Label-free imaging of thick tissue at 1550 nm using a femtosecond optical parametric generator

摘要

We have developed a simple wavelength-tunable optical parametric generator (OPG), emitting broadband ultra-short pulses with peak wavelengths at 1530-1790 nm, for nonlinear label-free microscopy. The OPG consists of a periodically poled lithium niobate crystal, pumped at 1064 nm by a ultrafast Yb: fiber laser with high pulse energy. We demonstrate that this OPG can be used for label-free imaging, by third-harmonic generation, of nuclei of brain cells and blood vessels in a >150 mu m thick brain tissue section, with very little decay of intensity with imaging depth and no visible damage to the tissue at an incident average power of 15 mW. (C)2015 Optical Society of America