High-resolution 3D Optical Profilometry

Nowadays, 3D optical profilometry is faced with increasing demands concerning resolution and measuring uncertainty. Optical approaches, especially interferometric and confocal techniques, are promising candidates to meet these demands. The measurement technology group deals with new instrumental configurations and signal analysis to get rid of systematic measurement uncertainties and to enhance resolution.

Amongst others, a high-resolution Linnik interferometer with 100x microscope objective lenses is being developed, which achieves a lateral resolution of 0.3 µm. Using a digital micromirror device (DMD) or LEDs of different color for illumination or putting microspheres onto the measuring object provide new options for improvement.

Improved measurement results can be also reached through extended and optimized signal processing strategies, or by analyzing measurement data in the three-dimensional spatial frequency domain.

Furthermore, measuring systems (Mirau- and Michelson interferometers) have been built for special applications, for example using a high-speed line-scan camera for dynamic measurements.

L. Hüser, P. Lehmann
Microsphere-assisted interferometry with high numerical apertures for 3D topography measurements
Applied Optics 59.6 (2020): 1695-1702

P. Lehmann, S. Tereschenko, B. Allendorf, S. Hagemeier, L. Hüser
Spectral composition of low-coherence interferograms at high numerical apertures
JEOS-RP (2019) 15:5

B. Allendorf, E. Käkel, Uh-Myong Ha, S. Hagemeier, H. Hillmer, P. Lehmann
Adaptive high-resolution Linnik interferometry for 3D measurement of microparticles
Optics Letters 44 (2019) 3550-3553

H. Knell, S. Laubach, G. Ehret, P. Lehmann
Continuous measurement of optical surfaces using a line-scan interferometer with sinusoidal path length modulation
Optics Express 22, Issue 24 (2014) 29787-29798