| Summary: | 碩士 === 國立中正大學 === 物理所 === 95 === This thesis investigates image modulation of a transparent biological specimen using a phase contrast microscope with a DDLC (dye doped liquid crystal) film as the phase filter.
The phase contrast microscope was first proposed by Dutch physicist Frederik Zernike in 1953. It has an advantage, over the conventional ones, in that it can observe transparent living cells in their natural state. Primarily, it uses a phase plate to vary the phase of the surrounding wave by or but maintain the phase of the diffracted wave. Therefore, recombination of the surrounding and diffracted waves causes a phase contrast at the exit surface of the phase plate and makes the structural detail of a transparent specimen visible in the background of the biological image.
In our experiment, we use a DDLC film as a phase plate. Because it absorbs Argon+ laser at , it changes the phase of the surrounding wave by , by thermal nonlinear refraction, at an appropriate input power. This phase change is verified by an independent pump-probe technique.
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