Infrared-Transmitting Fibers

Abstract : Chalcogenide glass fibers have been fabricated with minimum optical loss of 0.23 dB/m in the 1 - 6 mm region. NRL reports on results of applications of these fibers including IRCM and chemical sensing. For IRCM, they have demonstrated high power transmission through selected fibers using an Optical Parametric Oscillator with output in the 3 - 5 mm wavelength region. The maximum peak power used was 26.9 kW and the peak power density at the focus into the fiber was 1.07 GW/cm2, which to NRL's knowledge is the highest reported for these types of fibers. Analysis of the near field profile exiting the fibers showed that there was no speckle observed, which is highly desirable for this application. For chemical sensing, results of infrared reflectance spectroscopy and evanescent spectroscopy will be described wherein the application is the detection of toxic chemicals in soil or ground water.