Our supplier is a leader in flat response neutral density filters in the UV to near infrared (250nm-2000nm) and far infrared (2000-14000nm). These coatings are hard and pinhole-free, with any optical density possible at any size. The coatings exhibit industry-leading spectral neutrality over a broad wavelength range, with optical densities up to 4.0.
Metallic-coated neutral density (ND) filters obtain their optical density from a metal alloy coating on a substrate determined by the wavelength region of interest. Unlike the all-dielectric or absorption type, the metallic type ND filter employs a combination of absorption and reflection to reduce the intensity of light. While able to withstand more incident energy than the absorptive type, metallic ND filters are suitable only for low-power applications. (Note: If used in series, these filters should be tilted to avoid multiple reflections and any reduction of density).
With their ability to minimize back-reflections and scattered light, absorptive neutral density (ND) filters are ideal for calibration. In contrast to the metallic type, absorption-type filters achieve their optical density by absorbing light within the substrate. For this reason, thickness is a key determinant of opacity. Because of their absorbing quality, these filters are suitable for low-power applications only.
Absorption and metallic-coated neutral density (ND) filters. The metallic coated type ND filters employs a combination of absorption and reflection to reduce the intensity of lights. The absorptive filters feature the ability to minimize back-reflections and scattered light. They are therefore ideal for calibration.