Portable and Inexpensive Chemical and Biological Sensors

Summary The broadly tunable quantum cascade laser (QCL) described in this invention enables the production of a small, portable chemical and biological sensor that can detect a range of molecules within a single, compact device. Quantum Cascade Lasers (QCLs) are intraband semiconductor lasers that can emit within the mid-infrared and terahertz spectral regions, in particular, the molecular ‘fingerprint’ range where many molecules have tell-tale absorptions. The broadly tunable QCL uses include, environmental monitoring, high-resolution spectroscopy, breath analysis for medical diagnostics, remote sensing, homeland security, infrared detection, countermeasures, and many other applications. Harvard’s QCL source can be used in portable broadband sensors to simultaneously detect a large number of compounds including chemical and biological agents. This invention can be used in any application that requires a high-power, narrow-linewidth, broadly tunable source in the mid-infrared. For example, the laser source can be integrated into a microfluidic infrared spectrometer or into extremely sensitive gas sensors.

Applications The invention is a novel design for a broadly tunable single-mode infrared laser source based on quantum cascade lasers. The laser source has two parts: an array of closely-spaced distributed feedback QCLs and a controller which can switch each of the individual lasers in the array on and off, set current for each of the lasers, and control the temperature (and thus the emission wavelength) of the lasers in the array. The broadly tunable single-mode QCL source offers a number of advantages over the external grating broadly tunable QCLs. The performance (tuning range, line width, power level) is comparable to that of external grating tunable semiconductor lasers, but the design is much smaller and much easier to manufacture. The packaging cost is much lower, as there is no need for careful alignment of the lasers and optics. In addition, our QCL source offers better temperature performance and higher output powers than external grating broadly tunable QCLs. For Further Information Please Contact the Director of Business Development Alan Gordon Email: alan_gordon@harvard.edu Telephone: (617) 384-5000

Inventor(s): Capasso, Federico

Type of Offer: Licensing

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