Fraunhofer Institute for Applied Optics and Precision Engineering IOF
Fraunhofer Institute for Applied Optics and Precision Engineering IOF

Surface and Thin Film Characterization

Comprehensive Analysis of Optical Surfaces and Components

Fraunhofer IOF has established a comprehensive expertise and metrology platform for the characterization of surfaces and thin films. This includes systems and methods for analyzing nano- and microstructures as well as optical and functional properties. A major focus is on highly sensitive methods for determining optical losses such as light scattering and absorption as well as the investigation of structure-property relationships.
Both commercial tools and special in-house developments are used. Depending on the application, we develop and apply high-quality, adaptable analysis methods that yield maximum insight while ramaining cost-effective and practical, if needed. This results in customer-specific system solutions and analysis programs that efficiently support the development of functional surfaces, thin films and materials.

Your Partner for Optical Characterization

Our team has more than 30 years of experience in the characterization of surfaces and coatings. We work closely with companies and institutions from various fields such as optics manufacturing, space & astronomy or semiconductor lithography. We specialize in adapting investigation programs and methods to the specific requirements of our customers in order to provide them with the best possible support for their questions and developments.

We offer:

  • Problem solutions for optical components and surfaces through combined measurement technology and tailored analysis programs
  • Development of customized measurement systems and sensors
 

Our Main Services and Expertise

© Fraunhofer IOF
Surface properties are correlated.

We combine different modeling approaches, measurement techniques and analysis methods tailored for the specific needs and application. Our focus is on characterizing the structural, optical and functional surface and layer properties as well as the relationships between them. This way, we can comprehensively clarify causes and correlations providing the basis for optimizing manufacturing processes.

 

Our Characterization Spectrum includes:

Analysis of Structural Properties

 

Roughness and Topography Analysis

 

We combine various high-resolution measurement methods such as atomic force microscopy or white-light interferometry for a comprehensive roughness characterization.

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Defect Detection and Analysis

 

In addition to standard methods of microscopic defect analysis, we use application-specific methods for defect and particle detection on optical components using light scattering.

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Coating Morphology and Composition

 

Structures down to the nanometer range can be imaged using scanning electron microscopy. X-ray microanalysis (EDX) allows the chemical composition to be determined.

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Analysis of Optical Properties

 

Light Scattering Characterization

 

Angle-resolved light scattering measurements allow highly sensitive, comprehensive investigation of optical losses and their causes.

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Absorption Measurement

 

“Laser Induced Deflection” (LID) is a photothermal method for highly sensitive and absolute measurement of light absorption in optical materials, coatings and fibers.

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Reflectance, Transmittance & Optical Layer Parameters

 

In addition to spectrophotometry and ellipsometry, we use cavity ring-down spectroscopy to analyze even ultra low-loss mirrors with high precision.

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Analysis of Functional Properties

 

Laser Stability

 

We combine laser stability tests with angle-resolved light scattering analysis for defect-sensitive determination of the laser damage threshold.

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Mechanical Properties & Resistance

 

Resistance is a key quality feature of thin coatings, particularly with regard to practical use. We test for adhesion, scratch resistance and environmental resistance, among other things.

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Wetting Analysis

 

Our measurement and analysis methods enable targeted structure specification and control for optimum hydrophobic surface properties.

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Our Expertise for your Application

Our versatile characterization methods support your development across a broad range of industries. We have extensive experience and cross-disciplinary expertise to address specific questions and technical challenges:

Optical Components

 

Our Expertise:

  • Analysis of surface and coating roughness in relation to the optical loss effect
  • Analysis of surface and volume scattering of optical components
  • Absolute absorption measurement of optical materials, coatings, laser crystals, etc.; determination of OH content
  • Detection of surface defects and sub-surface damage (SSD)
  • In-situ sensor technology for process control and optimization

Projects and Activities:

Development of a robot-guided light scattering sensor system for in-situ process control in mirror production

Astronomy & Space

 

Our Expertise:

  • Roughness analysis over a wide spatial frequency range (LSFR - MSFR - HSFR)
  • Light scattering analysis of telescope mirrors, flight hardware, black surfaces, apertures, etc.
  • Light scattering data (BSDF) for stray light analysis
  • Modeling and analysis of contamination-induced scattered light (PAC/ MOC)
  • Climate and environmental tests for space optics

Projects and Activities:

Analysis of contamination-induced light scattering (ESA project)

