Higher pulse frequency of near-infrared laser irradiation increases penetration depth for novel biomedical applications

摘要

Background The clinical efficiency of laser treatments is limited by the low penetration of visible light used in certain procedures like photodynamic therapy (PDT). Second Harmonic Generation (SHG) PDT is an innovative technique to overcome this limitation that enables the use of Near Infrared (NIR) light instead of visible light. NIR frequency bands present an optical window for deeper penetration into biological tissue. In this research, we compare the penetration depths of 405 and 808 nm continuous wave (CW) lasers and 808 nm pulsed wave (PW) laser in two different modes (high and low frequency).