A proximity sensor which uses very narrow divergent beams from Vertical Cavity Surface Emitting Laser (VCSEL) for the illumination source is disclosed. Narrow divergent beams in the range 0.5 to 10 degrees can be achieved to provide high proximity sensing accuracy in a small footprint assembly. One approach to reducing the beam divergence is to increase the length of the VCSEL resonant cavity using external third mirror. A second embodiment extends the length of the VCSEL cavity by modifying the DBR mirrors and the gain region. Optical microlenses can be coupled with the VCSEL to collimate the output beam and reduce the beam divergence. These can be separate optical elements or integrated with the VCEL by modifying the substrate output surface profile or an added a transparent layer. These methods of beam divergence reduction are incorporated into various embodiment configurations to produce a miniature proximity sensor suitable for cell phones and tablets.

A CO.sub.2 laser that generates laser-radiation in just one emission band of a CO.sub.2 gas-mixture has resonator mirrors that form an unstable resonator and at least one spectrally-selective element located on the optical axis of the resonator. The spectrally-selective element may be in the form of one or more protruding or recessed surfaces. Spectral-selectivity is enhanced by forming a stable resonator along the optical axis that includes the spectrally-selective element. The CO.sub.2 laser is tunable between emission bands by translating the spectrally-selective element along the optical axis.

Materials, method of making and methods of using a composite laser for producing multiple temporal ignition pulses. The composite laser includes a pump source forming an optical path in an active media in a cavity of the laser; and a Q-switched material located in a center of a rod in communication with the active media and blocking a portion of the active media.

A CO.sub.2 laser that generates laser-radiation in just one emission band of a CO.sub.2 gas-mixture has resonator mirrors that form an unstable resonator and at least one spectrally-selective element located on the optical axis of the resonator. The spectrally-selective element may be in the form of one or more protruding or recessed surfaces. Spectral-selectivity is enhanced by forming a stable resonator along the optical axis that includes the spectrally-selective element. The CO.sub.2 laser is tunable between emission bands by translating the spectrally-selective element along the optical axis.

The present invention relates to a diode laser with external spectrally selective feedback. It is an object of the invention is to provide an external cavity diode laser with wavelength stabilization which allows an increased overall output power in the desired wavelength range. According to the invention, an external cavity diode laser arrangement is disclosed comprising: an active medium positioned inside an internal laser cavity (10), the internal laser cavity (10) comprising an exit facet (12) adapted for outcoupling laser radiation; an external frequency-selective element (14) positioned outside the internal laser cavity (10) and adapted for wavelength stabilization of the laser radiation; a beam divider (16) positioned outside the internal laser cavity (10) and adapted to divide the outcoupled laser radiation (BO) into a first beam (B1) extending along a first beam path (P1) and a second beam (B2) extending along a second beam path (P2), the first beam (B1) having higher radiant intensity than the second beam (B2) and the first beam path (P1) being different from the second beam path (P2); and an intensity control means to control the radiant intensity incident to the external frequency selective element (14); wherein the external frequency-selective element (14) and the intensity control means are arranged in the second beam path (P2). The intensity control means in the second beam path (P2) may comprise a polarization modifying means (18) and a polarizer (20) in order to reduce thermal stress at the frequency-selective element (14).

The present invention relates to a diode laser with external spectrally selective feedback. It is an object of the invention is to provide an external cavity diode laser with wavelength stabilization which allows an increased overall output power in the desired wavelength range. According to the invention, an external cavity diode laser arrangement is disclosed comprising: an active medium positioned inside an internal laser cavity (10), the internal laser cavity (10) comprising an exit facet (12) adapted for outcoupling laser radiation; an external frequency-selective element (14) positioned outside the internal laser cavity (10) and adapted for wavelength stabilization of the laser radiation; a beam divider (16) positioned outside the internal laser cavity (10) and adapted to divide the outcoupled laser radiation (BO) into a first beam (B1) extending along a first beam path (P1) and a second beam (B2) extending along a second beam path (P2), the first beam (B1) having higher radiant intensity than the second beam (B2) and the first beam path (P1) being different from the second beam path (P2); and an intensity control means to control the radiant intensity incident to the external frequency selective element (14); wherein the external frequency-selective element (14) and the intensity control means are arranged in the second beam path (P2). The intensity control means in the second beam path (P2) may comprise a polarization modifying means (18) and a polarizer (20) in order to reduce thermal stress at the frequency-selective element (14).

The subject invention includes a semiconductor laser with the laser having a DBR mirror on a substrate, a quantum well on the DBR mirror, and an interior CGH with a back propagated output for emitting a large sized Gaussian and encircling high energy. The DBR mirror has a plurality of GaAs/AlGaAs layers, while the quantum well is composed of AlGaAs/InOaAs. The CGH is composed of AlGaAs.

A new optically pumped far infrared (FIR) laser with separate pump beam reflector and FIR output coupler is developed. The configuration of the new FIR laser greatly simplifies the tuning of the laser and enables the optimization of the pump beam absorption without affecting the laser alignment.

The subject invention includes a semiconductor laser with the laser having a DBR mirror on a substrate, a quantum well on the DBR mirror, and an interior CGH with a back propagated output for emitting a large sized Gaussian and encircling high energy. The DBR mirror has a plurality of GaAs/AlGaAs layers, while the quantum well is composed of AlGaAs/InGaAs. The CGH is composed of AlGaAs.

A new optically pumped far infrared (FIR) laser with separate pump beam reflector and FIR output coupler is developed. The configuration of the new FIR laser greatly simplifies the tuning of the laser and enables the optimization of the pump beam absorption without affecting the laser alignment.