Metrology of Micro- and Nanooptics

The wafer inspection microscope is used to examine optical components and wafers for defects, cracks, and contamination. Various illumination modes (transmitted light, reflected light, dark field, UV) enable even the finest defects to be detected.

Our Services

• Automated defect scanning and defect analysis (according to ISO10110)
• Full-surface, high-resolution image assembly (up to 200 × 300 mm)
• Crack analysis, mappings, documentation
• Microscope magnification: 1.6× to 150×

Scanning electron microscopy (SEM) with integrated focused ion beam (FIB) enables high-resolution imaging and material analysis of micro- and nanostructured surfaces. Structural sections can be prepared and examined in cross-section. Various detectors provide information on topography, material contrast, and crystal structure.

Our Services

• High-resolution imaging (resolution up to <3 nm)
• Examination on large substrates (230x230x9 mm Please ask us!)
• Preparation and analysis of cross sections via focused ion beam (FIB)
• Material analysis using EDX (elemental analysis) and EBSD (crystal orientation)
• Scanning transmission electron microscopy (STEM)
• Deposition of protective layers or addition of reactive etching gases (GIS)
• Analysis of structural defects and layer systems

AFM enables three-dimensional scanning of surfaces with resolution down to sub-nanometer scale to reveal fine micro- and nanopatterns or surface roughness.

Our Services

• Automated measurement ranges on substrates up to 300 × 300 mm
• Measurement of structure heights up to 13 µm
• Determination of surface roughness (RMS down to <1 nm)
• Depth measurement of structures from approx. 100 nm width
• Analysis of aspect ratios up to approx. 1:7

Tactile and non-contact methods are available for recording surface topography to analyze dimensional accuracy and roughness in different frequency ranges. Depending on the material and structure, one method is usually more suitable than another. Beyond superficial analysis, the preparation of cross-sections can be done (sawing and subsequent polishing) for visual inspection with a high-resolution light microscope.

Stylus profilometer

• Tactile measurement with scan lengths up to 200 mm
• Automated shape analysis of microlenses and prisms
• High-precision step height measurement
• Roughness measurement in accordance with ISO standards (e.g., Ra, Rz)

White light interferometry

• Non-contact measurements (stitching) and measuring ranges
• Best height resolution
• Measurements on structured layers (transparent layers)
• Roughness measurement according to ISO standards (e.g., Ra, Rz, Sa, Sq)

Laser scanning microscopy (confocal microscope)

• Non-contact measurement with different wavelengths (R, G, B, UV)
• Best lateral resolution
• Detection of steep structural edges
• Measurements on structured layers (transparent layers)
• Roughness measurement according to ISO standards (e.g., Ra, Rz, Sa, Sq)

The PSI enables high-precision measurements of the flatness and wavefront errors of optical components. By applying a defined phase shift to coherent laser radiation and capturing interference fringes, the surface shape can be reconstructed with sub-nanometer resolution on extendet areas.

Our Services

• Interferometer: 12" ZYGO GPI XP HeNe@632.8 nm
• Measurement of flatness (SFE) and wavefront error, in reflection (rWFE) and transmission (tWFE)
• Optical zoom up to 6:1, measurement field up to 300 mm diameter
• Reflection and transmission holders for different sample sizes
• Wavefront determination of grating structures in diffraction order
• High-resolution stitching measurements
• Optional: Various other interferometer types (6“ FTPSI ZYGO MST; 6” PSI ZYGO Dynafiz; 6" stitching interferometer ZYGO MetroStation)

Scattered Light Metrology enables detailed analysis of the scattering behavior of micro- and nanostructured optical elements such as diffraction gratings, metaoptics, and CGHs. This involves determining the intensity distribution (angle-resolved scattering) and the efficiency of individual diffraction orders (angle-resolved efficiency) in an angle-resolved manner. This method is essential for assessing optical quality and minimizing stray light in high-performance applications.

Our Services

• Angle-resolved scattered light metrology (0° to >70°) along a plane
• Quantitative determination of efficiency for individual diffraction orders
• Analysis of near-angle ghosts and unwanted diffraction maxima
• Characterization of diffractive optics, meta-optics, CGHs, diffraction gratings
• Consulting on optimization of scattered light behavior

Extensive options for scattered light characterization at Fraunhofer IOF can be found here.

Efficiency metrology quantifies the proportion of incident light that is directed into the desired diffraction orders. The measurement is performed using laser or white light sources and enables precise analysis of the optical performance and evaluation of the manufacturing quality of optical gratings. Measurements can be performed in reflection and transmission.

Our Services

• Polarization-sensitive diffraction efficiency measurement at discrete laser wavelengths (UV-SWIR)
• Broadband measurement using a tunable white light source (450–1600 nm)
• Automated sample mapping (xy, 300 × 250 mm, resolution 2 mm)
• Highly sensitive detection with UV/VIS/NIR/SWIR photodetectors
• Measurements and determination of polarization sensitivity

Ellipsometry measures the change in polarization of light during reflection or transmission, enabling the determination of layer thicknesses, optical constants, and structural parameters of diffraction gratings and metamaterials. Combined with RCWA simulations, complex gratings and metasurfaces can be analyzed with precision.

Our Services

• Measurement and evaluation of the psi-delta parameters or Stokes parameters S1(λ, θi, φ) and S2(λ, θi, φ) for linearly polarized light (+45°, –45°)
• Modeling of microstructures and MSE fitting to determine geometric structure parameters, dispersion data, and layer thicknesses
• Support through RCWA simulation for modeling complex structures
• Characterization of metaoptics, diffraction gratings, layer systems

With the aid of a calibrated camera measuring site, the intensity distribution can be evaluated with a single image capture (snapshot). This measuring principle is used to examine micro-optical beam shapers and splitters, particularly with regard to intensity homogeneity and angular range. Various light sources in the VIS and NIR are available.

Our Services

• Homogeneity Metrology
• Luminance Distributions

The combination of state-of-the-art characterization and advanced simulation technology provides customers with precise feedback on their circuit design. This enables optimization of patterns, shortens development cycles, and ensures that new photonic components reach the market faster, more reliably, and with maximum performance.

Our Services

• Passive: Coupling efficiency, spectral transfer functions, damping losses, mode profiles, resonator properties
• Active: RF and modulator measurements (bandwidths, Vπ·L, thermal tuning)
• Nonlinear: SHG/DFG/OPA, conversion efficiency, nonlinear coefficients, poling/domain quality
• Wafer/chip: automated optical and RF probing, standardized reports
• Infrastructure: CW/pulse sources, broadband sources, spectrometers, highly sensitive detectors
• Simulation: Sophisticated methods for modeling linear and nonlinear waveguide properties, enabling the design of complex hybrid components