Design and Analysis of High Performance Photonic Crystal Nanocavity

Abstract

Photonic Crystal Nanocavit ies are gett ing significant attent ion because of their potent ial of trapping and storing photons in a small region of nanometer range and enhancing light interaction with various funct ional materials and structures. A strong light-matter interaction is obtained in high quality photonic crystal nanocavit ies that strongly confine photons in a small cavity region of opt ical wavelength dimension. Because of their capability to confine and manipulate photons in nanometer scales, high-Q PhC nanocavit ies find applicat ions in various fields, such as photonics, telecommunicat ions, quantum informat ion and cavity quantum electrodynamics. The present work aims at designing, simulat ion and analysis of a L3 photonic crystal nanocavity. This work is directed towards designing a cavity structure which has a single mode with ultra-high Q-factor and small mode volume, confined in the cavity. A high Q-factor and small mode volume gives a large Q/V and enhances the Purcell factor. The opt imizat ion is done in order to get better temporal and spat ial confinement of the confined resonant mode in the nanocavity. The research work is performed on a thin photonic crystal slab made out of gallium arsenide with a triangular array of air holes. L3 type defect is created in the crystal with three missing air-holes in the center of the slab. The cavity structure is designed by shift ing four nearest neighbour air-holes on cavity edges and shrinking first nearest neighbour air - holes. By fine-tuning the four nearest neighbour air-holes on cavity edges, the electric field profile can be tailored. As a result, we have obtained a single cavity mode at resonant frequency 0.258 c/a with Q-factor 493681, mode volume 0.828 and Q/ of 615152 . This design improves the quality factor by a factor of 84 and Q/ by a factor of 70 in comparison to unopt imised L3 photonic crystal nanocavity. Such photonic crystal nanocavit ies lead to very large Purcell factor because of their ultra-high Q-factor and ultra-small cavity mode volume. They can be used for realizat ion of quantum comput ing platform by coupling with quantum dots and nanocavity lasers.