Generation depth modeling in time domain diffuse Raman spectroscopy: the homogeneous case

Area of Science:

• * Spectroscopy and Photonics
• * Biomedical Optics

Background:

• * Accurate depth profiling is crucial for interpreting Raman spectroscopy data, especially in biological tissues.
• * Existing models may not fully account for wavelength-dependent optical properties.
• * Time domain diffuse Raman spectroscopy (TD-DIRS) and spatially offset Raman spectroscopy (SORS) are valuable non-invasive techniques.

Purpose of the Study:

• * To develop a rigorous analytical model for calculating the average generation depth of Raman photons.
• * To investigate the dependence of generation depth on photon time-of-flight and source-detector distance.
• * To enhance the interpretation of TD-DIRS and SORS measurements.

Main Methods:

• * Development of an analytical model based on the diffusion equation.
• * Inclusion of wavelength-dependent optical property variations.
• * Validation using Monte Carlo simulations.

Main Results:

• * The model accurately calculates average Raman photon generation depth.
• * Generation depth is quantified in relation to photon time-of-flight (TD-DIRS) and source-detector distance (SORS).
• * Simulations of in vivo scenarios demonstrate the model's applicability.

Conclusions:

• * The proposed model provides fundamental knowledge for improving SORS and TD-DIRS data interpretation.
• * It offers a more accurate estimation of probed depth in diffusive media.
• * This advancement is critical for applications in biomedical diagnostics and research.