Led by Fedele Pisani, a PhD student at Politecnico di Milano and Industrial PhD candidate at Cambridge Raman Imaging, a team of CHARM project partners, including CNR’s Institute for Photonics and Nanotechnologies, has made a technical breakthrough in fiber laser design for biomedical imaging using Coherent Raman platforms.
Published in Optics Express, the open-access study details the development of a compact, all-polarization-maintaining-fiber Nd-doped laser that operates at 920 nm—an important wavelength for accessing the “fingerprint region” in broadband stimulated Raman scattering (SRS) microscopy. This spectral region carries highly specific molecular information essential for distinguishing cancerous from healthy tissue.
What sets this laser apart is its compactness, spectral precision, and stability. It delivers stable ultrafast pulses with less than two picoseconds of timing jitter and just 0.04% intensity noise—key metrics for reliable medical imaging. Even more impressively, the team demonstrated passive synchronization with a Yb-doped oscillator, a crucial step for integrating the laser into CHARM’s multimodal broadband SRS imaging platform.
Applying the research to CHARM
“My work in the CHARM project focuses on extending Coherent Raman technology into the fingerprint region, which offers deeper molecular insight,” explains Fedele. “Developing a low-noise 920 nm pump source that is passively synchronized with a broadband 1030 nm Stokes source is an essential step toward this goal— it meets all laser source requirements for Raman imaging in the fingerprint region.”
As part of CHARM’s broader vision, this new laser could help bring complex Raman-based diagnostics closer to practical biological applications.
Next steps
The team is now working to integrate the new laser into the full SRS microscopy setup, enabling simultaneous acquisition of the CH and fingerprint regions for more comprehensive and informative tissue imaging.