Wisconsin Alumni Research Foundation

Christopher A Sigler

Dan Botez

Thomas L Earles

Luke J Mawst

Jeremy Daniel Kirch

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.

Growing community of inventors

Madison, WI, United States of America

Christopher A Sigler