Tech focus: optical coatings

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A look at the current market for optical coatings and some of the products and solutions available

Optical coatings incorporate various thin film layers that, together, can strengthen the properties of an optical system. These coatings are produced using a variety of materials; properties such as the number of or thickness of the layers and refractive index difference direct the performance of the coating. 

Optical coatings are often used to enhance the reflective property of an optical system, but they can also aid resistance to chemicals or abrasion. Some are used to provide UV resistance, or antistatic, anti-glare and anti-fog properties. 

Optical coatings are not a new technology. One of the earliest dates back to 1886 and was attributed to English scientist, Lord Rayleigh, who found that the kind of tarnishing that affected the optical glass of the time could potentially provide an advantage. Technical breakthroughs – combined with increased demand from end-users for efficient optical devices – are driving growth in today’s market. According to a recent study by Future Market Insights, the worldwide optical coating market is anticipated to grow at a compound annual growth rate (CAGR) of between 8 and 9 per cent between 2021 and 2031. 

The study highlighted that the increasing global demand for consumer electronic devices is likely to boost the market. It also predicted that the rapid urbanisation which is impacting consumer behaviours will improve the prospects for smart electronic gadgets and so, too, influence demand for optical coatings.

Commercial products

Vendors offering optical coatings products and solutions include AccuCoat, which provides thin-film coatings on polymer, metal and glass components. The company also offers a variety of antireflective, beamsplitter, hot and cold mirror, filter, metallic and custom coatings. 

Angstrom Engineering’s Reticle platform gives the ability to create films with high purity, density and uniformity, in a repeatable and automated fashion. This is useful for applications such as anti-reflective (AR) coatings, highly reflective (HR) coatings, coatings for laser diode bars and telecom optical filters, as well as vanadium oxide deposition. 

Applied Optics Center (AOC) designs and manufactures thin-film optical coatings for both visible and IR applications, specialising in high-layer-count coatings associated with laser protection optics. 

Alluxa is an ISO 9001:2015 certified, ITAR registered manufacturer of high-performance optical filters and thin-film coatings. At the heart is the company’s advanced Sirrus plasma deposition process. Products include the Ultra Series of optical filters and thin-film coatings as well as custom optical filters and thin-film coatings.

Avantes offers a number of solutions that are useful for the coating industry, including proprietary software designed for the needs of this market. The company’s specialist spectrometer has been deployed into multiple thin-film applications. Reflection and transmission-based thin-film measurements are typically done in the 200-1,100nm range and are suited to coatings ranging from 10 nm-50µm. 

Berliner Glas produces coatings for different kinds of applications. The spectral range extends from the VUV to the infrared range. Coatings include anti-reflective layers; highly reflective metallic and dielectric mirrors; polarising and non-polarising beam splitters; narrow band filters; edge filters; laser protection filters; layer coatings with high damage threshold and absorption layers. 

Cascade Optical manufactures custom vacuum-deposited thin-film coatings. The company offers ion-assisted deposition and low-temperature, low-stress coatings for laser crystals and fibre optics, with prototypes available to production quantities. 

Chroma Technology produces optical coatings for demanding applications including biomedical and imaging systems, fluorescence microscopy, aerospace, surveillance, machine vision, industrial inspection for items such as semiconductors, food and lumber, multispectral imaging and chemical analysis. 

Edmund Optics has expertise in producing coatings for advanced diagnostic applications, harsh environment imaging assemblies and applications throughout the ultraviolet (UV), visible (VIS) and infrared (IR) spectral regions. Available are anti-reflection (AR) and metallic mirror coatings; a wide range of custom optical coatings are made in internal coating facilities. 

Inrad Optics uses a plasma assisted deposition system to produce thin film coatings on optics as large as 60” across. This method allows the company to produce thin films, which it says have higher density, lower internal stresses and higher adhesion than conventional deposition systems. 

Iridian Spectral Technology provides optical thin film solutions and coating services to a wide variety of industrial and research sectors. The company is a global supplier for applications in telecommunications, spectroscopy (Raman, fluorescence, flow cytometry), the entertainment industry (filter wheels, glasses for 3D cinema), and optical sensing (Earth-Observation remote sensing, MWIR gas sensing).

II-VI thin-film coatings enable optics to achieve desired spectral characteristics across the electromagnetic spectrum. The company produces low-absorption coatings for low to very high-energy lasers, on a broad range of crystals and metals and on standard flat or curved surfaces as well as surfaces precision-shaped by diamond turning. 

Lambda Research Optics manufactures components for defence, commercial and medical laser applications. The company also specialises in high-power coatings for excimer, YAG, fibre, CO2 lasers and FLIR coatings. Precision polishing of CaF2 , MgF2 , BK7, fused silica, ZnSe, Ge and Si. 

Laser Components supplies optics that cover the spectral range from 193nm to 3.0µm. The company also has the facilities to coat its own substrates as well as those supplied by customers, with diameters ranging from 4 to 390mm. The department has five coaters, one of which uses sputter technology, designed for the manufacture of the next generation of lasers. 

