Double-Sided Anti-Reflection Coating for Optical Glass

Double-side AR coating is applied to both optical surfaces to reduce reflection and increase transmission through the substrate. It is suitable for optical glass, fused silica, quartz, sapphire, CaF₂, silicon, germanium, ZnSe and glass-ceramic substrates.

Available coating designs can include single-wavelength AR, broadband AR, dual-band AR and wavelength-specific custom coatings. Coating parameters can be configured by wavelength range, angle of incidence, substrate material and reflectance target.

Typical applications include optical windows, laser optics, camera lenses, microscope optics, sensor covers, imaging systems, spectroscopy components and semiconductor optical assemblies. Double-side AR coating can be supplied for custom dimensions, shapes and optical specifications.

What Is Broadband AR Coating?

Broadband anti-reflection (BBAR) coating is a multi-layer thin-film design optimized to minimize surface reflectance simultaneously across a wide wavelength range — typically spanning 100 nm or more — rather than at a single design wavelength. Unlike a V-coat, which achieves extremely low reflectance (< 0.2%) at one specific wavelength but rises sharply on either side, a broadband design uses a more complex layer stack (typically 5–9 layers) with graded refractive index transitions to distribute the destructive interference condition across the full target band. The trade-off is a slightly higher minimum reflectance compared to a V-coat, but with dramatically better uniformity across the spectrum. This makes BBAR coatings the standard choice for white-light imaging systems, broadband laser platforms, multi-wavelength instruments, and any optical system where performance must be maintained across a range of wavelengths rather than optimized for a single line. Deposition is performed by ion-beam sputtering (IBS) or magnetron sputtering with real-time optical monitoring, ensuring layer thickness accuracy to ±0.5 nm and coating uniformity within ±0.5% reflectance across a 200 mm substrate.

Coating Performance Specifications

Design Band	Wavelength Range	Ravg	Rmax
VIS BBAR	400 – 700 nm	< 0.5%	< 1.0%
NIR BBAR	700 – 1100 nm	< 0.5%	< 1.0%
VIS-NIR BBAR	400 – 1100 nm	< 1.0%	< 1.5%
UV-VIS BBAR	350 – 700 nm	< 0.8%	< 1.2%
UV-VIS-NIR BBAR	350 – 1100 nm	< 1.5%	< 2.0%
Extended NIR BBAR	600 – 1600 nm	< 1.0%	< 1.5%
Custom BBAR	Customer-specified	Design-dependent	Design-dependent

Layer count: 5–9 layers · Thickness accuracy: ±0.5 nm · Uniformity: ±0.5% R across 200 mm · AOI: 0°–30° standard

Compatible Substrates

	Substrate	Typical Grade
1	Fused Silica	Corning 7980 / Tosoh ES-2000
2	Quartz Glass	SCHOTT Lithosil Q / Heraeus Suprasil 1
3	Borosilicate Glass	PYREX 7740 / BOROFLOAT 33
4	Optical Glass	BK7 / N-BK7 / N-SF11 / N-LAK series
5	Sapphire	C-plane / A-plane
6	CaF₂	UV-grade / IR-grade
7	MgF₂	UV-grade
8	ZnSe	CVD-grade
9	Germanium	Single crystal / Polycrystalline
10	Silicon	Float Zone / Czochralski
11	Glass-Ceramic	ZERODUR / PYROCERAM 9606

Layer Structure & Design

Design	Layer Materials	Layer Count	Deposition Method
VIS BBAR	TiO₂ / SiO₂	4 – 5	IBS / Magnetron
NIR BBAR	TiO₂ / SiO₂	4 – 5	IBS / Magnetron
VIS-NIR BBAR	Ta₂O₅ / SiO₂	6 – 7	IBS
UV-VIS BBAR	HfO₂ / SiO₂ / MgF₂	5 – 6	IBS (ion-assisted)
UV-VIS-NIR BBAR	Nb₂O₅ / SiO₂ / MgF₂	7 – 9	IBS
Extended NIR BBAR	Ta₂O₅ / SiO₂	5 – 7	IBS / Magnetron

All designs optimized via needle synthesis and transfer matrix method · Custom AOI and substrate available

Typical Applications

Scientific Imaging: VIS-NIR BBAR on microscope objectives and spectrometer optics for broadband detection
Machine Vision: VIS BBAR on industrial camera lenses for consistent throughput across white-light illumination
Multi-Wavelength Laser Systems: VIS-NIR BBAR on shared-aperture optics handling 532 nm, 1064 nm, and 1550 nm simultaneously
Astronomy & Telescope Optics: UV-VIS-NIR BBAR on corrector plates and field flatteners for broadband sky surveys
Defense & Surveillance: Dual-band VIS/NIR BBAR on sensor windows for day/night imaging systems
Photovoltaics: UV-VIS-NIR BBAR on solar concentrator lenses and cover glass for maximum light harvesting

Environmental & Durability Standards

Test	Condition	Standard	Result
Adhesion	Tape peel test	MIL-C-48497A	No delamination
Abrasion	50 strokes eraser	MIL-C-48497A	No coating removal
Humidity	95% RH · 49°C · 24h	MIL-STD-810	No blistering
Temperature Cycling	–65°C to +125°C · 10 cycles	MIL-STD-810	No cracking / peeling
Salt Fog	5% NaCl · 35°C · 24h	MIL-STD-810G	No corrosion
Laser Damage	1064 nm · 10 ns pulse	ISO 11254	LDT > 5 J/cm²
Solubility	Distilled water · 24h immersion	ISO 9211-3	No dissolution