Optical Review

, Volume 19, Issue 3, pp 159–166

Study on mechanism of ultrasonic fluorescence modulation in light scattering medium based on diffusion approximation with varying refractive index

  • Trinh Quang Duc
  • Shunsuke Kaneta
  • Masaki Kobayashi
Regular Papers

DOI: 10.1007/s10043-012-0027-5

Cite this article as:
Duc, T.Q., Kaneta, S. & Kobayashi, M. OPT REV (2012) 19: 159. doi:10.1007/s10043-012-0027-5

Abstract

In this study, we propose a model to describe the mechanism of ultrasonic fluorescence modulation based on the application of a modified diffusion approximation, which is derived from the radiative transfer equation with consideration of the varying refractive index. The model was evaluated by computation with finite element method (FEM) to simulate the physical phenomena of our previous experiments. The simulation shows that the measured power of the modulated fluorescence signal at the boundary of 40-mm-thick light scattering medium (scattering coefficient and anisotropy factor of 1.36mm−1 and 0.67, respectively) with the fluorophore located at the center was 10−20 of the incident laser power. The analysis based on the simulation results indicates the significant property of the modulation in which the modulated signal is combination including two processes generated from the variation of the refractive index and fluorophore concentration (the contributions of these are equivalent), whereas the contribution of the variation of the scattering coefficient is negligibly small. The profile of the fluorescence image and the characteristics of the quadratic relationship between the modulated intensity signal and the sound pressure are consistent with our previous experimental results.

Keywords

mechanism ultrasonic fluorescence modulation finite element method 

Copyright information

© The Optical Society of Japan 2012

Authors and Affiliations

  • Trinh Quang Duc
    • 1
  • Shunsuke Kaneta
    • 1
  • Masaki Kobayashi
    • 1
  1. 1.Department of Electronics, Graduate School of EngineeringTohoku Institute of TechnologySendaiJapan