MLD Technologies produces high-performance optical coatings and components, specialising in the design, development and manufacture of ion-beam sputtered, low optical loss, laser-damage resistant thin films for the UV-VIS-IR spectral region. Applications include lasers, laser devices, nonlinear crystals, medical instruments and other photonic devices. 

Materion provides precision dielectric and metal thin film coatings that have excellent spectral performance, environmental stability and substrate adhesion. The company’s multiple coating processes can coat a host of substrates for optical systems applications. Products include anti-reflective, cold mirror and index matched ITO coatings. 

Northrop Grumman Synoptics specialises in high laser damage threshold coatings, using the latest thin film coating technologies such as ion-beam sputtering (both conventional and Quasi-Rugate structures) and Electron-Beam coatings, optimised for high laser damage thresholds from 355-2,140nm. 

NTT Advanced Technology provides x-ray/EUV optics and coatings; multilayer and total reflection coatings as well as high-reflectivity, narrowband and broadband coatings. The company also offers optics such as filters, dichroic mirrors and beam separators for the x-ray/ EUV region.

OptoSigma supplies a wide range of optical thin film coatings. These are often provided as part of the optical component, but may also be ordered separately to apply to an uncoated element. Applications include bio-tech dichroic filters, bio-medical high laser damage threshold AR or HR coatings for laser delivery systems and space-rated optics. 

Quantum Coatings boasts a large in-house optical coating capability, allowing the company to meet requirements for optics up to 2000lbs and 1.5m in diameter. Its thin film coatings have been used in applications including: avionics, aerospace, military and medical. 

Semrock (a subsidiary of Idex) manufactures optical filters for the life science industry. All filters coated in the company's sophisticated sputtering deposition chambers are tested extensively both in-situ and postproduction to ensure performance and quality, and can be scaled easily from prototype to volume production with no change in performance.

Spectrogon’s coating service capabilities span 193-20,000nm, including anti-reflection coatings in single and multilayer, broadband AR coatings, extended BBAR coatings, laser line and dual wavelength AR coatings, UV laser coatings and high reflective coatings. The company also offers metallic high reflective coatings. 

Viavi Solutions can design and manufacture virtually any interference filter that obeys the laws of physics, through its broad technology portfolio and decades of experience. Its knowledge of materials, foundational physics of deposition processes, and impressive in-house analytical capability, enable it to offer innovative and advanced processeses in production. 

Zeiss International provides high-quality coatings, simulating and optimising the process in advance (including coating properties) to achieve an optimal result; from the thickness distribution to the coating stress to the scattered light. The standard range includes more than 250 optical coatings.

This is not an exhaustive list. If you provide optical coatings and would like your company to be included, please let us know.

 

Featured product: Avantes

There is a worldwide increasing demand for spectrometers. More and more customers purchase in large volumes, meaning that the performance of each spectrometer must be the same. Historically, Avantes’ spectrometers are assembled by hand with great precision, but the company has now automated this process, calling it ‘AvaMation’. This way of manufacturing provides unsurpassed inter-instrument reproducibility and scalability in production. 

Avantes decided to innovate this process to increase efficiency, precision, and to be ready for a future with an increasing demand for spectrometers. Its CompactLine spectrometers are the first instruments manufactured with AvaMation. AvaMation also yields lots of benefits for end-users:

  • Scalable manufacturing capabilities: customise orders, from small to very high volumes.

  • Superior inter-instrument reproducibility: quality assurance, manufacturing precision and speed.

  • Enabling data analysis: continuously improving and innovating products by collecting data from the manufacturing process. 

Curious how Avantes’ CompactLine spectrometers improve your application? Visit www.avantes.com/compactline for more information.

Featured product: Laser Components

Laser Components is entering its 26th year as a manufacturer of the highest quality optical coatings. It remains one of the only manufacturers worldwide capable of producing Gaussian mirrors, also known as variable reflecting mirrors (VRM). These special optics are characterised by a degree of reflection which slopes from the centre of the part in a Gaussian distribution. 

Gaussian mirrors are used in unstable resonators, where they help produce high-quality laser beams with low beam divergence at high pulse energies. In frequency-doubled systems they are used to achieve a greater pump efficiency. The Gaussian mirrors are extremely stable and therefore suited for the highest power levels. 

They are generally manufactured as custom parts and are characterised and measured using proprietary methods, yielding high quality and strict adherence to customer specifications. 

Further information www.lasercomponents.com/uk/product/gaussian-mirrors

Featured product: Spectrogon

Coating service capabilities from Spectrogon Spectrogon’s Coating Service capabilities (400-20,000nm) for OEM customers include:

  • Anti-reflection (AR) coatings: Single and multilayer coatings; Broadband AR coatings; Extended BBAR coatings; Laser line AR coatings and dual wavelength AR coatings.

  • High reflective coatings: Metallic high reflective coatings; Dielectric laser line HR coatings; and dielectric HR coatings.

  • Beam splitter coatings: 400-20,000nm 

Send us your requests at: www.spectrogon.com/contact-us/requests/coatings

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