Nanophotonic Devices Based on Planar Photonic Crystals

Citation

Lončar, Marko (2003) Nanophotonic Devices Based on Planar Photonic Crystals. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/SB3Y-8Z20. https://resolver.caltech.edu/CaltechETD:etd-06022003-042444

Abstract

Photonic Crystals, man-made periodic structures with a high refractive index contrast modulation, have recently become very interesting platform for the manipulation of light. The existence of a photonic bandgap, a frequency range in which propagation of light is prevented in all directions, makes photonic crystals very useful in applications where spatial localization of light is required. Ideally, by making a three-dimensional photonic crystal, propagation of light in all three dimensions can be controlled. Since fabrication of 3-D structures is still a difficult process, a more appealing approach is based on the use of lower dimensional photonic crystals. A concept that has recently attracted a lot of attention is a planar photonic crystal based on a dielectric membrane, suspended in the air, and perforated with a two-dimensional lattice of holes.

In this thesis theoretical and experimental study of planar photonic crystal nanolasers, waveguides and super-dispersive elements is presented. Room temperature operation of low-threshold nanolaser is demonstrated, both in air and in different chemical solutions. For the first time, we have demonstrated that photonic crystal nanocavity lasers can be used to perform spectroscopic tests on ultra-small volumes of analyte. Our porous cavity design permits the introduction of analyte directly into the high optical field of the laser cavity, and therefore it is ideally suited for the investigation of interaction between light and matter on a nanoscale level. We showed that small changes in refractive index of the ambient surrounding the laser can be detected by observing the shifts in emission wavelengths of the laser. Our lasers can be integrated into large arrays to permit the analysis of many reagents at the same time. The nanolasers can also be integrated with photonic crystal waveguides to form the integrated systems of higher complexities. Theoretical and experimental investigation of various photonic crystal waveguide designs is discussed. Details of the fabrication procedure used to realize nanophotonic devices in silicon on insulator as well as InGaAsP materials are presented.

Thesis Files