Link to the offer: www.dropbox.com/s/dahu6n6y5ginfex/StageMaster_ANUBIS2021_E.pdf
IRIMAS has developed a tomographic diffractive microscope (TDM), which permits to obtain three-dimensional images of transparent samples of submicron size, with a currently unmatched resolution. (Opt. Lett. 34, p. 79 (2009), J. Biophoton. 3, p. 462 (2010), Appl. Opt. 53, p. 748 (2014), Optica 4, p. 460 (2017)).
Image acquisition is a two-step process:
1) A first, data recording step, consists in acquiring holograms of the sample for different angles of illumination. This operation is performed using an optical assembly already developed in the laboratory.
2) The second step consists in a digital reconstruction, by extracting the wavefronts associated with each hologram, then recombining them, to finally inverse the diffraction problem in order to obtain the final 3-D image of the specimen.
One difficulty with the method is its calibration. For the index, one can use beads of different glasses, silica, or latex, the refractive indices of which are very well tabulated. With two reference points, the linearity of the system response guarantees the index measurement. The absorption calibration is more delicate. Relative reliance on index
calibration can be made, but the use of known absorption samples would be preferable.
The proposed master's subject will therefore consist in characterizing the silica beads calibrated in size and refractive index, and grafted with absorbent molecules by LIMA, to achieve an absorption calibration of the tomographic system developed at IRIMAS.
In a second phase, the same strategy could be applied to the grafting of photochromic compounds absorbent molecules, which absorption can be photoswitched.
This work is to be carried on in three steps:
1) Studying the underlying principles of TDM (bibliography), and becoming familiar
with the operation of the present IRIMAS systems.
2) Characterizing the beads prepared by LIMA laboratory (already available)
3) Studying/Modifying the IRIMAS set-up to image photochromic beads.
The selected candidate will join a recognized and active group in the domain (1 Professor, 3 Assistant-Professors, 1 Engineer, 2 Assistant-Engineers, 3 PhD students).
Expected skills: autonomy, resourcefulness, and creativity. Strong analytical skills (Physics, Optics), some computational skills are also necessary (C/C++, Python).
Duration: 4-6 months Gratification: 546 €/month (35h/week - 4 week/month basis)
Contact at IRIMAS:
Nicolas Verrier (Ass.-Pr)
IRIMAS - IUT de Mulhouse
61 rue Albert Camus, 68093 Mulhouse Cedex
Tél: 03 89 33 76 66
Olivier Haeberlé (Pr)
IRIMAS - IUT de Mulhouse
61 rue Albert Camus 68093 Mulhouse Cedex
Tél: 03 89 33 76 11
(c) GdR 720 ISIS - CNRS - 2011-2020.