Conventional 3D metrology systems usually operate at wavelengths around 800 nm due to the human eye's blindness in this spectral region. However, hazard potential is rather high at these wavelengths as the eye is highly transparent up to about 1400 nm of wavelength, thus impeding tightly linked human-machine interactions relying on the three-dimensional recognition of human beings, e.g. their mimics and gestures, by empathic machine systems.
To solve this problem, the research group Eye-safe 3D metrology in the SWIR seeks to establish a both high-performant and cost-efficient 3D metrology working in the Short-Wavelength Infrared (SWIR), particularly at around 1450 nm. At these wavelengths, the optical absorption of water (for example by the tear film on the human's eye) represents a natural protection mechanism for hazardous, high intensity optical irradiation, therefore allowing for around 2 orders of magnitude higher maximum admissible optical intensities according to DIN EN 60825-1.
A major requirement for eye-safe metrology systems is the availability of cost-efficient SWIR sensors. For that, one major focus of our work is the development of CMOS capable Germanium-on-Silicon (Ge-on-Si) sensors for normal incidence and maximization of their optical responsivity by means of diffractive light-trapping structures.
Further efforts, undertaken in close cooperation with external partners from research and industry, comprise the design and demonstration of novel 3D metrology systems operating in the SWIR.

Bild1_Martin Steglich
Figure: Schematic illustration of a Ge-on-Si photodiode with diffractive "Black Silicon" light-trapping
structure. The sensor is illuminated via the sensor rear side where the Black Silicon is located, yielding
a strong light-trapping effect and, thus, a drastically increased light absorption in the device.

This Junior Research Group "Augensichere 3D-Messtechnik im SWIR (3D-SWIR)", funded by the German Federal Ministry of Education and Research (BMBF), contract no. 03ZZ0435, is part of the innovation alliance "3Dsensation" ( >> link ). "3Dsensation" is a  consortium consisting of industry partners and research institutions from different branches of science. This consortium fosters interdisciplinary research and development work with the aim to tackle central technical, sociological and ethical challenges of man-machine interaction.


This project is cofinanced by the joint research project "Nachtsichtkamera für automotive Anwendungen (NASIKA)" German Ministry of Education and Research (BMBF), contract no.: 03VP00413.

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