Arbeitsgruppe Prof. Fouckhardt


The water droplets (see video above) in an opaque liquid (i.e. blackened decane) are used as optical irises.

The video gives a view onto a preliminary 3x3 test iris array (standing vertically) with 2x2 different droplet/iris positions in each subarray, switched between by electrowetting-on-dielectrics (EWOD). There is diffuse illumination from the back.

Any of the droplets belongs to one 2x2 subarray and has a volume of around 60 nl. A single subarray has dimensions of 1mm x 1mm x 0.25 mm.

The rectangular AC drive voltage is 2x 130 V peak-to-peak (response time <40 ms) and has a frequency of 5 kHz.

One of the subarrays (right bottom) is not working; i. e. the droplet does not move. In another subarray (left middle) a small air bubble is visible (having entered the subarray upon packaging), of course not actuated by EWOD, but by the movement of the main droplet.




Recent publications:


1.     J. Strassner, J. Richter, Th. Loeber, Chr. Doering, H. Fouckhardt: Epitaxial growth of optoelectronically active Ga(As)Sb quantum dots on Al-rich AlGaAs with GaAs capsule layers. Adv. Mat. Sc. & Eng. (2021) (10 pages), doi: 10.1155/2021/8862946

2.     G. Sombrio, E. Oliveira, J. Strassner, J. Richter, Chr. Doering, H. Fouckhardt: Doped or quantum-dot layers as in situ etch-stop indicators for III/V semiconductor reactive ion etching (RIE) using reflectance anisotropy spectroscopy. Micromachines, special issue on “Etching for Semiconductor Nanofabrication” 12 (2021) 502 (14 pages), doi: 10.3390/mi12050502

3.     H. Fouckhardt, Chr. Doering, M. Oulad Saiad: High shape-accuracy of surface roughnesses upon nano-moulding with optical elastomers. Opt. Mat. 118 (2021) 111230 (6 pages), doi: 10.1016/ j.optmat.2021.111230

4.     H. Fouckhardt, Chr. Doering, M. Jaax, B. Laegel: Theory, simulation, fabrication, and characterization of Galois scattering plates for the optical and the THz spectral range. AIP Advances 11 (2021) 065130 (10 pages), doi: 10.1063/5.0053843

5.     G. Sombrio, E. Oliveira, J. Strassner, Chr. Doering, H. Fouckhardt: Interferometric in-situ III/V semiconductor dry-etch depth-control with ±0.8 nm best accuracy using a quadruple-Vernier-scale measurement. J. Vac. Sci. Technol. JVST-B 39, 5 (2021) 052204 (7 pages), doi: 10.1116/6.0001209

6.     BUCH: H. Fouckhardt: Lehren und Lernen – Tipps aus der Praxis. 2., erweiterte Auflage. Springer Spektrum (2021) ISBN 978-3-662-63199-7

7.     Chr. Doering, J. Strassner, H. Fouckhardt: Microdroplet actuation via light line optoelectrowetting (LL-OEW). International J. Analyt. Chem. IJAC vol. 2021 (2021) Article ID 3402411 (9 pages), doi: 10.1155/2021/3402411


8.     J. Strassner, Chr. Doering, E. Oliveira, H. Fouckhardt: Optoelectrowetting (OEW) with push-actuation of microdroplets at small frequencies and OEW equations revisited. Sens. & Act. A: Phys. 334 (2022) Article ID 113331 (8 pages); doi: 10.1016/j.sna.2021.113331



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