Numerical design of photonic crystal optical tweezers for nanoparticles

This thesis is about optical tweezers for trapping cells and smaller sized biomaterials in a region using a focused laser beam using optical radiant forces. Tweezing often requires complex optics and alignment systems. In recent years, photonic crystals, which is a more practical approach, have also been used. The thesis covers numerical modeling of 2D dielectric photonic crystals, optimizing point and line defect frequencies and monitoring the motions of nanoparticles under the influence of electromagnetic field distributions to show that photonic crystal point and line defect states can be used in trapping or size separation of nanoparticles. Band structures for photonic crystals were obtained by Plane Wave Expansion and Finite Element Methods, respectively. The findings show that small volume, scalable and versatile optical tweezers that are easy to manufacture, do not require complex optical components and alignment assemblies can be realized in practice.