Home

Digital Beam Deflectors Based Partly on Liquid Crystals

Laser beams are switched to different directions, without using solid moving parts. John H. Glenn Research Center, Cleveland, Ohio 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: Tech Briefs, ptb catchall, Photonics, Briefs

Read More >>

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: Features, ptb catchall, Photonics, Articles

Read More >>

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: ptb catchall, Applications, Photonics, Application Briefs

Read More >>

Dual-Beam Atom Laser Driven by Spinor Dynamics

A Bose-Einstein condensate is adiabatically compressed to drive coherent spin-mixing evolution. NASA’s Jet Propulsion Laboratory, Pasadena, California 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: Tech Briefs, ptb catchall, Photonics, Briefs

Read More >>

Active Correction of Aberrations of Low-Quality Telescope Optics

Relatively inexpensive optical components could be used in free-space optical communications. NASA’s Jet Propulsion Laboratory, Pasadena, California 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: Tech Briefs, ptb catchall, Photonics, Briefs

Read More >>

Rugged, Tunable Extended-Cavity Diode Laser

This laser is relatively insensitive to vibration. NASA’s Jet Propulsion Laboratory, Pasadena, California 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: Tech Briefs, ptb catchall, Photonics, Briefs

Read More >>

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: Features, ptb catchall, Photonics, Articles

Read More >>