| dc.description.abstract | Optical microscopies have been applied widely for observations and measurements in fields of biology, materials, etc., mainly because of its non-invasive nature. However, the wave properties of light have limited the lateral resolutions of far-field optical microscopies to half of its excitation wavelength. Yet, as technology has greatly advanced, the expectations for the resolving power of optical microscopies have also grown a lot higher.
This article will introduce “Structured Illumination Microscopy (SIM),” a commonly applied far-field and super-resolution microscopy technique, and the principles of its image reconstruction.Since conventional structured illumination microscopies can only be used to observe samples with fluorescent properties, we’ve set up a coherent structured illumination microscopy system, and with the use of a phase-step algorithm, not only will the system’s resolution improve, it will also prevent photo bleaching in samples. In our system, a structured illumination pattern is produced by having two parallel lights interfere on the image plane, which is then used to excite the sample. And by obtaining the scattering images of different pattern directions and phases, we can solve the high frequency information. After setting up the system, we observed gold-nanoparticles, yet the resolution is enhanced only up to a factor of 1.2, which doesn’t match up with the theoretical value, 1.44. We will discuss the reasons of experimental errors later in this thesis.
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