M/F Wide-Field Coherent Raman Microscopy: Application to Semiconductor Imaging

Job Description

Missions

The Fresnel Institute has developed a wide-field coherent anti-Stokes Raman scattering (CARS) imaging technique using speckle illumination [1]. This method employs low-repetition-rate lasers (∼100 kHz) with high pulse energy (microjoule range) to generate random speckle patterns for both the pump and Stokes beams. By rapidly varying the speckle illumination of the pump beam, the CARS signal generation can be rendered incoherent, thereby achieving a depth of field comparable to that of microscopes using incoherent light. This approach enables video-rate CARS chemical imaging over fields of view exceeding 200 µm. The technique can also be extended to achieve optical sectioning at the micron scale and super-resolution imaging (twice the diffraction limit). This is accomplished by acquiring sequential speckle illumination images and processing them using Random Illumination Microscopy (RIM).
This wide-field CARS chemical imaging technique has been successfully applied to biological samples using near-infrared lasers in the 700–900 nm range.

Activity

The goal of this research is to extend wide-field CARS chemical imaging techniques to the infrared domain, specifically for pump and Stokes beams with wavelengths above 1.4 µm. In this spectral range, it becomes possible to image semiconductor components.
Semiconductor materials exhibit vibrational modes that depend on their crystal lattice and crystallographic symmetry. Imaging these modes over large fields should reveal mechanical stresses, doping effects, and local temperature variations.
Thus, this project aims to develop a wide-field coherent Raman microscope capable of imaging centimeter-scale areas of semiconductor materials.

[1] Fantuzzi, E.M., Heuke, S., Labouesse, S. et al. Wide-field coherent anti-Stokes Raman scattering microscopy using random illuminations. Nat. Photon. 17, 1097–1104 (2023). https://doi.org/10.1038/s41566-023-01294-x

Your Profil

Skills

The research program will focus on three main objectives:
1. Experimental Development: Design and implement a wide-field coherent Raman imaging system.
2. Validation: Demonstrate the technique's effectiveness by imaging the 520 cm⁻¹ silicon Raman line.
3. Exploration: Investigate the vibrational modes of other semiconductor materials (e.g., h-BN, MoS₂, GaN).
Expertise in:
- Experimental optics
- Data processing
are expected

Your Work Environment

The project is part of an H2020/ERC research program

Compensation and benefits

Compensation

between 3131,31 € and 4341,70 € gross salary depending on experience

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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