Optical metrology is a branch of metrology, the science of measurement, that uses optical principles and technologies to measure physical quantities with high precision. There are numerous techniques and instruments that use light from optical sources to make accurate measurements of various parameters such as distance, shape, surface roughness, and more.
Common techniques include interferometry, which involves the interference of light waves to measure variations in distance or surface shape. Laser-based distance measurement systems are used for distance measurements in applications such as manufacturing, while holographic techniques are used for precision measurements and visualisation of 3D objects. Optical profilometry measures surface profiles and roughness using optical instruments. It is commonly used in industries such as microelectronics and optics manufacturing.
Optical metrology has applications in various industries, including manufacturing, aerospace, automotive, medicine, and research. The non-contact nature and high precision of optical metrology methods make them valuable tools for ensuring quality control and conducting detailed measurements in diverse fields.
Optical metrology equipment relies on a variety of optical components, the choice of which depends on the specific technique and application. Common optical components used in optical metrology include: lenses, mirrors, polarisers and analysers, prisms, optical filters, optical detectors, such as photodiodes or charge-coupled devices (CCDs), collimators and diffraction gratings.
Optical metrology products on the market now
Vendors of optical metrology instruments and related optical equipment include Asphericon, which specialises in aspheric optics and offers a range of precision optical components used in metrology and imaging systems. Its product portfolio for metrology includes spheres, aspheres and freeform optics. It also provides optical mirrors, optical systems for homogeneous beam shaping and optical coatings from UV to IR.
Bruker is a manufacturer of high-performance scientific instruments and analytical and diagnostic solutions designed to enable scientists to explore materials at molecular, cellular and microscopic levels. The company provides optical profiling systems and interferometers for surface analysis and nanoscale metrology.
4D Technology designs and manufactures dynamic laser interferometers and optical profilers, and surface defect gauges. Applications include precision machined surfaces, optics, astronomy, aerospace, space-based telescopes, flexible electronics, automotive, and in-line production measurement.
Daheng New Epoch Technology is a technical company that specialises in optics. It provides optical and imaging products, including lenses, filters, and cameras for metrology applications.
Edmund Optics is a supplier of optics, imaging, and photonics products. The company offers a wide range of optical components, including lenses, mirrors, filters, and beam splitters for various metrology applications.
Hamamatsu offers a variety of photonic product solutions, which were designed to achieve the performance levels required for optical measurement applications. The company’s optical products are used in applications including gas analysis and range finding, as well as many others.
Hinds Instruments specialises in technology for polarisation measurement. Its product offerings include research modules for universities, national laboratories and R&D teams, as well as complete systems for laboratory quality control and in-line production. The company’s technology can be found in applications from astronomical source measurement, to pharmaceuticals.
Horiba Scientific offers interferometric solutions for spectroscopy, ellipsometry, and surface characterisation in research and industry. The company’s Real Time Interferometric Process Monitor is designed to provide high-precision detection of film thickness and trench depth during the etching/deposition process. Depending on applications, the LEM camera includes a 670 or 905 or 980nm laser and when mounted on any dry etch/deposition process chamber with a direct top view of the wafer this generates a small laser spot on the sample surface.
Jenoptik offers a variety of optical systems, components, and modules, including lasers and optics used in metrology and industrial applications. The company can offer standard as well as bespoke solutions depending on customers needs.
The Profilm3D and Profilm3D-200 optical profilometers from KLA are designed to be affordable, non-contact, white light interferometry-based (WLI) 3D surface topography measurement systems. The latest generation includes imaging modes that are designed to extend performance and value.
Micro Laser Systems makes free-space and fibre-coupled lasers with diffraction limited performance. Lasers from 350 to 2000nm are available with accessories for expanding or focusing the beam, fibre collimators, fibre focusers, tiny collimators and splitters to integrate with the pigtailed lasers. Custom assemblies for OEM users are also available.
MKS Newport provides interferometers and associated products such as collimators, optical delay lines, fibre optic in-line polarisers, adjustable fibre optic collimators, open- and closed-loop nanofocusing objective lens mounts, sub-nanometer piezoelectric positioning resolutions, as well as fused silica interferometer flat optics.
Nikon Metrology (part of the Nikon group) offers a wide metrology product portfolio. Its range of products include optical inspection and mechanical 3D metrology solutions along with state-of-the-art vision measuring instruments and microscopes.
OptoSigma offers a wide range of optical components and systems, including mirrors, lenses, stages, and optical tables that are well suited to metrology applications.
Polytec specialises in optical measurement technology, including laser-based systems for metrology. The company’s products cover areas such as vibration measurement, surface metrology, and non-contact displacement measurement, making them suitable for applications in research and industry.
Renishaw supplies metrology and precision measurement equipment and optical systems, including laser encoders, laser calibration systems and motion control equipment. These systems are widely used for high-precision measurements in manufacturing and research environments.
Thorlabs provides a wide range of optics and photonics products, including interferometers, optical components, detectors, and measurement systems.
Zygo Corporation specialises in the design and manufacture of advanced optical metrology instruments and systems, ultraprecise optical components and assemblies, and provides electro-optical design and manufacturing services.
This is not an exhaustive list. If you provide products and solutions for optical metrology and would like your company to be included, please let us know at: editor.electro@europascience.com.
Edmund Optics: Featured optical metrology product
Superpolished Substrates for Metrology: TECHSPEC Superpolished Substrates are used in metrology applications including cavity-ring down spectroscopy, scatterometry, and in ring laser gyroscopes, as well as in UV medical applications such as eye surgery. These Substrates are superpolished on both surfaces to achieve superior surface specifications, including ≤1Å RMS surface roughness, reducing scatter, making them ideal for UV or high-power laser applications where scatter is a concern. The low scatter of these windows also allows for their use as substrates for ion-beam sputtering (IBS) coatings.
Alongside an off-the-shelf offering in various sizes, in-house manufacturing and metrology enable the production of custom sizes and shapes from 6 to 76.2mm and Surface Roughness <0.5Å. Please contact us if your application requires a Superpolished Substrate with a custom size, if you are interested in custom coating opportunities, or to discuss how these low scatter substrates will affect your coated optic performance. Single side superpolishing is also available.
Find out more about TECHSPEC Superpolished Substrates at the Edmund Optics website.
Knight Optical: Featured optical metrology product
Knight Optical has been a cornerstone in Optical Metrology, delivering precision solutions for over 30 years. As a global leader in providing optical components, we've made significant contributions to advancing optical metrology applications.
What sets us apart is our state-of-the-art metrology laboratory, equipped with cutting-edge instruments including the Varian Cary 5000 Spectrophotometer, ZYGO Verifire XPZ Interferometer System + Radius Slide, and more.
We've recently augmented our capabilities with a range of specialised optics, including custom solutions and stock components such as precision filters, beamsplitters, mirrors, optical lenses, and prisms. Committed to excellence, our metrology lab, coupled with our meticulous QA department, guarantees the quality and precision that define Knight Optical.
Visit our website to explore our comprehensive catalogue, including the latest additions, and experience the precision and reliability that our metrology lab ensures.
For inquiries and tailored solutions, contact our UK and US teams, or find out more information by visiting the website.
