Suppress stray light at the surface level with ultra-thin, vacuum deposited black coatings applied directly to your optical components.

Acktar provides fully inorganic, vacuum deposited black coatings applied directly to customer parts or supplied as coated foils and films. Coatings are typically <5 µm thick, selectively masked, and qualified to absorb unwanted light across relevant wavelengths from UV through VIS, NIR, MWIR, and into FIR reducing reflections, scattering, and ghosting before they propagate through the system.

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What Problem Does This Solve?

Stray light is any light that reaches a detector or sensitive surface outside the intended optical path. It originates from surface reflections, micro-scattering, diffraction effects, and incomplete absorption inside optical assemblies. Even very low residual reflectance can measurably degrade system performance.

In real optical systems, stray light leads to:

Loss of image contrast and dynamic range
Reduced signal-to-noise ratio
Ghost images and flare
Measurement uncertainty in metrology and spectroscopy
Unwanted thermal loading of detectors and nearby structures

The impact becomes more significant in systems involving:

Broadband spectral operation (UV–IR)
Grazing-incidence geometries and compact optical layouts
High-sensitivity detectors and low-signal measurements
Vacuum, cryogenic, or space environments

Stray-light mitigation is typically addressed through a combination of optical design, mechanical baffling, surface treatments, and, in some cases, electronic signal correction.

Paints, anodization, and polymer-based coatings can reduce reflections and are widely used in many applications. However, depending on the environment and wavelength range, they may exhibit:

Higher residual reflectance
Wavelength-dependent optical behavior
Thickness buildup affecting fine geometries
Surface instability under vacuum or thermal cycling

Mechanical baffles can block direct optical paths but do not eliminate surface reflections. Electronic correction methods can reduce visible artifacts after detection, but they do not prevent stray light from entering the optical path. For high-performance optical systems, controlling stray light at the surface level is often required in addition to mechanical and electronic strategies.

Acktar’s Approach to Stray Light Suppression

Acktar reduces stray light by qualifying absorption at the surface level using proprietary vacuum deposition processes. Fully inorganic coatings are deposited with controlled nano- and micro-scale morphology designed to trap incident light.

Key characteristics:

Extremely low total hemispherical and specular reflectance
Diffusive optical behavior that reduces ghosting
Stable absorption across wide spectral bands
Consistent performance over a broad range of angles of incidence

Because the coatings are typically <5 µm thick, they preserve sharp edges, apertures, pinholes, and fine geometries without dimensional buildup. All coatings are fully inorganic and qualified for low outgassing and long-term stability in demanding environments, including thermal vacuum, cryogenic operation, and space exposure.

In many systems, optimal performance is achieved by combining:

Surface absorption (vacuum-deposited coatings)
Mechanical baffling
Optical layout optimization
Electronic signal processing

Acktar’s contribution operates at the physical surface level—reducing unwanted optical energy before it propagates through the system.

Implementation Approaches

Acktar supports two complementary implementation paths:

Direct Coating on Customer Components
Customer furnished parts are coated at Acktar’s facilities with selective masking, ensuring only optically relevant areas are coated while functional surfaces remain untouched.
Coated Foils, Films, and Sheets
Acktar supplies pre-coated foils, films, and sheets that can be integrated into optical assemblies, applied to housings, or used for internal baffling where direct coating is not practical.

Recommended Coatings – Direct Coating on Parts

Coating Family	Typical Spectral Range	Key Optical Behavior	Typical Applications	Environmental Capability
Magic Black™	EUV – UV – VIS	Extreme absorption, ultra-low reflectance	EUV optics, UV instruments	Vacuum, cryogenic, space-qualified
Vacuum Black™	EUV – NIR	Ultra-low specular and hemispherical reflectance	Optical baffles, metrology tools	Vacuum, thermal cycling
Fractal Black™	VIS – IR (to FIR)	Diffusive ultra-black absorption	Imaging systems, spectrometers	Cryogenic to high temperature
Core Black™	EUV – NIR	Ultra-flat, particle-free, diffusive	Wafer chucks, precision mounts	Vacuum, ESD-safe, ultra-clean

Recommended Coatings – Foils, Films, and Sheets

Product	Form Factor	Spectral Range	Key Optical Behavior	Typical Applications
Hexa-Black™	Absorbing sheets / panels	UV – MWIR	Lowest reflectance at grazing angles (40°–88° AOI)	Grazing-angle baffles, beam tunnels
Metal Velvet™	Coated aluminum foils	UV – IR	Highly diffusive absorption	Light traps, internal housings
Fractal Black™ on Polyimide	Flexible films	UV – MWIR	Diffusive absorption, flexible	Internal baffling, space payloads
Fractal Black™ on Copper	Flexible copper foils	VIS – IR	Absorption + high thermal conductivity	Opto-thermal assemblies

Technical Performance

Spectral coverage: EUV/UV through VIS, NIR, MWIR, and FIR (coating-dependent)
Total hemispherical reflectance: typically <1.3%, reaching <1% at selected wavelengths
Specular reflectance: near-zero
Emissivity (3–30 µm): typically >0.85 (product dependent)
Angular performance: stable absorption at normal and grazing incidence (product dependent)
Coating thickness: typically <5 µm
Outgassing: qualified for vacuum and space applications (coating/product dependent)
Environmental compatibility: vacuum, thermal vacuum, cryogenic operation, atomic oxygen exposure (product dependent)

Performance is validated through qualification testing including thermal cycling, thermal vacuum cycling, cryogenic exposure, adhesion testing, and reflectance stability after environmental stress.

Typical Applications

Internal optical baffles and light traps
Precision apertures, pinholes, diaphragms, and stops
Imaging systems, cameras, and machine-vision assemblies
Telescopes, spectrometers, and scientific instruments
Laser beam dumps and absorbers
Semiconductor inspection and metrology tools
Spaceborne optical payloads and sensors

Integration & Compatibility

Substrates: aluminum, copper, stainless steel, titanium, tungsten, magnesium, molybdenum, nickel, Invar, Kovar, ceramics, glass, polymers, polyimide
Formats: direct coating on parts, foils, films, sheets, rolls, die-cuts, patterned components
Geometries: complex 3D parts, fine apertures, sharp edges, thin structures
Manufacturing routes: customer-furnished parts, coating of patterned sheets, customer patterning of coated materials, or full turnkey manufacturing
Cleanliness: cleanroom-compatible handling and packaging
Outgassing / UHV: fully inorganic coatings qualified for vacuum use; low-outgassing performance available for space, thermal-vacuum, and UHV environments (coating/product dependent)

Mission Proven Results

Acktar coatings are deployed in operational systems across space, semiconductor, metrology, laser, and scientific instrumentation markets, delivering measurable improvements in contrast, signal-to-noise ratio, and long term optical stability.