The FGL850M is a color glass filter developed by Thorlabs, boasting a catalog number of FGL850M and a longpass cut-on wavelength of 850nm. This filter is designed for use in optical systems that require longpass filtration, making it suitable for various applications.
The filter is circular in shape, with a diameter of 25 mm and a thickness of 2 mm, making it compatible with SM1-mounted systems. It is made from high-quality n-bk7 Schott glass, ensuring durability and reliability in its performance. The FGL850M features thin lens geometry, which is beneficial for maintaining the overall optical path length in your system.
The FGL850M's coating is a crucial aspect of its design. Both the front and back surfaces are coated with the THo FGL850 coating, which contributes to its longpass filtration capabilities. This coating ensures efficient light transmission while effectively blocking unwanted wavelengths.
The filter's physical data further highlights its capabilities. With a cut-on wavelength of 850nm, it allows transmission of longer wavelengths while blocking shorter ones. The cut-off wavelength is 0nm, indicating that it blocks all wavelengths shorter than 850nm.