Biological materials probed by the temporal and angular profiles of the backscattered ultrafast laser pulses

Temporal and angular profiles of backscattered pulses are introduced as a practical, novel, and noninvasive technique to probe biological materials. The optical properties of these materials are quantitatively measured in terms of two scattering-length scales: the transport mean free path and the absorption length of the light. We show that these two scattering lengths can be directly determined from an analysis of the temporal or the angular profile of the backscattered pulse intensity. Experimental results for transient light backscattering from eye, heart, lung, and breast tissues, and from a tooth and a leaf, are presented.

[1]  K. Nelson,et al.  Laser-induced phonon spectroscopy. Optical generation of ultrasonic waves and investigation of electronic excited-state interactions in solids , 1981 .

[2]  A E Profio,et al.  Light transport in tissue. , 1989, Applied optics.

[3]  G. Maret,et al.  Optical coherent backscattering by random media : an experimental study , 1988 .

[4]  R. Alfano,et al.  Weak localization of photons: contributions from the different scattering pathlengths , 1989, IEEE Photonics Technology Letters.

[5]  A. Ishimaru,et al.  Retroreflectance from a dense distribution of spherical particles , 1984 .

[6]  Arya,et al.  Coherent backscattering of a picosecond pulse from a disordered medium: Analysis of the pulse shape in the time domain. , 1989, Physical review. A, General physics.

[7]  Etemad,et al.  Weak localization of photons: Termination of coherent random walks by absorption and confined geometry. , 1987, Physical review letters.

[8]  B. Greene,et al.  Generation of optical pulses shorter than 0.1 psec by colliding pulse mode-locking , 1981, IEEE Journal of Quantum Electronics.

[9]  Rudolf Sprik,et al.  Femtosecond time-resolved measurements of weak localization of light , 1988 .

[10]  A Ishimaru,et al.  Backscattering of a picosecond pulse from densely distributed scatterers. , 1979, Applied optics.

[11]  B. Wilson,et al.  Time resolved reflectance and transmittance for the non-invasive measurement of tissue optical properties. , 1989, Applied optics.

[12]  A J Welch,et al.  Practical models for light distribution in laser‐irradiated tissue , 1987, Lasers in surgery and medicine.

[13]  Freund,et al.  Precision determination of the line shape for coherently backscattered light from disordered solids: Comparison of vector and scalar theories. , 1987, Physical review. A, General physics.

[14]  Wolf,et al.  Weak localization and coherent backscattering of photons in disordered media. , 1985, Physical review letters.

[15]  Drake,et al.  Observation of nonclassical optical diffusion. , 1989, Physical review letters.

[16]  Watson,et al.  Searching for photon localization in the time domain. , 1987, Physical review letters.

[17]  A E Profio,et al.  Contrast in diaphanography of the breast. , 1988, Medical physics.

[18]  Lagendijk,et al.  Observation of weak localization of light in a finite slab: Anisotropy effects and light path classification. , 1987, Physical review letters.

[19]  R A Elliott,et al.  Multiple scattering of optical pulses in scale model clouds. , 1983, Applied optics.

[20]  S Nioka,et al.  Comparison of time-resolved and -unresolved measurements of deoxyhemoglobin in brain. , 1988, Proceedings of the National Academy of Sciences of the United States of America.

[21]  Etemad,et al.  Weak localization of photons: Universal fluctuations and ensemble averaging. , 1986, Physical review letters.

[22]  Wolf,et al.  Coherent backscattering of light by disordered media: Analysis of the peak line shape. , 1986, Physical review letters.

[23]  S L Jacques,et al.  Time resolved propagation of ultrashort laser pulses within turbid tissues. , 1989, Applied optics.

[24]  A. Lagendijk,et al.  Observation of weak localization of light in a random medium. , 1985, Physical review letters.

[25]  Stephen,et al.  Rayleigh scattering and weak localization: Effects of polarization. , 1986, Physical review. B, Condensed matter.