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

The FND-20C02-20 is a high-quality Neutral Density Filter, unmounted and with a 20 mm diameter. This filter is designed for use in the visible light 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's geometry is optimized for versatility and ease of use. It has a thickness of 2mm, which provides sufficient structural integrity while minimizing optical distortion. The circular shape is a standard in optical systems due to its symmetry and ease of alignment.

The filter's coating is another notable feature. Both the front and back surfaces are coated with Opt FND-20, a reflective neutral density coating. This coating reduces the amount of light that passes through the filter without altering the color balance, making it ideal for applications where light intensity needs to be controlled without affecting the spectral composition.

The filter's shape is thin lens, which is beneficial in applications where space is a constraint or where minimal optical distortion is required. This filter is currently in stock and available for immediate purchase from OptoSigma, a reputable vendor known for their high-quality optical components.