Wisconsin Alumni Research Foundation

Alfalight Inc.

Thomas L Earles

Dan Botez

Luke J Mawst

Christopher A Sigler

Jeremy Daniel Kirch

Henry Guckel

Jonathan L Klein

Eric Warren Stiers

Manoj Kanskar

Single-mode quantum cascade semiconductor lasers are provided. The lasers comprise a laser element, the laser element comprising a quantum cascade active layer; an upper cladding layer over the quantum cascade active layer; and a lower cladding layer under the quantum cascade active layer, wherein the quantum cascade active layer, the upper cladding layer and the lower cladding layer define a guided optical mode. The quantum cascade active layer and the upper and lower cladding layers are shaped in the form of a ridge structure having a front face, a back face opposite the front face, and a lasing face through which laser emission exits the ridge structure, the ridge structure configured such that the laser emission has a single-lobe, far-field beam pattern from the ridge structure comprising certain sections, including tapered sections, collateral sections, or both.

High-power, single-spatial-mode quantum cascade lasers

A terahertz quantum cascade laser device is provided comprising a substrate having a top substrate surface, a bottom substrate surface, and an exit facet extending between the top substrate surface and the bottom substrate surface at an angle &#x3b8;. The device comprises a waveguide structure having a top surface, a bottom surface, a front facet extending between the top surface and the bottom surface and positioned proximate to the exit facet, and a back facet extending between the top surface and the bottom surface and oppositely facing the front facet. The waveguide structure comprises a quantum cascade laser structure configured to generate light comprising light of a first frequency &#x3c9;, light of a second frequency &#x3c9;, and light of a third frequency &#x3c9;, wherein &#x3c9;=&#x3c9;&#x2212;&#x3c9;; an upper cladding layer; and a lower cladding layer. The device comprises a distributed feedback grating layer configured to provide optical feedback for one or both of the light of the first frequency &#x3c9;and the light of the second frequency &#x3c9;and to produce lasing at one or both of the first frequency &#x3c9;and the second frequency &#x3c9;, thereby resulting in laser emission at the third frequency &#x3c9;at a Cherenkov angle &#x3b8;through the bottom surface of the waveguide structure into the substrate and exiting the substrate through the exit facet. The device comprises a high-reflectivity coating on the front facet of the waveguide structure.

Terahertz quantum cascade lasers

Semiconductor lasers comprise a substrate; an active layer configured to generate transverse magnetic (TM) polarized light under an electrical bias; an upper cladding layer; a lower cladding layer; and a distributed feedback (DFB) grating defined by the interface of a layer of metal and a layer of semiconductor under the layer of metal, the interface periodically corrugated in the longitudinal direction of the laser with a periodicity of &#x39b;=m&#x3bb;/(2n), wherein m&#x3e;1. The DFB grating is configured such that loss of one or more antisymmetric longitudinal modes of the laser structure via absorption to the DFB grating is sufficiently maximized so as to produce lasing of a symmetric longitudinal mode of the laser with laser emission characterized by a single-lobe beam along each direction defined by the grating diffraction orders corresponding to emission away from the plane of the grating.

Substrate-emitting transverse magnetic polarized laser employing a metal/semiconductor distributed feedback grating for symmetric-mode operation

A semiconductor laser diode comprises a p-n junction. The p-n junction comprises a substrate, an n-type semiconductor layer, a p-type semiconductor layer, and a quantum well. The quantum well is disposed between the n-type semiconductor layer and the p-type semiconductor layer. The substrate is formed from a first material system, the n-type semiconductor layer is formed from a second material system, the p-type semiconductor layer is formed from a third material system, and the quantum well is formed from a fourth material system. The second material system is different from the third material system. The second material system and the third material system are selected such that there is an increase in the rate of recombinations of the electrons from the n-type semiconductor layer and the holes from the p-type semiconductor layer in the quantum well. This results in a lower turn-on voltage for the semiconductor laser diode.

Semiconductor laser diode

High power edge emitting semiconductor lasers are formed to emit with very narrow spectral width at precisely selected wavelengths. An epitaxial structure is grown on a semiconductor substrate, e.g., GaAs, and includes an active region at which light emission occurs, upper and lower confinement layers and upper and lower cladding layers. A distributed feedback grating is formed in an aluminum free section of the upper confinement layer to act upon the light generated in the active region to produce lasing action and emission of light from an edge face of the semiconductor laser. Such devices are well suited to being formed to provide a wide stripe, e.g., in the range of 50 to 100 &mgr;m or more, and high power, in the 1 watt range, at wavelengths including visible wavelengths.

Narrow spectral width high power distributed feedback semiconductor lasers

Narrow spectral width high-power distributed feedback semiconductor lasers

Micromechanical structures capable of actuation for purposes such as fluid flow control are formed on substrates in sizes in the range of one or two millimeters or less using micromechanical processing techniques. A magnetic core having a gap therein is fixed on the substrate, and a plunger is mounted by a spring for movement parallel to the substrate in response to the flux provided to the gap of the fixed core. An electrical coil wound around a mandrel is engaged to the fixed magnetic core such that flux is induced in the core when current is supplied to the coil, driving the plunger against the force of the spring. A micromechanical fluid control unit includes a metal frame structure formed by electrodeposition on a substrate with the inner wall of the frame having slots formed therein to admit a separator wall which divides the interior of the frame into separate chambers, with a cover secured over the top of the frame and the separator wall to seal the chambers. A plunger actuator can be mounted within the frame with fixed core sections extending through the walls of the frame, and with the mandrel and coil engaged to the fixed core sections outside of the frame to provide magnetic flux to a gap to actuate the plunger within the sealed enclosure.

Growing community of inventors

Verona, WI, United States of America

Thomas L Earles