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ND Filters: Unmounted, AR Coated for 350 - 700 nm
NE505B-A Mounted in LMR05
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One of Our Electron Beam Deposition Chambers that is Used to Coat Neutral Density Filters
Thorlabs is pleased to offer its most popular unmounted absorptive neutral density filters with a broadband antireflection coating for the 350 - 700 nm range deposited on both surfaces. These filters are also available in mounted versions or with a broadband AR coating for the 650 - 1050 nm range. Please see the Selection Guide to the right for more information.
The high-performance, multilayer broadband A coating deposited on each filter is designed to minimize surface reflections within the 350 - 700 nm range, thereby reducing the amount of stray light present. These coatings provide an average reflectance that is less than 0.5% per surface over the specified wavelength range when light is normally incident on the filter surface. Typical transmission data is shown by clicking on the blue info icons () in the tables below.
Unlike metallic neutral density filters, each absorptive ND filter is fabricated from one member of a family of Schott glasses (see the Specs tab for more information). Each Schott glass has a spectrally flat absorption coefficient. By varying the type of glass used and the thickness of that glass, we are able to produce our entire line of absorptive ND filters from just four types of Schott glass. See below for detailed information about the average transmission obtained with each of our AR-coated absorptive neutral density filters.
Optical Density and Transmission
where T is a value between 0 and 1. Choosing an ND filter with a higher optical density will translate to lower transmission and greater absorption of the incident light. For higher transmission and less absorption, a lower optical density would be appropriate. As an example, if a filter with an OD of 2 results in a transmission value of 0.01, this means the filter attenuates the beam to 1% of the incident power. Please note that the transmission data for our neutral density filters is provided in percent (%).
Please note that these products are not designed for use as laser safety equipment. For lab safety, Thorlabs offers an extensive line of safety and blackout products, including beam blocks, that significantly reduce exposure to stray light.
The shaded regions in the graphs below denote the wavelength range for which the AR coating performance is specified. Click here to download optical density and transmission data. For the transmission and optical density of a particular filter, please click in the row corresponding to the filter in the tables below.