Research On Key Techniques In Biomedical Optical Imaging

With rapid development in recent years, biomedical optical imaging, as a non-invasive, non-destructive and high resolution imaging technique, has become a focus of study in the fields of life science and optics. In this dissertation work, several key techniques of biomedical optical imaging was investigated by using a theoretical analysis-simulation-experiment-application research method. The adaptive phase compensation ultrashort pulse two-photon microscopy and the common-path Fourier domain optical coherence tomography (OCT) were studied, providing the solution for limited used in tissue imaging, endoscopy, surgical procedure guidance imaging and so on.Firstly, starting from the non-linear optics, the theory and advantages of two-photon microscopy were introduced. By describing the adaptive phase compensation (both low and high order dispersion are compensated) ultroshort pulse (10 fs) two-photon microscopy system in detail, the advantages of using ultroshort pulse after compensation were revealed. For the first time, the high order dispersion in two-photon microscopy was derivated theoretically and analyzed quantitatively. By studying the dispersion of optical materials and prism pairs in two-photon microscopy system, we found the origin of high order dispersion of the entire system. We discussed the advantages and disadvantages of long and short pulses in two-photon microscopy system, and showed that without adaptive phase compensation, the efficiency and excitation intensity of ultrashort pulses were even worse than long pulses for biomedical imging,Secondly, starting from the theory of optical tomography, the principle and characters of Fourier domain OCT were introduced. The common path OCT system were described in detail. For the first time, we suggested and analysed three different focus systems for fiber bundle endoscopic probe of common path OCT system. Signal to noise ratio was analyzed to optimize the probe configuration. Moreover, a surface topology and motion compensation system was developed first time for OCT and can be used for various clinical applications.In conclusion, we studied several key techniques of biomedical optical imaging, providing the better and wider applications in various fields, such as tissue imaging, endoscopy and surgical procedure guidance imaging.