Abstract
Abstract: :
Purpose: All–solid–state ultrafast lasers are not only attractive for therapeutic applications in refractive surgery, keratoplasty and glaucoma treatment, but also promising for diagnostic purpose for non–invasive high resolution ocular tissue imaging. Multi–harmonic generation from corneal tissue and autofluorescence imaging of retinal tissue are of our main interests. Methods: Excised porcine eye samples were probed with a homemade Nd:glass femtosecond laser with regenerative amplifier and a commercial Ti:sapphire femtosecond laser. Cornea multi–harmonic imaging and retina two photon autofluorescence imaging were conducted with a ZEISS multiphoton laser scanning microscopy. Results: Femtosecond laser induced multi–harmonic generation enabled a diffraction limited high resolution corneal tissue imaging with strong contrast and large sensing depth. Staining or slicing was not required for sample preparation. Two–photon autofluorescence imaging of retinal tissue demonstrated high sensitivity with satisfactory resolution, which could be used as a complementary imaging mode for confocal retina tomography and optical coherent tomography. Conclusions: Based on the nonlinear phenomenon induced by the ultrafast laser pulse including multi–harmonic generation and two photon autofluorescence, ultrafast lasers may lead to new imaging methods for non–invasive ocular tissue diagnostics and in–vivo clinical study.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • laser • microscopy: light/fluorescence/immunohistochemistry