Photon transport in cylindrically-shaped disordered meso-macroporous materials

Area of Science:

• Optics and Photonics
• Materials Science
• Biomedical Optics

Background:

• Disordered meso-macroporous materials are crucial for light diffusion studies.
• Biological tissues and certain engineered materials exhibit similar porous structures.
• Understanding light transport in finite-sized porous media is vital for applications.

Purpose of the Study:

• To investigate light diffusion in finite-sized cylindrical porous materials.
• To develop and validate a model accounting for lateral size effects.
• To differentiate geometrical scattering from material absorption.

Main Methods:

• Theoretical modeling of light diffusion in finite cylinders.
• Monte Carlo random walk simulations for model validation.
• Steady-state and time-resolved transmission experiments on HIPE silica foams.
• Fitting experimental data to retrieve transport parameters.

Main Results:

• An analytical model for light diffusion in finite cylinders was developed and validated.
• Experimental transmission and photon lifetime were measured.
• Lateral scattering losses were shown to mimic material absorption effects.
• Transport parameters (mean free path, absorption length) were successfully retrieved.

Conclusions:

• Geometrical effects from finite sample size significantly influence light transmission and photon lifetime.
• Misattributing lateral scattering to material absorption can lead to erroneous conclusions.
• Accurate characterization is essential for applications in biological imaging and energy conversion.