This is the 16-055 Neutral Density Filter from Edmund Optics, a high-quality optical component designed for precision applications. The filter boasts a 25 mm diameter and a thickness of 2.11 mm, making it a versatile choice for various setups.
The filter is made from SCHOTT NG5 glass, a material known for its excellent optical properties. This includes a high Abbe number, low auto-fluorescence, and excellent transmission in the visible spectrum. The NG5 glass also has a low refractive index, making it an ideal choice for applications where dispersion needs to be minimized.
The Neutral Density aspect of the filter is achieved through a precise absorptive coating on both the front and back surfaces. This coating, identified as EDM 16-055, provides an Optical Density (OD) of 0.5 across the wavelength range of 450-700nm. This means that the filter reduces the intensity of incident light by a factor of 10^0.5, or approximately 30%, while maintaining a neutral color balance.
The filter is designed with a Thin Lens shape, which helps to minimize optical aberrations and distortions. This makes it suitable for use in high-resolution imaging systems and other applications where optical quality is paramount.