Quantum-Cascade-Laser-Seeded OPO for DIAL

We propose an all-solid-state, laser-based source that covers the 2.5- to 14-?Ym band and is suitable for use in airborne and space-based differential absorption lidar (DIAL) systems. The proposed DIAL transmitter would enable high-resolution, high-accuracy remote sensing of atmospheric molecular species of interest to NASA including carbon monoxide, carbon dioxide, methane and nitrous oxide as well as many others. To date there have been no sources in this region suitable for NASA DIAL missions. The proposed source is comprised of a diode-laser-pumped, Q-switched, 2-?Ym laser, which pumps a middle-wave-infrared (MWIR) optical parametric oscillator (OPO), that is injection-seeded with a quantum cascade laser (QCL) to provide a narrow linewidth. The primary innovation is the use of recently developed distributed feedback (DFB) QCLs to injection-seed a MWIR OPO for the purpose of obtaining narrow linewidth, high-pulse-energy operation in a compact, simple configuration. A secondary innovation is the specific selection of other critical system components that make the overall system suitable for airborne and space-based instrumentation. These include the all-solid-state 2-?n?Ym pump laser and the MWIR OPO, which can be constructed with either zinc germanium phosphide (ZGP) or cadmium selenide (CdSe) depending on the wavelength coverage desired.