ABSTRACT
We optimize photonic crystal cavities for enhancing the sensitivity to environmental changes by finite-difference time-domain method. For the heterostructure cavity created by local modulation of the air hole radius, the resonance shifts due to refractive index change of the background material are investigated. The shifts can be enhanced by reducing the photonic crystal slab thickness or introducing air holes in the cavity. The sensitivity of the thinner slab with central air holes is 310 nm/RIU (refractive index unit). The heterostructure created in the slotted waveguide of thin PhC slab shows better sensitivity of 512 nm/RIU owing to strong confinement of electric field in the low-index region.
Subject(s)
Biopolymers/analysis , Biosensing Techniques/instrumentation , Microfluidics/instrumentation , Nanotechnology/instrumentation , Optics and Photonics/instrumentation , Refractometry/instrumentation , Biosensing Techniques/methods , Equipment Design , Equipment Failure Analysis , Microfluidics/methods , Photons , Refractometry/methods , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
We present a scalable method for the fabrication of site-controlled quantum dots (QDs) embedded in optical resonators. The position of the quantum dots is determined by nucleating their growth in an array of nano-holes that is aligned to a set of markers, allowing the precise overlay of the resonator geometry over the QD array. Coupling of the QDs to the resonators is demonstrated by the resonant enhancement of the spontaneous emission observed in photoluminescence experiments.
ABSTRACT
We propose an ultrahigh quality factor (Q) photonic crystal slab cavity created by the local modulation of the air hole radius in the waveguide. In the cavity, photons are confined between two mirror regions with larger air holes and the lifetime of photons is greatly enhanced by introducing tapered regions with linearly increasing air hole radii. Q and mode volume are investigated for the cavities with various lengths and air hole size offsets of the tapered region with linearly increasing air hole radii by three-dimensional finite-difference time-domain method. The behaviors are analyzed by the mode patterns in real space and wavevector space. We obtain a numerical Q up to 8.8 x 10(7) for a mode volume of 1.6 (lambda/n)(3). Concerning the waveguide coupling, the cavity shows 80% coupling efficiency while keeping Q higher than 10(6).
Subject(s)
Computer-Aided Design , Crystallization/methods , Models, Theoretical , Nanotechnology/instrumentation , Optics and Photonics/instrumentation , Transducers , Air , Computer Simulation , Equipment Design , Equipment Failure Analysis , Nanotechnology/methods , PhotonsABSTRACT
Membrane-based photonic crystal GaAs cavities with a double-heterostructure design were investigated. They show the highest quality factors for GaAs photonic crystal cavities to date, exhibiting quality factors higher than 10(5). The resonances of these cavities were fine-tuned in steps smaller than 2 nm by digital etching.
