Nanoscale experimental and numerical investigations of novel photonic devices

Abstract

For many centuries, physicists and engineers have explored the creation, manipulation and detection of light. Only within the past century, however, have fabrication techniques advanced to the point where individual photons can be generated, manipulated, and measured. These advances have brought us to the point we are at today, where photonic devices are set to revolutionize the fields of computing, sensing and quantum information, to name a few. Despite the promise of these devices, scientists are still working to fully understand the light-matter interactions that govern their behavior. In this thesis, we uniquely characterize the behavior of certain photonic devices in an effort to understand the underlying physical principles that define them. Of particular interest to us is imaging via near-field scanning optical microscopy (NSOM) of photonic integrated circuit (PIC) elements with high quality factors (Q), such as microring resonators and photonic crystal cavities (PhCs). While these elements are becoming ubiquitous in emerging PIC designs, they have remained difficult to accurately image due to their high sensitivity to small perturbations (i.e. the NSOM probe). We solve this problem by controllably modulating the NSOM tip-sample distance and reducing the size of the probe. Finite element model computer simulations demonstrate that both of these adjustments decrease the tip sample interaction. We then apply this knowledge to generate first of their kind 50 nm resolution NSOM images of high Q resonant PIC devices. Importantly, aside from being accurate, the proposed NSOM technique is also facile and non-destructive. In addition to local field exploration of PIC elements, we explore non-classical optical transmission through sub-wavelength apertures in metallic films. We demonstrate that these interesting features arise from photonic wave interference.