FND-25C02-1 25 mm Dia. Unmounted N-BK7 Visible Reflective Neutral Density Filter; t=2mm 400-700nm

This is the FND-25C02-1, a 25 mm diameter unmounted Neutral Density Filter from OptoSigma. The filter is designed for use in the visible spectrum, specifically between 400-700nm, making it suitable for a wide range of optical applications.

The filter is made from N-BK7 Schott, a high-quality borosilicate glass known for its excellent optical properties. This material ensures high transmittance and low absorption across the visible spectrum, making it an ideal choice for neutral density filters.

The filter features a thickness of 2mm, providing sufficient mechanical strength while maintaining minimal optical path differences. This thickness also aids in reducing unwanted reflections and scattering, contributing to improved image quality.

The filter is coated with OptoSigma's FND-1 coating on both the front and back surfaces. This coating is designed to provide high reflectivity in the visible spectrum, making it suitable for reflective neutral density applications. The coating also offers excellent environmental stability, ensuring the filter's performance over time.

The filter's circular shape and thin lens design allow for easy integration into various optical systems. The unmounted design provides flexibility in choosing the right mount for your specific application.