Strong Coupling Between Photonic Cavities

Abstract

As the performance of computers has improved dramatically since the 1990s, many interesting photonic crystal properties have been theoretically and experimentally discovered. For example, the strong coupling between photonic crystal cavities was revealed in the 2000s; many groups have successfully fabricated these cavities and verified strong coupling experimentally using silicon. In this thesis, instead of using silicon, we present new results on photonic crystals made by thin indium tin oxide (ITO) layers. Compared to silicon, ITO is not an ideal material to make a photonic crystal because of its comparatively low refractive index and limited transparency. However, it is an interesting model material for experiments in photoemission electron microscopy (PEEM). ITO has a high conductivity that mitigates surface charge-up in an electron microscope and allows electron emission after 2-photon absorption with visible light. We are interested in PEEM because it enables the visualization of the propagation of light with nanometer resolution, i.e., below the optical diffraction limit. In this thesis, we theoretically study ITO photonic crystals in one or two-dimensions with the help of the finite-difference time-domain (FDTD) software. We analyze the electromagnetic field distribution in a manner that the field distributions can directly be compared to experimental PEEM results. We also simulate the strong coupling effect between neighboring cavities and illustrate it in terms of the classical oscillator model.