Fiber-optic endomicroscopy for intrinsic nonlinear optical imaging of biological tissues
Event details
| Date | 21.05.2010 |
| Hour | 13:30 |
| Speaker | Yicong Wu, Department of Biomedical Engineering, Johns Hopkins University |
| Location | |
| Category | Conferences - Seminars |
In this talk, I will report on a fiber-optic scanning endomicroscopy technology that enables intrinsic two-photon fluorescence (TPF) and second harmonic generation (SHG) imaging of biological tissues. There are many challenges in developing such a technology, including single-mode delivery of fs excitation pulses, efficient collection of the nonlinear optical signals, an ultra-compact scanner for fast beam scanning, and high-quality miniature optics to handle the large separation between the excitation and TPF/SHG wavelengths. In our endomicroscope, a double-clad fiber (DCF) was employed for single-mode fs pulse delivery and multimode TPF/SHG collection. The DCF also served as resonant cantilever driven by a PZT actuator for fast 2D beam scanning. A miniature compound lens was developed to achieve a tight excitation focus, reduce chromatic aberration and improve TPF/SHG collection. In addition, a short multimode fiber was introduced at the tip of the DCF to further mitigate the adverse effect of chromatic aberration. TPF/SHG imaging of fluorescent beads demonstrated ~9 times improvement on TPF/SHG collection with the new design over a conventional GRIN lens based endomicroscope. Recently we have developed a customized DCF of a larger inner-clad diameter to effectively suppress the background TPF/SHG signal and improve the TPF/SHG collection efficiency, thus greatly improving the signal-to-background ratio by a factor ~100. These technological innovations have made possible to perform real-time two-photon autofluorescence imaging and second harmonic generation of biological tissues for the first time with a fiber-optic endomicroscope. Our results show strong promise of the fiber-optic endomicroscopy technology for translating TPF/SHG microscopy to in vivo and clinical applications.
Practical information
- General public
- Free