Advanced optical diagnostics

Optical diagnostics are techniques of choice for cold plasma studies due to the diversity of accessible parameters and their non-intrusive nature. The team develops and adapts advanced techniques from low pressure to atmospheric pressure plasmas, including DC and nanosecond discharges.

Examples include:

• Cavity Ring-Down Spectroscopy (CRDS) probing a forbidden dipole transition of oxygen atoms

• High spectral resolution TALIF

• Photodetachment for negative ion detection in PEGASES thrusters

• Thomson scattering in plasma jets

• In situ IR transmission and Raman scattering under plasma exposure

• VUV absorption at the SOLEIL synchrotron

• In situ Mueller polarimetry

• High-speed imaging of self-organization phenomena

Beyond implementation, the team aims to improve diagnostic sensitivity, cross-validate measurements with redundant techniques, and quantify technique limitations.