NE2R01B Dia. 2 in Absorptive ND Filter; Optical Density 0.1

The NE2R01B is a Neutral Density (ND) Filter, designed and manufactured by Thorlabs. This particular model boasts a circular shape with a diameter of 50.8 millimeters and a thickness of 0.6 millimeters, making it compatible with a wide range of optical systems.

The filter's primary function is to reduce the intensity of incident light without altering its color composition. This is achieved through the use of a specialized coating, referred to as 'tho ne01a', which is applied to both the front and back surfaces of the filter. This coating is responsible for the filter's optical density of 0.1, meaning it reduces the light intensity by a factor of 1.26 (approximately).

The NE2R01B is crafted from N-BK7 Schott, a high-quality optical glass known for its excellent transmittance and low auto-fluorescence. This material ensures the filter maintains high optical performance across a broad spectrum, specifically at the wavelength of 633 nanometers.

In terms of design, the NE2R01B features a 'Thin Lens' shape, which is beneficial for maintaining the overall compactness and integrity of the optical system. The filter's catalog number is NE2R01B, and it is currently in stock on Thorlabs' website, as indicated by the 'weblink status'.