High Power, Mid-Infrared Fiber Supercontinuum Light Source

Modern supercontinuum (SC) light sources are generated by non-linear interactions between ultrashort pulse lasers and optical fibers. Output in near-ultraviolet to near-infrared wavelength ranges has been demonstrated. These light sources have high brightness and are spatially coherent. Recently, output to 4.5 µm was achieved using fluoride glass fibers; optical absorption by the fiber prevents longer wavelength output. Challenges to extending SC sources to the mid-IR (out to 12µm) are the development of low-loss fiber materials (propagation in conventional glass fibers is limited by material absorption), the development of new, highly nonlinear materials, and designs that allow for mode confinement within the fiber. Mesa Photonics, LLC, and Prof. Fiorenzo Omenetto of Tufts University propose development of mid-infrared supercontinuum sources based on newly available optical fibers. Our goal is the development of a spatially coherent SC source operable in the 4.5-12 µm spectral region with an output power exceeding 100 mW in a band at least 800 cm-1 wide and a minimum power per unit bandwidth of 0.125 mW/cm -1. In Phase 1 we will characterize mid-infrared generation and demonstrate a simple application by acquiring molecular absorption spectra using the SC source.