Abstract

Efficient two-photon photodynamic therapy (PDT) requires both high peak power of laser output and a considerable depth of light penetration into the tissue. Importance of Ti:Sapphire lasers for two-photon PDT is stipulated by the fact that their output wavelength fits into a window of relative transparency for biological tissues, and the possibility of shortpulsed output, including femtosecond pulses, allows one to reach the 1-100 kW (and more) peak power without any additional amplification. However, application of femtosecond Ti:Sapphire lasers in two-photon PDT [1] are limited because of a rapid lengthening of pubes as they travel through tissues and even through beam delivery systems This leads to substantial fall in their peak power.

© 2000 IEEE