FND-20C02-70 20 mm Dia. Unmounted N-BK7 Visible Reflective Neutral Density Filter; t=2mm 400-700nm

The FND-20C02-70 is a high-quality Neutral Density Filter, unmounted and with a 20 mm diameter. This filter is designed for use in the visible spectrum, specifically between 400 and 700 nanometers. The filter is made from N-BK7 Schott, a well-regarded optical glass known for its excellent transmittance and low auto-fluorescence.

The filter features a thickness of 2mm, which is ideal for applications requiring a balance between durability and minimal optical path distortion. The front and back surfaces of the filter are coated with Opt FND-70, a reflective neutral density coating that provides a uniform attenuation across the visible spectrum. This coating is designed to maintain the color balance of the incident light, making it suitable for applications such as photography, beam shaping, and laser attenuation.

The filter's shape is that of a thin lens, which minimizes edge effects and ensures a uniform transmission across the entire diameter. This filter is sourced from OptoSigma, a reputable vendor known for their high-quality optical components. The filter is currently in stock and available for immediate shipping, as indicated by its weblink status.