Missions

The postdoctoral researcher's activities will focus on improving infrared beam transport and focusing performances, with the aim of getting down to a spot size of less than 50 µm for chemical imaging of biological tissues by mass spectrometry.

Activités

Different strategies can be followed:
1. optimizing the quality of the transverse beam leaving the OPO for correct injection into the optical fiber;
2. testing new types of fiber (hollow-core in particular) to homogenize the beam while reducing power losses;
3. optimizing beam focusing at the fiber exit to achieve the smallest possible ablation spot size;
4. testing new imaging performances (spatial resolution, reproducibility, stability over time) on biological tissue.
The work will combine modeling with instrumental developments and experimental measurements. The solutions envisaged for optimizing laser beam injection, transport and focusing will be tested using CODE V software and/or software developed in the laboratory (Fibertech platform). In parallel, the experimental work will initially involve precise measurement of the laser's transverse profile using an infrared beam analyzer (acquired as part of the project). This analyzer will also be extremely useful for testing the performance of the proposed solutions for injection and final beam shaping. A focusing system welded directly onto the end of the fiber is also envisaged.

Compétences

- Optical and opto-mechanical design
- Nanosecond pulsed lasers (Nd:YAG) and OPO
- Optical simulations
- Fiber optics
- Mass spectrometry and chemical imaging
- English language: C1 (Common European Framework of Reference for Languages)
- Team spirit
- Dialogue and adaptability

Contexte de travail

As part of the ANR DEADPOOL (2022-2026) between three laboratories on the University of Lille campus (PRISM Inserm U1192, PhLAM CNRS UMR 8523 and CRIStAL CNRS UMR 9189), the consortium is seeking to develop an in vivo mass spectrometry (MSI) imaging system along the lines of the SpiderMass instrument with an automated processing pipeline offering automatic interpretation of chemical images for clinical diagnostic applications.
In the instrument under development, an infrared laser beam (2.9 µm) from an OPO is used to ablate species present in biological tissues. It is injected into an optical fiber for transport, then shaped at its exit to achieve a spot size of around 500 μm at present, which considerably limits the spatial resolution of the instrument.