FND-15C02-92 15 mm Dia. Unmounted N-BK7 Visible Reflective Neutral Density Filter; t=2mm 400-700nm

This is the FND-15C02-92, a 15 mm diameter unmounted Neutral Density Filter, manufactured by OptoSigma. The filter is made of N-BK7, a type of high-quality borosilicate glass, specifically from the Schott glass catalog.

The filter's primary function is to reduce the intensity of light, making it ideal for applications where high light levels could potentially damage the equipment or distort the results. The N-BK7 material ensures high optical quality, low auto-fluorescence, and excellent transmission in the visible spectrum.

The filter features a reflective coating, Opt FND-92, on both the front and back surfaces. This coating is designed for the visible spectrum, specifically for wavelengths between 400 and 700 nanometers. The coating's neutral density characteristic ensures equal attenuation of all wavelengths, resulting in a consistent color balance.

The filter has a thickness of 2mm, which is considered 'thin' in optical terms. This thinness, combined with the circular shape, gives it a 'Thin Lens' geometry. This geometry is beneficial in applications where space is limited or where the filter needs to be mounted in front of a lens.

The filter is currently in stock and available for purchase. For more information, you can visit the product page at https://www.optosigma.com/us_en/optics/filters/neutral-density-filters/reflective-neutral-density-filter-unmounted-visible-15mm-diameter-92i1-4-FND-15C02-92.html.