超快、超解析度數位全像造影技術與應用之研究

This study presents the spatial and temporal imaging in digital holographic microscopy for high resolution quantitative analysis. Firstly, to enhance the spatial resolution in digital holographic microscopy, the normalization method is proposed and demonstrated in synthetic aperture digital holographic microscopy. The noise signal in low frequency will be stopped by apodization mask, thus the lateral resolution can be enhance to 200 nm and axial accuracy can be down to 1 nm. Then in order to avoid the mechanism scanning task for the synthetic aperture architecture, we propose the polarization and angle multiplexing technique to programmable scan the incident object beam by using the liquid crystal spatial light modulator. Moreover, the Moire effect is also employed in the synthetic aperture architecture. The additional high frequency information can be analysis in the Moire pattern, and the frequency coverage will be easier to increase to two times in lower numerical aperture microscopy system. Otherwise, the spiral phase digital holographic microscopy is also proposed and demonstrated in this project. Compare to convention interference technique in digital holographic microscopy, the common path architecture based on spiral phase modulation in object wave has a more stable recording process, which is more suitable for the applications in industry and research environment. For the enhancement in temporal resolution, the pulse laser is employed in the digital holographic microscopy to achieve the sub picosecond time resolution based on the pulse duration of the pulse laser. So, we propose and demonstrate a novel dual-wavelength pump-probe digital holographic microscopy to observe the ultrafast phenomenon of single pulse-induced phase change in low dispersion material. The ultrafast effect can be easily analyzed and determinate from the continues changes by a pulse train pumping. Also the time-resolved technique can be realized in digital holographic microscopy, and the pulse-induced phase variation in picosecond time scale can be observed according to the different time delay of the pumping beam. The ultrafast phenomenon of photoexcited phase change in dielectric material can thus be observed and analysis by pulsed digital holographic microscopy. Analytical and experimental results are presented and discussed.