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Spectral determination of a two-parametric phase function for polydispersive scattering liquids
Tobias Lindbergh1, Ingemar Fredriksson, Marcus Larsson
1Division of Biomedical Instrumentation, Department of Biomedical Engineering, Linköping University, Linkoping, Sweden. tobli@imt.liu.se
Optics Express
|February 4, 2009
Summary
This study presents a new method to accurately measure diffuse reflectance in scattering media using spectral measurements and inverse Monte Carlo techniques. The approach provides reliable phase function determination, crucial for understanding light transport in complex materials.
Area of Science:
- Biomedical Optics
- Light Scattering
- Photonics
Background:
- Accurate characterization of light scattering in polydispersive media is essential for applications in biomedical imaging and material science.
- Existing methods for diffuse reflectance measurement often face challenges at small source-detector separations.
- The Gegenbauer-kernel phase function offers a robust model for describing light propagation in scattering environments.
Purpose of the Study:
- To develop and validate a method for determining a two-parametric Gegenbauer-kernel phase function.
- To accurately describe diffuse reflectance in polydispersive scattering media, particularly at small source-detector separations.
- To assess the impact of different calibration techniques on measurement accuracy.
Main Methods:
- Spectral collimated transmission measurements.
- Spatially resolved spectral diffuse reflectance (SRDR) measurements.
- Inverse Monte Carlo (IMC) technique for phase function determination.
- Absolute and relative calibration of SRDR spectra using polystyrene microspheres and fiber characterization.
Main Results:
- The proposed method accurately determines the Gegenbauer-kernel phase function for scattering media.
- Both absolute and relative calibration methods yielded comparable results for diffuse reflectance measurements.
- Deviations between simulated and measured spectra were less than 6.5% (absolute calibration) and 2.5% (relative calibration) for milk dilutions.
- For milk with an absorber (ink), deviations were 13.4% (absolute) and 7.3% (relative).
Conclusions:
- The developed method effectively characterizes diffuse reflectance in polydispersive media, even at very small separations.
- Relative calibration of SRDR spectra offers improved accuracy, especially in the presence of absorbers.
- This technique provides a valuable tool for quantitative optical property determination in complex scattering samples.
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