NDW20B Dia. 25 mm Reflective ND Filter; Optical Density 2.0

The NDW20B is a circular Neutral Density Filter with a diameter of 25 mm and a thickness of 1 mm, manufactured by Thorlabs. This filter is designed to reduce the intensity of incident light without altering its color composition, making it an essential tool in various optical applications.

The filter's Neutral Density (ND) value is 2.0, which signifies a 100x reduction in light intensity. This is achieved through a specialized coating, denoted as 'tho ndw20b' on both the front and back surfaces. This coating is uniformly applied to ensure consistent light reduction across the entire spectral range.

The NDW20B filter is made from N-BK7 Schott glass, a high-quality material known for its excellent optical properties. This glass is used in the production of precision optical components due to its low dispersion and high homogeneity.

The filter's geometry is defined by its thin lens shape, which contributes to its minimal thickness and lightweight design. This makes it an ideal choice for applications where space and weight are critical factors.

The NDW20B filter is currently in stock and available for purchase through the Thorlabs website. For more information, users can refer to the provided catalog number and weblink.