Photonic crystal

About: Photonic crystal is a research topic. Over the lifetime, 43424 publications have been published within this topic receiving 887083 citations.

Photonic crystal microcavities for cavity quantum electrodynamics with a single quantum dot

Abstract: We propose a planar photonic crystal microcavity design specially tailored for cavity quantum electrodynamics with a single quantum dot emitter embedded in semiconductor With quality factor up to 45 000, mode volume smaller than a cubic optical wavelength in material, and electric field maximum located in the high-refractive index region at the cavity center, this design can enable both strong coupling and lasing with a single quantum dot exciton The achievable range of the quality factor to mode volume ratios and the feasible fabrication of the proposed structure make it favorable to other semiconductor microcavities

High-Contrast Electro-Optic Modulation of a Photonic Crystal Nanocavity by Electrical Gating of Graphene

Abstract: We demonstrate a high-contrast electro-optic modulation of a photonic crystal nanocavity integrated with an electrically gated monolayer graphene. A high quality (Q) factor air-slot nanocavity design is employed for high overlap between the optical field and graphene sheet. Tuning of graphene's Fermi level up to 0.8 eV enables efficient control of its complex dielectric constant, which allows modulation of the cavity reflection in excess of 10 dB for a swing voltage of only 1.5 V. We also observe a controllable resonance wavelength shift close to 2 nm around a wavelength of 1570 nm and a Q factor modulation in excess of three. These observations allow cavity-enhanced measurements of the graphene complex dielectric constant under different chemical potentials, in agreement with a theoretical model of the graphene dielectric constant under gating. This graphene-based nanocavity modulation demonstrates the feasibility of high-contrast, low-power frequency-selective electro-optic nanocavity modulators in graphene-integrated silicon photonic chips.

A wavelength-selective photonic-crystal waveguide coupled to a nanowire light source

Abstract: The efficient delivery of photons from light sources to photonic circuits is central to any fibre-optic or integrated optical system. Coupling light emitters to optical fibres or waveguides determines the photon flux available in, and therefore the performance of, photonic devices used in applications such as optical communication and information processing. Many solutions have been proposed to improve impedance matching in light-emitting diode-to-fibre or photonic-crystal cavity-to-waveguide systems; however, the efficient coupling of integrated light sources into nanophotonic circuits remains a challenge. Here, we propose an optically or electrically driven photonic structure that uses active semiconductor nanowires to light up photonic-crystal waveguides. The photonic crystal is used to either guide or filter out different colours of light as desired. In addition, we report an active nanowire-based optical structure that can generate two different colours of light and then send them in opposite directions. The hybrid nanowire/photonic-crystal waveguide represents a significant advance towards all-optical processing in nanoscale integrated photonic circuits and a new addition to the nanophotonic toolbox.

Photonic crystal slab Laplace operator for image differentiation

Abstract: Spatial differentiation is important in image-processing applications such as image sharpening and edge-based segmentation. In these applications, of particular importance is the Laplacian, the simplest isotropic derivative operator in two dimensions. Spatial differentiation can be implemented electronically. However, in applications requiring real-time and high-throughput image differentiation, conventional digital computations become challenging. Optical analog computing may overcome this challenge by offering high-throughput low-energy-consumption operations using compact devices. However, previous works on spatial differentiation with nanophotonic structures are restricted to either one-dimensional differentiation or reflection mode, whereas operating in the transmission mode is important because it is directly compatible with standard image processing/recognition systems. Here, we show that the Laplacian can be implemented in the transmission mode by a photonic crystal slab device. We theoretically derive the criteria for realizing the Laplacian using the guided resonances in a photonic crystal slab. Guided by these criteria, we show that the Laplacian can be implemented using a carefully designed photonic crystal slab with a non-trivial isotropic band structure near the Γ point. Our work points to new opportunities in optical analog computing as provided by nanophotonic structures.

Optical Properties Of Low-Dimensional Materials

Abstract: Lattice dynamics in disordered systems probed through optical responses, Y. Kanemitsu Photoinduced phase transitions in low-dimensional semiconductors, S. Koshihara Excitons and nonlinear excitations in low-dimensional systems, K. Harigaya Spin-related optical phenomena in low-dimensional semiconductors, S. Takeyama radioactive recombination in strained SiGe/Si and allied group-IV semiconductor quantum structures, S. Fukatsu Ultrafast coherent dynamics in semiconductors, T. Mishina Optical properties of GaAs quantum wires, T. Sogawa Optical properties of semiconductor microcavities, Y. Kadoya Optical properties of photonic crystals, K. Sakoda.