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

The authors have designed, fabricated, and tested vertical-cavity surface-emitting lasers (VCSEL) with diameters ranging from 0.5 mu m to>50 mu m. Design issues, molecular beam epitaxial growth, fabrication, and lasing characteristics are discussed. The topics considered in fabrication of VCSELs are microlaser geometries; ion implementation and masks; ion beam etching packaging and arrays, and ultrasmall devices. >

/pdf/vertical-cavity-surface-emitting-lasers-design-growth-vwch8uf5pf.pdf

Vertical-cavity surface-emitting lasers: Design, growth, fabrication, characterization

A visual display system is disclosed which utilizes one- and/or two-dimensional arrays of visible emitting vertical-cavity surface-emitting lasers (VCSELs) in order to provide a desired visual display within an observer's field of view. Sweep and subscanning techniques are employed, individually or in combination, to create a full M×N image from 1×L or K×L arrays of VCSELs, where M and N are multiple integers of K and L, respectively. Preferably, the VCSELs are contained within a display housing which may be attached to the head of the user by an attachment mechanism or may alternatively be hand held or mounted to a surface. The circular symmetry and low divergence of the emitted VCSEL radiation as well as the availability of multiple wavelengths, particularly, red, blue and green, allow high resolution monochrome or color images to be generated.

Vertical-cavity surface emitting laser assay display system

Vertical-cavity electrically driven lasers with three GaInAs quantum wells and diameters of several μm exhibit roomtemperature pulsed current thresholds as low as 1·3mA with 958 nm output wavelength.

Low-Threshold Electrically Pumped Vertical Cavity Surface-Emitting Microlasers

Room-temperature continuous and pulsed lasing of vertical-cavity, single-quantum-well, surface-emitting microlasers is achieved at ~983nm. The active Ga[sub][0-8]In[sub][0-2]As single quantum well is 100 [angstroms] thick. These microlasers have the smallest gain medium volumes among lasers ever built. The entire laser structure is grown by molecular beam epitaxy and the microlasers are formed by chemically assisted ion-beam etching. The microlasers are 3-50-μm across. The minimum threshold currents are 1.1 mA (pulsed) and 1.5 mA (CW).

/pdf/room-temperature-continuous-wave-vertical-cavity-single-3orbzsz4iq.pdf

Room-Temperature Continuous-Wave Vertical-Cavity Single-Quantum-Well Microlaser Diodes

A vertical-cavity, surface-emitting semiconductor diode laser having a monolithic and planar surface and having lateral anisotropy in order to control the polarization of the emitted beam of light. The diode laser includes a body of a semiconductor material having an active region therein which is adapted to generate radiation and emit the radiation from a surface of the body, and a separate reflecting mirror at opposite sides of the active region with at least one of the mirrors being partially transparent to the generated light to allow the light generated in the active region to be emitted therethrough. The anisotropy may be provided by utilizing anisotropy in the atomic or molecular structure of the materials forming the laser, or by anisotropic patterning or deliberate offset alignment in processing of the laser or through anisotropic structures in the laser cavity to control the polarization of the emitted beam.

Jack L. Jewell

Papers

Vertical-cavity surface-emitting lasers: Design, growth, fabrication, characterization

Vertical-cavity surface emitting laser assay display system

Low-Threshold Electrically Pumped Vertical Cavity Surface-Emitting Microlasers

Room-Temperature Continuous-Wave Vertical-Cavity Single-Quantum-Well Microlaser Diodes

Polarized surface-emitting laser