## Abstract

This paper examines the initial transients of the radiation intensity and flux for a one-dimensional finite tissue medium where the incident source pulse is of the duration of picoseconds or less. As a first approximation the intensity field is modeled as a linear function of the cosine of the angle, and the coefficients of the linear function are functions of time and position. The mathematical form of the resultant radiative transport equations is of a hyperbolic form with a wave speed equal to 1/√3 of the speed of light in the medium. The incident source travels at the speed of light. The specific application considered is the transport of femtosecond and picosecond laser pulses through absorbing and scattering tissue, such as in the non-invasive bio-medical optical imaging that utilizes the reflected and transmitted signals. The results for a one-dimensional finite medium obtained by the method of characteristics show a distinct wave nature which asymptotes to the diffusion results at large times after the incident pulse has ended. The time dependent reflectivity and transmissivity of the medium can be correlated to the medium properties.

Original language | English (US) |
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Title of host publication | American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD |

Editors | L.J. Hayes |

Publisher | ASME |

Pages | 43-48 |

Number of pages | 6 |

Volume | 322 |

State | Published - 1995 |

Event | Proceedings of the 1995 ASME International Mechanical Engineering Congress and Exposition - San Francisco, CA, USA Duration: Nov 12 1995 → Nov 17 1995 |

### Other

Other | Proceedings of the 1995 ASME International Mechanical Engineering Congress and Exposition |
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City | San Francisco, CA, USA |

Period | 11/12/95 → 11/17/95 |

## ASJC Scopus subject areas

- Fluid Flow and Transfer Processes
- Mechanical Engineering