The Applications Of Two Novel Optical Materials To The Biological Microscopy And Spectroscopy

Motivated by a rapid evolution of nanotechnology and fabrication in the past decades, nanomaterials have successively found their place in the applications in our production and daily life. Meantime, exploiting of novel nanomaterials is becoming a hot topic in optics, material and biology research. This thesis focuses on two kinds of novel optical materials. Their optical properties and their applications in optics area are discussed in detail. The relevant research work is as follows.We introduce a new series of fluorescent materials with aggregation induced emission (AIE) property. Both their optical properties and the potential application are studied.We first describe the absorption and emission properties of TPE-TPA-FN and HPS, both AIE compounds. After encapsulated into nanomicelles, TPE-TPA-FN nanoparticles are injected into HeLa cells as fluorescent probe, and used for in vitro bio-imaging in a homemade confocal-nondescanned bio-modal microscope. We then compare the photobleaching resistance and the stimulated emission depletion (STED) efficiency between HPS and Coumarin, a kind of common dyes. The result shows HPS is much more resistant to photobleaching than Coumarin under a high power exposure, more photo-stable in long-term imaging, and also with higher depletion efficiency, all of which implies a great potencial of AIE materials if applied in STED superresolution bioimaging.We study the nonlinear optical properties of a kind of nano-structured alkaline niobate—— potassium niobate nanoneedle, and its two applications based on these properties.We characterize the harmonic generation of potassium niobate nanoneedle. Using femtosecond pulse laser and multiphoton microscope, we examine polarization-dependent properties of second harmonic generation (SHG) and third harmonic generation (THG) emitted from individual nanoneedle; Using wavelength tunable pulse laser, we measure the wavelength-dependent SHG and THG efficiency of the nanoneedles. Based on the high SHG efficiency, we arise a new method, with nanoneedles as nonlinear probe, of more accurately evaluating the best excitation wavelength for nonlinear optical deep imaging. We also varify the advantage of the third optical window in deep bioimaging.Besides, the sum frequency generation (SFG) of potassium niobate nanoneedle is also measured with a picosecond pulse laser from a fiber laser and a supercontinuum pulse laser from a ps-laser-pumped photonic crystal fiber. We further apply the SHG and SFG properties in pulse laser characterization. The ps pulse is first measured by a homemade auto-correlator with the nanoneedles as nonlinear material, phase information is attained from the calculation afterwards. The measurement of supercontinuum pulse is performed on a pump-probe system based on the cross-correlation frequency-resolved optical gating. With nonneedles as the SFG crystal, the information of supercontinuum pulse can be obtained in both time and frequency domains.