Wisconsin Alumni Research Foundation

Jeremy Daniel Kirch

Dan Botez

Luke J Mawst

Thomas L Earles

Christopher A Sigler

Thomas Francis Kuech

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

Semiconductor structures, quantum cascade structures and lasers including the structures are provided. The semiconductor structures include a substrate, a metamorphic buffer layer structure over the substrate, and a quantum cascade structure including a superlattice of quantum wells and barriers over the metamorphic buffer layer structure. The substrate may be GaAs and the quantum cascade structure may be an InGaAs/InAlAs superlattice, including one or more barriers of AlAs.

Quantum cascade structures on metamorphic buffer layer structures

Semiconductor laser array devices capable of emitting mid- to long-wavelength infrared (i.e., 4-12 &#x3bc;m) radiation are provided. The devices include a quantum cascade laser (QCL) structure comprising one or more active cores; an optical confinement structure; a cladding structure, and a plurality of laterally-spaced trench regions extending transversely through the cladding and optical confinement structures, and partially into the QCL structure. The trench regions define a plurality of laterally-spaced interelement regions separated by element regions in the laser array device. The element regions are characterized by a non-uniform structure across their widths. As a result of this structural non-uniformity, array modes composed of coupled first-order lateral modes of the element regions are preferentially suppressed relative to array modes composed of coupled fundamental lateral modes of the element regions.

Growing community of inventors

Middleton, WI, United States of America

Jeremy Daniel Kirch