How Substrate Material Affects Optical Coating Performance
Two optical windows may use the same nominal anti-reflection coating design, yet deliver different optical results. One may achieve the expected reflectance, while the other…
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Optical Materials & Infrared
GIAI’s latest optical information display area contains a variety of news and information on popular science explanations, working principles, usage tips, etc. of various optical filters, prisms, lenses and components. There is always one that interests you.
How Anti-Reflection Coating Is Selected for a Lens
An anti-reflection (AR) coating for a lens is not picked from a catalog name. It is selected by working backward from the optical system: what…
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What Is Angle of Incidence (AOI) in Optics?
A narrowband optical filter may meet its wavelength specifications during laboratory testing but behave differently after installation in an optical system. One possible reason is…
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How Coating Design Balances Transmission and Blocking
An optical filter may deliver excellent peak transmission at its specified wavelength yet still perform poorly in an imaging or sensing system. The problem is…
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How Coating Stress Affects Optical Flatness: Causes & Fixes
A substrate can leave polishing at λ/10 and come out of the coating chamber measuring a full wave of error. The polishing did not change.…
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ZnSe vs Germanium for Infrared Lenses
Germanium suits 8–12 µm imaging lenses: an index of 4.0 and very low LWIR dispersion keep element count and curvature low. ZnSe suits high-power CO2…
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How to Choose a Silicon Lens for Infrared Systems
Choosing a silicon lens starts with the operating wavelength, not the lens diameter or catalog shape. Confirm that silicon is suitable for the complete spectral…
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Optical Thickness vs Physical Thickness in Thin Films
Physical thickness is the actual geometric thickness of a thin-film layer, while optical thickness describes how that layer affects the phase of light. At normal…
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What Determines the Laser Damage Threshold of a Coating?
The laser damage threshold of an optical coating, usually referred to as the laser-induced damage threshold or LIDT, is not determined by the coating material…
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Clear Aperture vs Optic Diameter
Optic diameter is the physical outside diameter of a circular optical component. Clear aperture is the region of that optic over which specified optical performance…
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What Makes Optical Coating Expensive?
Two optical components can look almost identical, use the same substrate material, and have similar dimensions—yet their coating costs may be very different. The reason…
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What Is an F-Theta Scan Lens and How Does It Work?
The topic is suitable as a foundational definition page. GIAI already has more specific content covering 1064 nm F-theta lenses, field-size calculation, standard vs. telecentric…
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