The ND03A is a Neutral Density (ND) Reflective Filter, manufactured by Thorlabs, with a diameter of 25 mm and a thickness of 1 mm. This filter is designed for use with optical systems that require neutral density filtration, and it features an SM1-threaded mount for easy integration into existing setups.
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, denoted as 'tho nd03' on both the front and back surfaces. This coating has an optical density of 0.3, which corresponds to a reduction in transmittance of approximately 20%.
The ND03A filter is made from N-BK7 Schott glass, a material known for its excellent optical properties and high damage threshold. The filter's shape is described as 'Thin Lens', indicating that it may have some degree of optical power, although this is not explicitly stated in the provided data.
The filter's web links are valid and indicate that it is currently in stock, making it readily available for immediate use in optical systems.