Optical Coatings:

Enhancing Light Control and Performance
Optical coating is a specialized process involving the application of an exceptionally thin film onto the surface of optical components. This film is meticulously engineered to either enhance the transmission of light, modify the reflective properties, or manipulate the polarization of emitted light. These coatings can range from straightforward metal sheets like aluminum to intricate dielectric coatings consisting of multiple precisely designed thin layers of materials with specific thicknesses, compositions, and layer counts.

Avantier specializes in the process that involves applying thin films to optical components, enhancing light transmission, modifying reflection, or manipulating polarization. These coatings come in various types, including filter, beam splitter, high-reflective, low-reflective, and anti-reflection coatings, each serving distinct purposes. Cutting-edge technologies like IAD E-Beam, IBS, PARMS, and APS are employed in the production of these coatings. Optical coatings have evolved with technological advancements, finding applications in various industries across different spectral regions.

Dielectric Coatings Mirror
Dielectric Coatings Mirror
Fluorides coating Filter
Perforated Gold Coating Reflective Mirror

Diverse Types of Optical Coatings

Optical coatings serve various critical purposes, each offering distinct advantages. Let’s explore some of the most prevalent types:

Filter Coatings

 

  • These coatings can either enhance or diminish the appearance of images by applying one or more thin layers to a substrate.

 

  • They can reflect specific wavelengths during image transmission, tailored for different spectral regions.

Beam Splitter Coatings

  • Beam splitter coatings divide a single light beam into two separate beams, often with a predetermined transmission-to-reflectance ratio.

 

  • Depending on the application, they can manage multiple beam paths, recombine them, and control polarization.

High-Reflective Coating

  • Highly reflective optical coatings are essential in various optics applications, as they significantly improve light transmission and reflectivity.

 

  • These coatings utilize internal reflection to enhance performance and are found in automotive headlights, cell phone cameras, and other high-performance devices.
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Low-Reflective Coating

  • Ideal for applications that require maximum light throughput and minimal reflection, low-reflective optical coatings are commonly used in medical imaging, high-end camera lenses, and laser systems.

 

  • They maintain low reflectivity even at extreme angles and under challenging environmental conditions.

Anti-reflection Coating

  • Ultra-thin films of anti-reflection coatings are applied to eyeglasses and optical components to reduce reflections and glare, resulting in lighter and more comfortable eyewear with improved clarity.

 

  • They are widely used in eyeglasses, cell phones, cameras, and night vision devices.

Cutting-Edge Coating Technologies
A variety of coating technologies are employed, each offering unique benefits and suitability for specific applications. Here are some widely used optical coating technologies:

  • Ion-Assisted Electron-Beam (IAD E-Beam) Evaporative Deposition: In this technique, source materials are bombarded and vaporized in a vacuum chamber using an electron gun. It provides flexible coating design, employing a wide range of materials and large coating chamber sizes. While cost-effective and versatile, it may trade off some performance compared to other methods, especially across different spectral regions.
  • Ion Beam Sputtering (IBS): IBS yields high-quality, stable optical coatings known for their repeatability. Precise control over factors like oxidation level, layer development rate, and energy input enables the production of durable coatings. However, it comes with a higher relative cost and slower growth rates compared to some other methods, but it is excellent for producing coatings that function well in specific spectral regions.
  • Plasma-Assisted Reactive Magnetron Sputtering (PARMS): PARMS employs a glow discharge plasma to accelerate positive ions onto a target, resulting in tough and dense coatings. It offers a balance between optical performance and volume throughput and is suitable for fluorescent optical filters.
  • Advanced Plasma Sputtering (APS): APS builds upon the principles of IAD E-Beam but incorporates more advanced automation in the process. It delivers smooth, dense, and consistent coatings and serves as an intermediate solution between IBS and IAD E-Beam evaporative deposition.

In conclusion, the field of optical coatings has witnessed remarkable growth driven by technological advancements and increasing demand across various industries, including electronics and semiconductors. Optical coatings, from eyeglasses to camera lenses, represent a versatile technology with a wide range of applications and benefits that should not be underestimated.

Silicon Dioxide and Titanium Dioxide coating Lenses
Perforated Gold Coating Reflective Mirror
General Specifications

Material

Specifications

Copper

Substrate: Fused Silica, H-K9L, etc.
Surface Quality: 40-20
Chamfer: 0.5mm, 45°
Coating Material: Ag, Al, Cr, etc.
Clear Aperture: > 90% of diameter

Silver

Substrate: Fused silica, BK7
Surface Figure: < λ/10 @ 632.8nm
Surface Quality: 40-20
Chamfer: 0.5mm, 45°
Coating Material: Silver
Clear Aperture: > Central 85% of diameter

Aluminium

Substrate: Fused silica, BK7
Surface Figure: < λ/10 @ 632.8nm
Surface Quality: 40-20
Chamfer: 0.5mm, 45°
Coating Material: Aluminum
Clear Aperture: > Central 85% of diameter

 

Germanium

Substrate: Germanium, ZnSe, etc.
Surface Quality: 40-20
Chamfer: 0.5mm, 45°
Coating Material: ZnS, YbF3, Ge, etc.
Clear Aperture: > 90% of diameter

MgF2

Substrate: Fused Silica, H-K9L, etc.
Surface Quality: 40-20
Chamfer: 0.5mm, 45°
Coating Material: Al2O3, SiO3, HfO2, Ta@O5, etc.
Clear Aperture: > 90% of diameter

 

Gold

Substrate: Fused silica, BK7
Surface Figure: < λ/10 @ 632.8nm
Surface Quality: 40-20
Chamfer: 0.5mm, 45°
Coating Material: Gold
Clear Aperture: > Central 85% of diameter

Chromium

Substrate: Fused silica, BK7
Surface Figure: < λ/10 @ 632.8nm
Surface Quality: 40-20
Chamfer: 0.5mm, 45°
Coating Material: Chromium
Clear Aperture: > Central 85% of diameter

Silicon Dioxide (SiO2)

Surface Figure: PV<λ/4
Surface Quality: 60-40
Chamfer: 0.2mm×45°
Clear Aperture: >90% of the diameter

Titanium Dioxide (TiO2)

Surface Figure: PV<λ/4
Surface Quality: 60-40
Chamfer: 0.2mm×45°
Clear Aperture: >90% of the diameter

Fluorides

Surface Figure: PV<λ/4
Surface Quality: 60-40
Chamfer: 0.2mm×45°
Clear Aperture: >90% of the diameter

Dielectric Coatings

Surface Figure: PV<λ/4
Surface Quality: 60-40
Chamfer: 0.2mm×45°
Clear Aperture: >90% of the diameter

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