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ND Filters: Mounted, AR Coated for 350 - 700 nm
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ND Filters Being Ground at Our Optics Manufacturing Facility
Thorlabs is pleased to offer its most popular mounted absorptive neutral density filters with a broadband antireflection coating for the 350 - 700 nm range deposited on both surfaces. These filters are mounted in engraved SM1L03 Ø1" lens tubes, which are compatible with a wide range of rigid optomechanical parts such as our cage systems and lens tubes. These filters are also available in unmounted 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 reflectivity that is less than 0.5% over the specified wavelength range when light is normally incident on the filter surface. Typical filter transmission data is available by clicking on the 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 (OD) indicates the attenuation factor provided by an optical filter, i.e. how much it reduces the optical power of an incident beam. OD is related to the transmission, T, by the equation
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 (%).
For lab safety, Thorlabs offers an extensive line of safety and blackout products that significantly reduces exposure to stray light.
The shaded regions in the graphs below denote the recommended wavelength range for these filters. For the transmission and optical density of a particular filter, as well as raw data files, please click in the row corresponding to the filter in the tables below.