Abstract

The transmission of 100-fs ultrafast laser pulses through biological tissues was measured by using femtosecond and picosecond time-resolved detection techniques. The broadening of transmitted pulses was found to increase as the thickness of the biological tissue increases. The absence of a distinct ballistic pulse transmitted through a relatively thin tissue is in sharp contrast with the pulse transmission through a random medium of discrete scatterers. Because of the continuous variation of the dielectric constant in tissue, the photons undergo scattering through the tissue, travel in various small zigzag least optical paths, and form a broadened early-arriving portion of the transmitted pulse. Even in the absence of a well-defined ballistic pulse, we can image an opaque object hidden inside a tissue as thick as 6.5 mm with submillimeter resolution by selecting the early-arriving portion of the transmitted pulse.

© 1993 Optical Society of America

Transmitted photon intensity through biological tissues within various time windows

Feng Liu, K. M. Yoo, and R. R. Alfano
Opt. Lett. 19(10) 740-742 (1994)

Ultrafast time-gated imaging in thick tissues: a step toward optical mammography

B. B. Das, K. M. Yoo, and R. R. Alfano
Opt. Lett. 18(13) 1092-1094 (1993)

Evaluation of holographic methods for imaging through biological tissue

Y. Chen, H. Chen, D. Dilworth, E. Leith, J. Lopez, M. Shih, P. C. Sun, and G. Vossler
Appl. Opt. 32(23) 4330-4336 (1993)

Femtosecond transillumination tomography in thick tissues

Michael R. Hee, Joseph A. Izatt, Eric A. Swanson, and James G. Fujimoto
Opt. Lett. 18(13) 1107-1109 (1993)

Imaging of a translucent object hidden in a highly scattering medium from the early portion of the diffuse component of a transmitted ultrafast laser pulse

K. M. Yoo, B. B. Das, and R. R. Alfano
Opt. Lett. 17(13) 958-960 (1992)