Applications
Distributed feedback (DFB) quantum cascade lasers were first commercialized in 2004, and broadly-tunable external cavity quantum cascade lasers first commercialized in 2006. The high optical power output, tuning range and room temperature operation make QCLs useful for spectroscopic applications such as remote sensing of environmental gases and pollutants in the atmosphere and homeland security. They may eventually be used for vehicular cruise control in conditions of poor visibility, collision avoidance radar, industrial process control,and medical diagnostics such as breath analyzers. QCLs are also used to study plasma chemistry.
Their large dynamic range, excellent sensitivity, and failsafe operation combined with the solid-state reliability should easily overcome many of the technological hurdles that impede existing technology in these markets. When used in multiple-laser systems, intrapulse QCL spectroscopy offers broadband spectral coverage that can potentially be used to identify and quantify complex heavy molecules such as those in toxic chemicals, explosives, and drugs.
Unguided QCL emission in the 3–5 μm atmospheric window could be used as a cheaper alternative to optical fibres for high-speed Internet access in built up areas.
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