Lasers, Spectroscopy, Lasers, Spectroscopy
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Clearer Images on Near Infrared Camera Made Possible with Filters

The James Webb Space Telescope (JWST) is scheduled for launch in 2013 and aims to unravel the history of earlier galaxies, linking the Big Bang to the Milky Way Galaxy. JWST’s Near InfraRed Camera (NIRCam) is a filter-based instrument covering the spectral range of 0.6 to 5.0 microns. The Principle Investigator for NIRCam is Dr. Marcia Reike of the University of Arizona, while the Advanced Technology Center (ATC) of Lockheed Martin is responsible for its manufacture, integration, and testing. Barr Associates recently was selected to design, manufacture, and test 30 filters for the JWST NIRCam. Barr previously provided spaceflight filters for Lockheed Martin ATC, including those for the Solar-B and shuttle glow experiments.

Posted in: Application Briefs, Optical Components, Optics, Design processes, Optics, Optics, Performance upgrades, Research and development, Suppliers
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Deformable Mirror to Help NASA Search for New Planets

Boston Micromachines, a provider of MEMS-based deformable mirror products for adaptive optics systems, is developing a deformable mirror that will aid NASA in the search for extra-solar planets. The mirror comprises a micromirror array consisting of 331 closely packed ultra-flat hexagonal mirror elements. Each element is capable of tip, tilt, and piston motion with nanometer precision as required for a space-based, hyper-contrast coronagraph imaging telescope.

Posted in: Application Briefs, Optical Components, Optics, Mirrors, Optics, Optics
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