A laser cavity formed from a single defect in a two-dimensional photonic crystal is demonstrated. The optical microcavity consists of a half wavelength–thick waveguide for vertical confinement and a two-dimensional photonic crystal mirror for lateral localization. A defect in the photonic crystal is introduced to trap photons inside a volume of 2.5 cubic half-wavelengths, approximately 0.03 cubic micrometers. The laser is fabricated in the indium gallium arsenic phosphide material system, and optical gain is provided by strained quantum wells designed for a peak emission wavelength of 1.55 micrometers at room temperature. Pulsed lasing action has been observed at a wavelength of 1.5 micrometers from optically pumped devices with a substrate temperature of 143 kelvin.

https://science.sciencemag.org/content/sci/284/5421/1819.full.pdf

Two-Dimensional Photonic Band-Gap Defect Mode Laser

Organic semiconductor lasers.

An imaging system for a vehicle includes an imaging device having a field of view exteriorly and forward of the vehicle in its direction of travel, and an image processor operable to process the captured images in accordance with an algorithm. The algorithm comprises a sign recognition routine and a character recognition routine. The image processor processes the image data captured by the imaging device to detect signs in the field of view of the imaging device and applies the sign recognition routine to determine a sign type of the detected sign. The image processor is operable to apply the character recognition routine to the image data to determine information on the detected sign. The image processor applies the character recognition routine to the captured images in response to an output of the sign recognition routine being indicative of the detected sign being a sign type of interest.

Imaging system for vehicle

A rearview vision system (12) for a vehicle includes at least one image capture device (16) directed rearwardly with respect to the direction of travel of the vehicle. A display system (20) displays an image synthesized from output of the image capture device. The display system is preferably contiguous with the forward field of view of the vehicle driver at a focal length that is forward of the vehicle passenger compartment. A plurality of image capture devices (14, 16) may be provided and the display system displays a unitary image synthesized from outputs of the image capture devices which approximates a rearward-facing view from a single location, such as forward of the vehicle.

Rearview vision system for vehicle including panoramic view

A personal digital assistant (PDA) (10) stores data from physiological monitors (12) so that the data can be used in various software applications. In different embodiments the physiological monitor (12) can include data storage or have memory modules that are accepted by accessory slots (48 and 50).

Physiological monitor and associated computation, display and communication unit

A vertical-cavity surface-emitting laser is disclosed comprising a laser cavity sandwiched between two distributed Bragg reflectors. The laser cavity comprises a pair of spacer layers (20, 40) surrounding one or more active, optically emitting quantum-well layers (30) having a bandgap in the visible which serve as the active optically emitting material of the device. The thickness of the laser cavity is m μ/2neff where m is an integer, μ is the free-space wavelength of the laser radiation and neff is the effective index of refraction of the cavity. Electrical pumping of the laser is achieved by heavily doping the bottom mirror (10) and substrate (60) to one conductivity-type and heavily doping regions of the upper mirror (50) with the opposite conductivity type to form a diode structure and applying a suitable voltage to the diode structure. Specific embodiments of the invention for generating red, green, and blue radiation are described.

Red light surface emitting semiconductor laser

Quantum-Well-Laser mit vertikalem Resonator

Oberflächenemittierender laser für sichtbares licht

Thermal management is critical to reliable optoelec- tronic modules based on vertical-cavity surface-emitting lasers WCSEL's). One critical thermal path to be managed is from a VCSEL to a case (heat sink), which is affected by packaging tech- nologies and materials. The measured VCSEL-to-case resistance of a laser with 8-pm aperture was 1650 "CNV, and that of a 20- pm device was 1070 "CNV. These thermal resistances are much larger than those for the edge-emitting lasers. Advanced device and packaging technologies are being developed to reduce these resistances. To study the packaging effects, a three-dimensional (3-D) numerical model has been developed and calibrated by the measured data. The calibrated model was used to understand the difference in thermal behavior: 1) between a wire-bonded and a flip-chip VCSEL module, 2) between a single-VCSEL and an 8 x 8 VCSEL module, and 3) between a bottom-cooled and a top-cooled module. Index Terms-VCSEL, thermal management, flip-chip, model- ing.

Thermal Management of ased Optoelectronic

L'invention se rapporte a un systeme d'affichage utilisant des groupements uni- et/ou bidimensionnels de lasers a cavite verticale et a emission de surface visible (VCSELs)(200) afin de produire un affichage visuel requis dans le champ de vision (220) d'un observateur. Des techniques de balayage et de sous-exploration sont utilisees, individuellement ou en combinaison, pour creer une image M x N complete a partir de 1 x L ou K x L groupements de VCSELs, M et N etant des entiers multiples de K et de L respectivement. Le VCSELs (200) sont de preference contenus dans un boitier d'affichage qui peut etre fixe a la tete de l'utilisateur par un mecanisme de fixation ou qui peut, selon une variante, etre tenu a la main ou monte sur une surface. La symetrie circulaire et la faible divergence du rayonnement de VCSEL emis, ainsi que la disponibilite de longueurs d'ondes multiples, en particulier rouge, bleu et vert, permettent de produire des images monochromes ou couleurs de haute resolution.

Jack L. Jewell

Papers

Red light surface emitting semiconductor laser

Quantum-Well-Laser mit vertikalem Resonator

Oberflächenemittierender laser für sichtbares licht

Thermal Management of ased Optoelectronic

Systeme d'affichage a groupement de lasers a cavite verticale et a emission de surface