Broadly Tunable Quantum Cascade Laser Technology for Remote Sensing

National security interests related to the nonproliferation of weapons of mass destruction require the remote detection of trace gases associated with the nuclear fuel cycle. Newly developed, mid-infrared, quantum cascade lasers have the potential to contribute to this application. These small solid state lasers produce relatively high power in the infrared band of light where many gases can be most sensitively detected, and without the usual need for extreme cooling. However, the tuning range of these lasers needs improvement, in order to allow more gases to be detected. To develop a widely tunable quantum cascade laser, this project will design an external cavity laser light source based on a quantum cascade gain medium. A "coupled-cavity tuning" technique will be employed to compensate for the usual technical limitations of such laser designs, thereby achieving wide and uniform emission tuning. During Phase I, the small business will perform remote sensing experiments with currently-available quantum cascade lasers, in order to guide the development of instrument optics, software, and robust integrated designs. Then, the research institution will further develop the coupled-cavity tuning technique to produce a widely-tuning laser module, which will be added to a remote sensing module during Phase II. Commercial Applications and other Benefits as described by the awardee: The development of broadly-tunable quantum-cascade technology for remote sensing should have widespread applications in both the commercial and government sectors. Commercial applications include remote pipeline leak detection, remote trace gas detection for agriculture, industrial emissions monitoring, and environmental science. Security-related government applications include the remote inspection of shipping containers, monitoring industrial facilities for evidence of prohibited chemicals, or sensing battlefield chemical weapons.