“By bringing more color into the glass, we have been able to produce a very thin optical filter to keep radiation in the wavelength range from 600 to 1100 nm away from the eye,” explains Dr.-Ing. Ralf Biertümpfel, Application Manager Filter Glass at SCHOTT Advanced Optics. “For laser safety eyewear, VG20 offers improved wearing comfort – it is roughly one third lighter than conventional filter glass.”
VG20 is extremely transparent in the visible range of the electromagnetic spectrum: It conveys true colors with very little darkening. The cut-off wavelength l05, at which the glass has a transmittance of 50 percent, is at 565 nm and then drops steeply. From 750 to 1100 nm, the green glass is nearly impenetrable. Regardless of the angle of incidence, the solid-colored glass safely protects from laser beams.
In addition, the filter glass is highly climate-resistant: it stays moisture- and heat-proof, permanently transparent, and corrosion-free for hundreds of hours. For customer-specific applications, the filter properties can be optimized with additional coatings. VG20 is suitable for protection from red and NIR lasers in a wavelength range above 650 nm – for instance in metrology and medical technology.
Additional information: www.schott.com/advanced_optics