Work

Phase analysis method for characterizing absorption in turbid media: theory, simulations, and TiO 2 phantom experiments

Year: 2026

Type: article

Abstract: Separating absorption and scattering in turbid media remains a major challenge in optical characterization. This work takes a step toward addressing it by applying non-contact estimation of the absorption coefficient ( µ a ) within a phase-analysis framework originally developed for extracting the reduced scattering coefficient ( μ s ′ ). The iterative multi-plane optical properties extraction (IMOPE) technique reconstructs diffuse-reflectance (DR) phase from multi-plane intensity measurements, enabling phase-based analysis for μ s ′ extraction. Here, the DR model is extended to incorporate sensitivity to variations in µ a , establishing a route for phase-driven absorption assessment, demonstrating opposing trends for µ a and μ s ′ increments. Monte Carlo simulations and TiO 2 -based phantoms with independently controlled μ s ′ and µ a validate the theoretical predictions. This study experimentally validates a phase-based µ a extraction scheme at λ 1 = 473 nm, with cross-wavelength verification at λ 2 = 632.8 nm, demonstrating strong agreement, 91%, 95% for λ 1, λ 2 , respectively, between extracted and designed absorption values. A detailed TiO 2 phantom preparation protocol is provided to support experimental reproducibility. Finally, we present an initial framework for estimating µ a from the reconstructed phase, laying the groundwork for future quantitative separation of absorption and scattering in turbid media.

Source: Optics Express

DOI: 10.1364/oe.588955

Authors: Channa Shapira, Bar Atuar, Yuval Haibi, Hamootal Duadi, Dror Fixler

Institution: Tel Aviv University

Language: English

Topic: Optical Imaging and Spectroscopy Techniques

Subfield: Radiology, Nuclear Medicine and Imaging

Field: Medicine

Domain: Health Sciences

Open Access status: gold

Estimated APC paid: $2,270

Funder: Israel Science Foundation