Infrared materials and fiber optics

Summary form only given. At the Naval Research Laboratory (NRL), we are developing infrared glasses, ceramics and optical fibers for many active and passive applications. The chalcogenide glasses transmit from approximately 1 μm to 12 μm in the important infrared wavelength region. Fibers have been developed for passive applications, including light-pipes for remote chemical sensor systems for environmental pollution monitoring, exo-planet discovery, scanning near field optical microscopy and aircraft protection systems. Active applications have also been developed to exploit the high optical nonlinearity of the fibers to generate broadband IR supercontinuum sources and Raman wavelength shifters. In addition, rare earth doping has been used to create bright sources in the IR for applications such as dynamic IR scene projection systems. More recent developments have focused on fabricating hollow core negative curvature fiber with waveguide loss 100X lower than the material loss in the infrared. Additionally fiber devices and components have been designed and fabricated. Examples include IR fiber combiners utilized to couple the output from several QCLs in the MWIR and LWIR into a single output fiber, thereby enabling efficient power and wavelength scaling. Robust splicing between different types of fibers has also been demonstrated.We have also developed new ceramic materials with superior thermal and mechanical properties such as spinel ceramic for window and dome applications. By synthesising high purity powder, we have fabricated ceramic windows with ultra low absorption loss for exit apertures on high energy laser systems. Similarly, rare earth doped Lutetia and Yttria nano-powders have been hot pressed into transparent ceramic laser materials which exhibit record high slope efficiencies.