Photonic crystal

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

Fragility of photonic band gaps in inverse-opal photonic crystals

Abstract: Inverse-opal techniques provide a promising routine of fabricating photonic crystals with a full band gap in the visible and infrared regimes. Numerical simulations of band structures of such systems by means of a supercell technique demonstrate that this band gap is extremely fragile to the nonuniformity in crystals. In the presence of disorder such as variations in the radii of air spheres and their positions, the band gap reduces significantly, and closes at a fluctuation magnitude as small as under 2% of the lattice constant. This imposes a severe requirement on the uniformity of the crystal lattice. The fragility can be attributed to the creation of this band gap at high-frequency bands (eight to nine bands) in inverse-opal crystals.

Nanoparticle-tuned structural color from polymer opals

Abstract: The production of high-quality low-defect single-domain flexible polymer opals which possess fundamental photonic bandgaps tuneable across the visible and near-infrared regions is demonstrated in an industrially-scalable process. Incorporating sub-50nm nanoparticles into the interstices of the fcc lattice dramatically changes the perceived color without affecting the lattice quality. Contrary to iridescence based on Bragg diffraction, color generation arises through spectrally-resonant scattering inside the 3D photonic crystal. Viewing angles widen beyond 40 masculine removing the strong dependence of the perceived color on the position of light sources, greatly enhancing the color appearance. This opens up a range of decorative, sensing, security and photonic applications, and suggests an origin for structural colors in Nature.

Lithium niobate photonic-crystal electro-optic modulator

Abstract: Modern advanced photonic integrated circuits require dense integration of high-speed electro-optic functional elements on a compact chip that consumes only moderate power. Energy efficiency, operation speed, and device dimension are thus crucial metrics underlying almost all current developments of photonic signal processing units. Recently, thin-film lithium niobate (LN) emerges as a promising platform for photonic integrated circuits. Here, we make an important step towards miniaturizing functional components on this platform, reporting high-speed LN electro-optic modulators, based upon photonic crystal nanobeam resonators. The devices exhibit a significant tuning efficiency up to 1.98 GHz V-1, a broad modulation bandwidth of 17.5 GHz, while with a tiny electro-optic modal volume of only 0.58 μm3. The modulators enable efficient electro-optic driving of high-Q photonic cavity modes in both adiabatic and non-adiabatic regimes, and allow us to achieve electro-optic switching at 11 Gb s-1 with a bit-switching energy as low as 22 fJ. The demonstration of energy efficient and high-speed electro-optic modulation at the wavelength scale paves a crucial foundation for realizing large-scale LN photonic integrated circuits that are of immense importance for broad applications in data communication, microwave photonics, and quantum photonics.

Bioinspired Water‐Vapor‐Responsive Organic/Inorganic Hybrid One‐Dimensional Photonic Crystals with Tunable Full‐Color Stop Band

Abstract: Bioinspired organic/inorganic hybrid one-dimensional photonic crystals (1DPCs) are prepared by alternating thin films of titania and poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (PHEMA-co-PGMA) by spin-coating, which is a simple, reproducible, and low-cost approach. Their optical properties are tuned by changing the number of layers, incident angles, and the thickness of the layers. The color of the 1 DPCs can span the entire visible spectral range when the period or the refractive index is changed. Due to the response of PHEMA-co-PGMA to water vapor, the 1 DPCs possess fast water-vapor responsiveness and reversible full-color switching. The color of the 1 DPCs varies from blue to green, yellow, orange, and red under differing humidities, covering the whole visible range. At high water-vapor concentrations, the color of the 1 DPCs rapidly changes from blue to red and comes back to the original state immediately after exposure to air; this behaviour is like that of some animals in nature. The repeatability of the reversible response of the 1 DPCs to water vapor is perfect and can be repeated more than 100 times. The as-prepared 1DPCs successfully combine structural color and water-vapor sensitivity, which is promising for use as materials for colorful detection across the full color range.

Photonic Crystals: Physics and Practical Modeling

Abstract: to Photonic Crystals.- Fundamentals of Wave Optics.- Fundamentals of Computation of Photonic Crystal Characteristics.- Band Structure Computation of 1D Photonic Crystals.- Band Structure Computation of 2D and 3D Photonic Crystals.- Finite-Difference Time-Domain Method for PhC Devices Modeling.- Photonic Crystal Optical Fibers.- FDTD Method for Band Structure Computation.- Photonic Crystal Waveguides.- Application for Design and Simulation of Optical WDM Demultiplexer.