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Acktar Advanced Coatings

Acktar Advanced Coatings

Authors: Samuel Josephs


Acktar is a world leader in light absorbing materials and coatings, that provide solutions for stray light suppression in the UV, VIS, SWIR and MWIR wavelengths.

Available Black Foils and Direct Coated optomechanics are ideal for light trapping applications such as within lens housings, baffles, IR sensors, UV sensors, passive infrared detectors, black bodies, light detectors, UV absorbers, etc. Find our full product lineup here.

In optics and photonics applications, Acktar coatings and foils are able to selectively suppress stray light and significantly increase signal-to-noise ratio, so you get the clearest and most accurate readings and images from your sensors. Acktar coatings and foils also have a high laser damage threshold and can dissipate heat efficiently - perfect for catching a stray laser beam before it can cause damage to you or your system.

Edmund Optics® Offering

Edmund Optics® offers Acktar foils in sizes from 1” diameter stickers, up to 50m long rolls. Acktar foils come in many coating options: Metal Velvet, Lambertian Black, Maxi Black, Spectral Black, and Hexa Black. Each coating type is designed with varying reflective performance, with differing ideal spectral ranges so that there is a coating with is ideal for your application.

We also offer direct coated optomechanics products, such as optical pinholes and optical slits for spatial filtering, Hexa-Black coated C-Mount tubes for noise reduction, as well as beam dumps to safely control the beam in your laser system.

Acktar Performance Data

Different Acktar Black Coatings are better suited to specific optical applications depending on the design wavelength of the system or application.

Figure 1: Hemispherical Reflectance of Acktar Black Coatings at Specific Wavelengths

It is also important to understand the typical angle of incidence of the system and the abrasive resistance required for the application when selecting the ideal black coating for the application. Please reference the table below that compares the different types of Acktar Black Coatings.

Foil Type Metal Velvet™ Extra Diffusive Lambertian Black™Ultra Diffusive MaxiBlack™Diffusive Polyimide Spectral Black™Semi-Specular Hexa Black™Semi-Specular
Substrate Material Aluminum Stainless Steel Polyimide (Kapton) Aluminum Aluminum Honeycomb
KEY FEATURE Reflectance -1% High Absorptance at Grazing Angles Thin Polyimide Semi Specular Finish Ultra-high Absorptance at Grazing Angles
Thickness 120µm 100µm 25/50/75µm 130µm 2mm
Appearence Diffusive Highly Diffusive Diffusive Specular Diffusive 3D Structure
AOI Range 0-60° 0-80° 0-60° 0-45° 0-88°
Reflectance normal AOI <1% <1.5% <2.5% <2% <1.5%
Abrasion Resistance Light Moderate to high Moderate Moderate Moderate plus
Self adhesive back Self adhesive back standard - available without adhesive
Service Temperature
Without Adhesive: Long term (-)196°C to (+)350°C; short term up to (+)400°C (-)258°C to (+)250°C
With Standard Adhesive: Long term (-)40°C to (+)121°C; short term up to (+)177°C
With Low-Outgassing: Long term (-)50°C to (+)150°C; short term up to (+)260°C
Figure 2: Comparison of Acktar Black foils types.
Metal Velvet™ /
Spectral Black™
Commercial Flock Paper Black Anodized Foil
Materials Content Completely Inorganic Organic/Fibers Non Organic Basis + Pigments
Ultra High Vacuum Compatible Probably Incompatible - Outgassing Compatible
Laser Damage Threshold Very High Low Low
UV Tolerance Very High Low Low
Particulation Metal Velvet™ - Minimal
Spectral Black™ - None
Particulates None
Thermal Conductivity High Low Low
Electrical Conductivity Conductive Non-conductive Low
Operating Temperature, Adhesive Limited [C] -40 to 180 No Data ~150
Fluoresence None High High
Figure 3: Comparison of Light Blocking Performance of Acktar Metal Velvet and Spectral Black vs. Flock Paper and Black Anodization.
Spectrum WL [NM]
Metal Velvet™ Spectral Black™ Flock Paper Anodized Foil
R [%] R [%] R [%] R [%]
UV 190-405 1 1 Limited Use Limited Use
VIS 400-780 1 1.5 3.5 5
NIR-SWIR 800-1700 1.2 2 >25 >20
MSWIR 3000-5000 2 3 >15 17
LWIR 8000-11000 4 7 5 5
  • R[%] refer to peak reflection value in the WL range
  • Black anodized / Flock are typical data
Figure 4: Reflection Performance of Acktar Black Coatings at Specific Wavelength Bands.
Figure 5: Visual Comparison of Light Blocking Performance of Acktar Black Coatings in IR vs Conventional Black Coating.

Find our full offering of standard Acktar Foils and Direct Coated Optomechanics here. If you have a demanding application, please feel free to reach out to us for custom sizes or substrates.

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