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Absorbance measurements in turbid media by the photon correlation method
Applied Optics
|November 10, 2010
Summary
This study quantifies optical absorption in turbid media using photon correlation spectroscopy. The method accurately determines absorber concentration and molecular extinction coefficients, enabling absorbance measurements in complex samples.
Area of Science:
- Biophotonics
- Optical Physics
- Spectroscopy
Background:
- Quantifying optical absorption in highly turbid media is challenging due to light scattering.
- Traditional methods struggle with accurate absorbance measurements in complex biological tissues or colloidal suspensions.
Purpose of the Study:
- To develop and validate a novel method for quantifying optical absorption in turbid media.
- To establish a direct correlation between photon arrival time shifts and absorber concentration.
- To demonstrate the feasibility of absorbance measurement using photon correlation spectroscopy.
Main Methods:
- Utilized the time shift of the electric field autocorrelation function of diffused photons.
- Analyzed the intensity autocorrelation function using third-order cumulant expansion.
- Measured absorption spectra derived from photon time-of-flight shifts.
Main Results:
- Observed a linear relationship between the time shift of the autocorrelation function and absorber concentration.
- Determined the molecular extinction coefficient of the absorber from the slope of the fitted line.
- Successfully obtained absorption spectra from the time shift data.
Conclusions:
- Photon correlation spectroscopy provides a feasible method for absorbance quantification in turbid media.
- The technique allows for accurate determination of absorber concentration and optical properties.
- Potential applications include dual-wavelength absorption measurements in scattering samples.
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