Schott's 1mm thin band-pass filter VG20 that shows strong absorption in the near infrared (NIR) range is now available.
VG20 is extremely transparent in the visible range of the electromagnetic spectrum, with little darkening. The cut-off wavelength l05, at which the glass has a transmittance of 50 per cent, is at 565nm and then it drops steeply. From 750 to 1100nm, the green glass is nearly impenetrable. Regardless of the angle of incidence, the solid-coloured glass safely protects from laser beams.
In addition, the filter glass is highly climate-resistant; it stays moisture- and heat-proof, is permanently transparent, and corrosion-free for hundreds of hours. For customer-specific applications, the filter properties can be optimised 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.