In-vivo Corneal Nonlinear Optical Tomography based on Second Harmonic and Multiphoton Autofluorescence Imaging induced by Near-Infrared Femtosecond Lasers with Rabbits

摘要

The intratissue multiphoton autofluorescence imaging (MAI) and the second harmonic generation (SHG) based on nonlinear process of femtosecond nanojoule laser pulses at wave length of 750-850 nm emitted from solid-state Titanium: Sapphire Chameleon have been used as a highly precise non-destructive tool to realize the in-vivo differentiation of corneal layers with the assistance of intratissue optical tomography and to visualize the keratocyte structures and collagen lamellas with submicron resolution. Multiphoton nonlinear imaging occurs only with high light intensity on an order of MG-GW/cm~2 and photon flux density of more than 10~(24) photons cm~(-2)s~(-1) in a 0.1 femtoliter intrastromal focus volume obtained by diffraction-limited focussing with high-numerical objectives. This technique, acting as a novel diagnostic tool, proved to be essential for femtosecond (fs) nanojoule (nJ) cornea surgery to determine the interest of region preoperation, to visualize and verify the outcomes immediately after the laser surgery and has potential to become a powerful tool in advancing understanding of corneal biomechnics and cellular reactions after laser induced lesion.