Moldable glass spectrally spans from UV to mid-IR

Although moldable glasses that span the long-wavelength IR (6 µm and longer) and UV-to-near-IR range (0.3 to 2 µm) are available, moldable glasses extending out to mid-IR wavelengths of 2 to 6 µm are more difficult to manufacture because of multiphonon absorption and the presence of water that causes hydroxide (OH) impurities. But by using fluoride glasses-with losses at least one order of magnitude lower than competing technologies-and by developing a new glass-synthesis process with minimal impurities and a very low OH content, IRphotonics (Montreal, QC, Canada) developed a “UVIR” amorphous glass that can be molded into a variety of optical components (including aspherical lenses) and that achieves over 91% transmission from 350 nm to 5 µm and more than 80% transmission from 220 nm to 6.2 µm.

This glass also exhibits a negative dn/dT (a decrease in refractive index with rising temperature) and a thermal-expansion coefficient that closely matches aluminum and stainless steel-an important factor when mounting optics in metallic housings. In addition, different dopants can be incorporated into the UVIR glass to turn it into a broadband optical filter. Contact Mohammed Saad at [email protected].