Digital Beam Deflectors Based Partly on Liquid Crystals

Laser beams are switched to different directions, without using solid moving parts.

A digital beam deflector based partly on liquid crystals has been demonstrated as a prototype of a class of optical beam-steering devices that contain no mechanical actuators or solid moving parts. Such beam-steering devices could be useful in a variety of applications, including free-space optical communications, switching in fiber-optic communications, general optical switching, and optical scanning. Liquid crystals are of special interest as active materials in nonmechanical beam steerers and deflectors because of their structural flexibility, low operating voltages, and the relatively low costs of fabrication of devices that contain them. Recent advances in synthesis of liquid-crystal materials and design of the nematic-liquid-crystal cells have resulted in significant improvements in properties (e.g., short response times and birefringence) that are important for effective beam steering.

Posted in: Briefs, TSP, ptb catchall, Tech Briefs, Photonics, Fiber optics, Optics, Switches, Wireless communication systems, Fiber optics, Optics, Switches, Wireless communication systems

Laser Scanning System Helps Validate Method for Repairing Space Shuttle Heat Shield

SLP-330 Laser Scanning Probe Laser Design
Minneapolis, MN

The loss of the Space Shuttle Columbia because of damage to its thermal protection system (TPS) during launch spurred a search for methods of repairing the TPS in space; specifically, repairing the Reinforced Carbon-Carbon (RCC) material used to protect the nose cap and wing leading edge panels that experience the most extreme heating — more than 3,000° F — during the return to Earth. In testing possible repair methods, it is critical to accurately measure the complex freeform 3D RCC panel shape after the damage, after the repair, and after tests that simulate re-entry. NASA used the SLP-330 laser scanning probe from Laser Design, integrated with Romer portable coordinate measuring machine (CMM) arms for this task.

Posted in: Application Briefs, Lasers & Laser Systems, Imaging, Imaging and visualization, Lasers, Imaging, Imaging and visualization, Lasers, Maintenance, Repair and Service Operations, Maintenance, repair, and service operations, Insulation, Reusable launch vehicles and shuttles

Thermographic Improvements Benefit Automotive Industry

Like most mature industries, the automotive industry is highly competitive. Customers demand quality, security, and economy. Competition requires increasingly fast times to market for new designs. Combining customer and competitive demands creates a dilemma: How to design and build the best product as fast as possible.

Posted in: Articles, Features, ptb catchall, Photonics, Design processes, Thermodynamics, Thermodynamics, Product development, Quality assurance, Quality assurance

Shortwave Infrared (SWIR) Imaging Aids Laser Tracking, Detection

As warfare becomes more asymmetric, civilians and other non-combatants become a larger percentage of the casualties, along with unintended property damage. The military, of course, hopes to avoid these types of casualties and destruction. With advancing technologies that enable more precision from their weapons, they also need better pointing and targeting capabilities, while remaining covert. Improved targeting technologies that allow detection and identification at longer standoff distances from the designators also are needed. For instance, lasers are excellent at precision pointing, but it is important that others be able to covertly image the scene as well.

Posted in: Application Briefs, Applications, ptb catchall, Photonics, Imaging, Imaging and visualization, Lasers, Radio equipment, Surveillance, Imaging, Imaging and visualization, Lasers, Radio equipment, Surveillance, Military vehicles and equipment

Dual-Beam Atom Laser Driven by Spinor Dynamics

A Bose-Einstein condensate is adiabatically compressed to drive coherent spin-mixing evolution.

An atom laser now undergoing development simultaneously generates two pulsed beams of correlated 87Rb atoms. (An atom laser is a source of atoms in beams characterized by coherent matter waves, analogous to a conventional laser, which is a source of coherent light waves.) The pumping mechanism of this atom laser is based on spinor dynamics in a Bose-Einstein beam running-wave dipole trap that has been formed by focusing of a CO2-laser beam. By a technique that is established in the art, the trap is loaded from an ultra-high-vacuum magneto-optical trap that is, itself, loaded via a cold atomic beam from an upstream two-dimensional magneto-optical trap that resides in a rubidium-vapor cell that is differentially pumped condensate. By virtue of the angular-momentum conserving collisions that generate the two beams, the number of atoms in one beam is correlated with the number of atoms in the other beam. Such correlations are intimately linked to entanglement and squeezing in atomic ensembles, and atom lasers like this one could be used in exploring related aspects of Bose-Einstein condensates, and as components of future sensors relying on atom interferometry.

Posted in: Briefs, TSP, ptb catchall, Tech Briefs, Photonics, Architecture, Lasers, Architecture, Lasers, Product development, Pumps

Active Correction of Aberrations of Low-Quality Telescope Optics

Relatively inexpensive optical components could be used in free-space optical communications.

A system of active optics that includes a wavefront sensor and a deformable mirror has been demonstrated to be an effective means of partly correcting wavefront aberrations introduced by fixed optics (lenses and mirrors) in telescopes. It is envisioned that after further development, active optics would be used to reduce wavefront aberrations of about one wave or less in telescopes having aperture diameters of the order of meters or tens of meters. Although this remaining amount of aberration would be considered excessive in scientific applications in which diffraction-limited performance is required, it would be acceptable for free-space optical-communication applications at wavelengths of the order of 1 μm.

Posted in: Briefs, TSP, ptb catchall, Tech Briefs, Photonics, Mirrors, Calibration, Optics, Wireless communication systems, Optics, Wireless communication systems

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

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

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

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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