NE40A-A Dia. 25 mm AR-Coated Absorptive Neutral Density Filter; SM1-Threaded Mount; 350-700nm; OD 4.0 AR 350-700nm

The NE40A-A is a Neutral Density Filter, specifically designed for use in optical systems where light intensity needs to be reduced without altering the color composition of the light. This filter, sourced from Thorlabs, boasts a diameter of 25 mm and a thickness of 2.8 mm, making it a compact yet effective solution for various optical applications.

The NE40A-A filter features an Absorptive Neutral Density design, which means it reduces light intensity by absorbing a specific amount of light across the entire spectrum. This filter has an Optical Density (OD) of 4.0, which translates to a transmission of approximately 0.01% over the wavelength range of 350-700 nm. This wide spectral range makes it suitable for use with a broad spectrum of light sources.

The filter's front and back surfaces are coated with an Anti-Reflective (AR) coating, designed for the 350-700 nm range. This coating reduces unwanted reflections, improving the overall transmission and quality of the light passing through the filter. The AR coating also helps to minimize surface damage and contamination, contributing to the longevity of the filter.

The NE40A-A filter is mounted in an SM1-threaded mount, allowing for easy integration into optical systems that use SM1-compatible components. This mount also provides a secure and stable platform for the filter, reducing the risk of damage during handling and use.