The NE13A is a Neutral Density Filter with a diameter of 25 mm, manufactured by Thorlabs. This filter is designed to reduce the intensity of incident light without altering its color composition, making it an ideal tool for various optical applications. The NE13A features an optical density of 1.3, which corresponds to a reduction of approximately 40% in light intensity.
This filter is made from N-BK7 Schott, a high-quality optical glass known for its excellent transmittance and low auto-fluorescence. The filter's geometry includes a thickness of 2.5 mm, providing durability and stability. The NE13A is mounted with an SM1-threaded mount, ensuring a secure and easy-to-use installation in your optical setup.
The NE13A's coating is another notable feature. Both the front and back surfaces are coated with Thorlabs' proprietary NE13A coating, designed to enhance the filter's performance and durability. The coating also gives the filter a 'Thin Lens' shape, which can be beneficial in certain optical configurations.