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2.4 A better understanding of light-matter interaction: bridging the gap between micro and macro scales, and developing new devices and approaches for the North

Principal investigator

Pierre Marquet


Daniel Côté, Philippe Després


Marcel Babin

Collaborators outside U. Laval

Pierre Francus

Project summary

The accurate knowledge of light distribution in diffusive media is invaluable to understand how light shapes our environment (e.g., photosynthesis in the oceans) and helps us decipher it (e.g., diagnosis with light). Yet, despite years of advances in the field, models of light propagation in diffusive media often rely on approximations that neglect details of the microscopic structure of matter. Therefore, our models aiming at providing a comprehensive understanding of important phenomena resulting from these light-matter interactions in diffuse media fail in different situations. For example, light distribution under the ice cap would enable a better understanding of marine ecosystems. In addition, with the design of ever smaller optical probes operating in non-diffusive regime, the shortcomings of the current light transport models become apparent and amount to a lost opportunity: better models would provide more accurate tissue characterization. Considering that these modeling shortcomings result noticeably from a lack a data concerning the structural organisation of these diffusive media, we propose a strategy aiming at

1) collecting structural data with relevance to optics from both sea ice as well as biological tissues

2) feeding different radiative transfer models with these relevant structural parameters and

3) developing cutting-edge computational modeling strategies that take these microscopic parameters into account.

These new radiative transfer models will pave the way to gain substantial information about the impact of climate change on marine ecosystems, and to develop efficient miniature instruments for rapid diagnoses concerning in particular dermatological issues and circadian rhythm disorders for Northern populations.