MID-IR OPTICS: Fluoride glasses draw fiber into the mid-infrared

摘要

The properties of fluoride glass enable fiber to transmit light from the UV to the mid-IR, wavelengths where silica's high absorption has limited its use. Fluoride glasses comprise a unique infrared amorphous material system that can be drawn into optical fibers and that transmits light from the ultraviolet to the mid-IR wavelengths without any absorption peak. Many properties of fluoride glass set it apart from other materials such as silica. Because silica glass becomes highly absorbing above 2 (mu)m, fluoride glass is the material of choice for numerous mid-IR applications such as laser-beam delivery, sensing, pyrometry, and spectroscopy, in fields as diverse as medicine, defense, and astronomy. Fiber lasers with narrow emission lines in the visible and the infrared can also be made using fluoride glass because it can be doped with high concentrations of rare-earth elements.