The 11-990 is a 25 mm diameter First Surface UV Bandpass Filter with a thickness of 1.5 mm, specifically designed for a central wavelength of 253.7 nm. This filter is sourced from the reputable vendor, Edmund Optics, and is available for purchase on their website.
The filter is a Bandpass type, which means it allows light to pass through a specific range of wavelengths while blocking other wavelengths. In this case, the 11-990 filter is designed to pass light between 248.7 nm and 258.7 nm, making it ideal for applications that require the use of ultraviolet light.
The filter is made from UVFS Mal-1965 material, a type of glass specifically designed for UV applications. The front and back of the filter are coated with EDm 11-990, a coating that enhances the filter's performance and durability.
The filter's geometry is that of a Thin Lens, which means it has a very thin profile relative to its diameter. This makes it suitable for use in applications where space is limited.