Unlike fused silica and oxyfluoride glasses that cannot survive in some harsh environments, a new transparent ceramic for high-energy laser (HEL) systems developed at the US Naval Research Laboratory (NRL; Washington, DC) can withstand impact from rain droplets at 600 mph and sand particles at speeds up to 460 mph with no change in transmission parameters.
The transparent magnesium aluminate spinel (MgAl2O4) ceramic, developed as a window and dome material for protecting sensors operating from the UV to the mid-IR region to 5 µm, was designed with optimized low absorption loss of 6 ppm/cm to minimize the beam distortions and loss of output power that are measured as optical-path distortions in HEL systems. The ceramic spinel was made by hot-pressing ball-milled spinel powders at 1400–1650ºC for 2–4 hours using a uniform coating of a small amount of lithium fluoride sintering aid that was eliminated by evaporation prior to full densification. The NRL spinel powder (synthesized by an aqueous process) had crystallites 100–200 nm in size with excellent phase purity based on x-ray diffraction and chemical analysis, with an impurity content several orders of magnitude lower than commercially available spinel powders. Contact Jas Sanghera at [email protected].
Gail Overton | Senior Editor (2004-2020)
Gail has more than 30 years of engineering, marketing, product management, and editorial experience in the photonics and optical communications industry. Before joining the staff at Laser Focus World in 2004, she held many product management and product marketing roles in the fiber-optics industry, most notably at Hughes (El Segundo, CA), GTE Labs (Waltham, MA), Corning (Corning, NY), Photon Kinetics (Beaverton, OR), and Newport Corporation (Irvine, CA). During her marketing career, Gail published articles in WDM Solutions and Sensors magazine and traveled internationally to conduct product and sales training. Gail received her BS degree in physics, with an emphasis in optics, from San Diego State University in San Diego, CA in May 1986.