Research Terms
Researchers at the University of Central Florida have invented a quantum cascade laser (QCL) that provides the ultra-high output power, brightness, and beam quality needed for broad-area applications. Example applications include hyperspectral imaging, infrared illumination, and military countermeasures that protect aircrafts against shoulder-fired heat-seeking missiles. Key to the invention is an ultra-thin active region with low thermal resistance and the ability to use angled grating distributed feedback (a-DFB) configurations.
The invention consists of an a-DFB QCL device and fabrication methods. It comprises a substrate, one or more emitting facets, and semiconductor layers forming an ultra-thin active region that dramatically reduces thermal resistance. Also included is a shallow ridge or simple contact-strip configuration to suppress mode reflection at the lateral active region/waveguide interface and an a-DFB grating for spatial mode selection. The new QCL can emit continuous-wave laser output or a pulsed laser output through the emitting facet. Multiple QCLs combined into a W-shaped array can reach optical power levels above 100W into a high brightness beam.
Researchers at the University of Central Florida have designed a compact, lightweight quantum cascade laser (QCL) that can maintain beam quality and protect against laser facet damage while achieving more than 30 watts of optical power from a single emitter. With such capabilities and continuous-wave (CW) optical power scalability, the new UCF design offers higher performance and efficiency for broad-area applications in the mid_wave and long_wave infrared (MWIR/LWIR) regions. For example, the invention?s unique combination of size, weight and power enables its use as an effective defensive countermeasure against shoulder_fired heat_seeking missiles and other weapons that use focal plane arrays to target and destroy aircraft.
Technical Details
The UCF invention comprises a broad_area QCL design for CW optical power scalability and a method of making the QCL, including details for specific device dimensions, configurations, energy specifications and materials. The new design provides for a larger active region depth and injector coupling than either single-phonon, double-phonon or non-resonant extraction designs. In contrast to the bound-to-continuum design, it uses a vertical laser transition. The design also includes a concept for laser packaging that protects against laser facet damage from heating. For example, using the new packaging concept, a device manufacturer could independently collect optical power emitted from two laser facets and then recombine the two beams using one of many possible beam-combining approaches, such as spatial beam combining (placing the two beams close to each other) and polarization beam combining.
In one example configuration, the QCL includes a substrate, a sequence of semiconductor epitaxial layers that define an active region, an injector region, and a waveguide that is optically coupled to the active region. The active region may include multiple stages, with each stage having an upper laser level and a lower laser level to defining respective first and second wave functions.
Partnering Opportunity
The research team is looking for partners to develop the technology further for commercialization.
The University of Central Florida invention is an optimized mid-infrared quantum cascade laser (QCL) design capable of delivering multi-watt continuous wave (CW) power in a high-quality output beam. The design comprises InP spacers whose thickness, as well as other design parameters, is adjusted to simultaneously achieve a high CW power and high beam quality. The design method uses a semi-empirical model to predict CW performance for a QCL configuration can serve as a critical tool for the QCL performance optimization without the need to fabricate and test each proposed device. Applications include infrared countermeasures, infrared beacons and target designators, infrared illumination, hyperspectral imaging, plasmonics, and metamaterials.
The University of Central Florida invention describes a quantum cascade laser (QCL) configuration with broad-area emitters and tapers at the output facet. The configuration potentially offers ultra-high brightness with on-axis, far-field maximum, and most power concentrated in the central lobe. Broad-area quantum cascade lasers are capable of delivering very high CW power. Output beams from several broad-area emitters can be coherently combined into a single very high brightness beam employing the tree array configuration. The tree array devices are projected to have high yield; they can therefore be commercialized for employment in various critical Department of Defense (DOD) infrared applications.
The University of Central Florida invention is a quantum cascade laser (QCL) that uses waveguides with a continuously varying curvature to combine multiple inputs into a single output for increased brightness. The beam-combining configuration can produce multi-watt continuous wave (CW) optical power with a high beam quality. Using a novel waveguide architecture, the invention selects fundamental transverse mode operation in a tree-array quantum cascade laser.
Technical Details: The waveguides in the UCF technology are sufficiently sized to support multiple optical modes at the output wavelengths, and curved waveguide regions have a continuously varying radius of curvature configured to promote single-mode operation. The mode-selective aspect of the waveguide architecture enables wider ridge waveguides to maintain fundamental transverse mode operation at higher output powers. Fundamental mode operation, particularly near the emitting facet of the laser, enables a beam of high quality and brightness.
In some embodiments of the invention, the QCL may include multiple branched active waveguide regions, a stem waveguide region, and waveguide connectors to progressively couple light from the branched active waveguide regions to the stem waveguide region. The branched active regions may each include one or more laser cores formed as multilayer quantum cascade (QC) media and may be wide and/or deep enough to support multi-mode propagation at output wavelengths.
Partnering Opportunity: The research team is seeking partners for licensing, research collaboration, or both.
