Publication Type:Journal Article
Source:Journal of biomedical optics, Volume 11, Issue 2, p.020501 (2006)
Keywords:Algorithms, Equipment Design, Equipment Failure Analysis, Humans, Image Enhancement, Microscopy, Fluorescence, Multiphoton, Nonlinear Dynamics, Reproducibility of Results, Sensitivity and Specificity, Signal Processing, Computer-Assisted, Skin
We have developed a multiphoton microscopy (MPM) system using a 12-fs Ti:sapphire laser with adjustable dispersion precompensation in order to examine the impact of pulse duration on nonlinear optical signals. The efficiencies of two-photon-excited fluorescence (TPEF) and second harmonic generation (SHG) were studied for various pulse durations, measured at the sample, ranging from approximately 400 fs to sub-20 fs. Both TPEF and SHG increased proportionally to the inverse of the pulse duration for the entire tested range. Because of improved signal-to-noise ratio, sub-20-fs pulses were used to enhance MPM imaging depth by approximately 160%, compared to 120-fs pulses, in human skin.