Laser & High-power Optics

 

Our Expertise:

  • Combinative loss analysis (light scattering, absorption, residual transmission/reflection) down to the sub-ppm range
  • Highly sensitive detection of surface defects and sub-surface damage
  • Linking of LIDT with light scattering and absorption properties

Projects and Activities:
As part of various interdisciplinary projects, we are involved in the development of the next generation of low-loss high-performance optics for laser fusion. Among others:

Project SHARP

© Fraunhofer IOF
In-situ roughness measurement for high-precision mirror manufacturing.
© Fraunhofer IOF
Measuring a satellite mirror for earth observation.
© Fraunhofer IOF
Lase-induced fluorescence.

Semiconductors & Lithography

 

Our Expertise:

  • Roughness analysis over a wide spatial frequency range (LSFR - MSFR - HSFR)
  • Comprehensive characterization of EUV components (collector, mask blanks): light scattering, diffraction efficiency, roughness
  • Absorption and light scattering measurements at DUV/VUV wavelengths
  • Laser-induced fluorescence (LiF)

Projects and Activities:

With stray light for perfect optics

Biology & Medicine

 

Our Expertise:

  • Light scattering analysis for contact- and label free cell detection down to the single cell
  • Light scattering sensors for microfluidic biochips (lab-on-a-chip)
  • Structure and wetting analysis for biocompatible surfaces

Projects and Activities:

Innovative Light scattering technology for the analysis of microbial cells

Automotive & Consumer

 

Our Expertise:

  • Spectral analysis of optical properties of components for headlights, LiDAR, foils/films, etc.
  • Determination of optical density, haze and gloss
  • In-situ sensor technology for process control and optimization
  • Evaluation of scratch resistance for various surfaces in the automotive, eyewear, precision-optics sectors, etc.

Projects and Activities:

Combinative inline sensor technology in the R2R process to ensure the color fidelity of thin-layer safety films

© Fraunhofer IOF
Measurement of an EUV collector mirror.
© Fraunhofer IOF
Sensor technology for microfluidic cell analysis.
© Fraunhofer IOF
Light scattering of a gemstone.
 

The Benefits of Working with Us

 

We are a team of capable, motivated sientists with many years of experience and various specialist backgrounds (physicists, engineers, materials scientists, etc.). We provide solution-oriented support for your inquiries by selecting suitable characterization methods and strategically combining diverse measurement and analysis approaches.

We continuously advance our technologies—always with an eye on our customers’ applications and requirements. Based on our extensive know-how, we combine experimental data with simulations and theory, and deliver a clear, application-focused interpretation of the results.

 

Technical Equipment for Characterization

An extensive pool of more than 50 measuring and testing systems for the characterization of optical, structural, chemical and functional surface and coating properties is available. Both commercial tools and special in-house developments are used:

 

© Fraunhofer IOF
LID-setup (laser-induced deflection) for highly sensitive absorption measurements

Our Reserch Strength

Research Reports

The research strength of our experts is reflected in the articles in the Fraunhofer IOF Annual Report. Each year, the report presents selected research results from the previous year (Archive Annual Reports). Here you will find articles on developments in the field of Surface and thin film characterization from recent years:

  • »Prediction of contamination induced stray light in optical systems«
    (Annual Report 2024, page 44-45)
  • »Non-destructive testing of subsurface damage«
    (Annual Report 2022, page 50-51)
  • »Particle and thin film growth inspection in optics fabrication«
    (Annual Report 2022, page 54-55)
  • »Deformable mirrors with excellent scattering properties«
    (Annual Report 2021, page 58-59)
  • »Contamination budgets and their impact on light scattering«
    (Annual Report 2020, page 72-73)
  • »Optical properties of ultrathin evaporated metal films«
    (Annual Report 2019, page 46-47)
  • »Customized light scattering tools for every application«
    (Annual Report 2019, page 50-51)

Do you have questions about our services?  

In a personal meeting, we will advise you on our (individual) range of services and our core competencies. Please contact us. 

Obtain consultation

Are you interested in a cooperation? Contact us!

We develop special and visionary solutions - tailored to the needs and wishes of our customers. Let us talk about your idea(s).

 

Find solution

You would like to work with us?
Then apply with us!

We are always looking for creative minds and committed people who want to develop innovative solutions with light together with us. Visit our job portal or send us a speculative application:

Become part of the team

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