Spherical Photonic Crystals Research Articles

Multi-physical quantity sensing based on magnetized plasma spherical photonic crystals with evanescent wave

In this paper, a novel structure of magnetized plasma spherical photonic crystals is proposed that enables the development of sensors based on the evanescent wave principle. This sensor structure integrates plasma with two isotropic media and applies periodic boundary conditions. Leveraging the principle of the evanescent wave, when the incident light is perpendicular to the interface of a medium with high optical density or thickness and the incident angle exceeds a critical angle, the transfer matrix method is utilized to compute the sharp peaks in the transmission spectrum. Subsequently, sensors produced using these sharp absorption peaks can detect the magnetic induction intensity, plasma frequency, and solution concentration of serum creatinine. The sensitivity and quality factors of these measurements are 8.35 × 1010 T−1, 3583, 1.5 × 10−4 (2πc/d)−1, 2970, 3.55, and 22 824, respectively. Furthermore, a detection limit of 9.155 02 × 10−6 RIU should be taken into account to ensure the normal operation of serum creatinine detection, satisfying the minimum requirements of biosensing.

The absorption properties of one-dimensional spherical photonic crystals based on plasma material

The first theoretical treatment of the electromagnetic properties of one-dimensional plasma spherical photonic crystals (1D PSPCs) in the non-magnetized state is carried out to obtain the expressions for the electric and magnetic fields. The utilization of the transfer matrix method provides a new idea for the exploration of the 1D PSPCs, based on which the expressions for the absorptance of the 1D PSPCs are derived. A structure of quasi-periodic 1D PSPCs arranged according to the Thue-Morse sequence is proposed to acquire the ultra-wide absorption bands (ABs) at large incidence angles by adding an air layer and setting the plasma frequency in a gradient. And the factors affecting the ABs are meticulously analyzed. It is figured out that the primary factors affecting ABs are topology and plasma frequency, both of which have vigoroso influences on the bandwidths and positions of ABs. However, the initial radius and the collision frequency prevailingly affect the amplitude of the absorptance. The unexceptionable geometric properties of the 1D PSPCs make them sensitive to parameter changes and can be applied in the field of absorbers and radomes, which have great application prospects and development space.

(Ann. Phys. 2/2023)

Annalen der PhysikVolume 535, Issue 2 2370003 Cover PictureFree Access (Ann. Phys. 2/2023) First published: 16 February 2023 https://doi.org/10.1002/andp.202370003AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Spherical Photonic Crystals In article number 2200370, Hai-Feng Zhang and co-workers conduct a theoretical analysis of the transmission characteristics of 1D magnetized ferrite spherical photonic crystals (SPCs). The SPC structure is constructed for the application of magnetized ferrite. Volume535, Issue2February 20232370003 RelatedInformation

Investigation of photonic band gap properties of one-dimensional magnetized plasma spherical photonic crystals

Utilizing the transfer matrix method (TMM), the magnetic and electric field equations of Maxwell’s system of equations in the spherical coordinate system are constructed. By combining the solution of the spherical Bessel equation to theoretically treat the magnetic and electric fields of a one-dimensional (1-D) magnetized plasma spherical photonic crystals (MPSPCs), detailed expressions for the transmission properties and dispersion relations of 1-D MPSPCs are obtained. The structure of 1-D MPSPCs is also designed, and the effects of the cyclotron frequency of plasma, incidence angle, collision frequency, plasma frequency, structure, dissipation factor and plasma thickness on the photonic band gaps (PBGs) features are discussed. With the adjustment of these parameters, the impact of the collision frequency on the transmission properties is extraordinarily insignificant. The plasma frequency and the cyclotron frequency of plasma have quite similar effects on the PBGs. The variation of incidence angle and plasma frequency thickness affects not only the position of PBGs but also the amount of them. The difference in structure and the change in dissipation factor have no effect on the distribution of PBGs and only a slight effect on the amplitude of the transmission spectra.

The Absorption Properties of One‐Dimensional Spherical Photonic Crystals Based on Magnetized Ferrite Materials

AbstractBased on a spherical coordinate system and Maxwell's set of equations, the calculation formulas of one‐dimensional (1‐D) magnetized ferrite spherical photonic crystals (MFSPCs) are obtained and treated with the solution method of the spherical Bessel equations. Combined with the conventional transmission matrix method, expressions for the absorptance, reflectance, and transmittance of the 1‐D MFSPCs are given. 1‐D MFSPCs consisting of the general dielectric and Yttrium iron garnet (YIG) are also designed to verify the correctness of the conclusions. Variables such as external magnetic field, incidence angle, initial radius, and YIG thickness effects on the features of such 1‐D MFSPCs are also discussed. The transformation of the external magnetic field has a linear relationship with the position of the absorption band (AB). The three variables of incidence angle, initial radius, and YIG thickness have a substantial influence on the width and position of the AB, which can be adjusted according to the actual demand and are of high application significance. The results of this study can be helpful for the design of multifunctional absorbers and radome.

Highly Selective Photocatalytic Conversion of Glucose on Holo-Symmetrically Spherical Three-Dimensionally Ordered Macroporous Heterojunction Photonic Crystal

Highly Selective Photocatalytic Conversion of Glucose on Holo-Symmetrically Spherical Three-Dimensionally Ordered Macroporous Heterojunction Photonic Crystal

Modular Assembly of Mechanoresponsive Color‐Changing Materials from Hydrogel‐Based Photonic Crystal Microspheres

Mechanoresponsive, soft, photonic materials with tunable structural coloration represent a class of materials that have potential benefits for a wide range of applications. While many lab‐scale fabrication approaches afford control over the nano‐ and microscale morphology of these materials, upscaling their manufacture remains a challenge. Herein, a scalable fabrication concept is proposed that centers on the modular assembly of color‐changing materials from microscale building blocks. The building blocks consist of hydrogel‐based spherical photonic crystals. They are formed through a water‐in‐oil emulsification of nanoscale colloidal particles suspended in the aqueous phase. Once formed, the photonic crystal microspheres are then assembled into macroscale photonic materials, such as stretchable fibers or sheets. The resulting materials respond to a mechanical deformation with a reversible, dynamic change in color. Fabricated via a scalable, modular‐assembly approach, these mechanoresponsive photonic fibers and sheets, in turn, form a valuable building block for sensing systems or visual communication in healthcare, architecture, and consumer product design.

Mass Transport Determined Silica Nanowires Growth on Spherical Photonic Crystals with Nanostructure-Enabled Functionalities.

A robust and facile method has been developed to obtain directional growth of silica nanowires (SiO2 NWs) by regulating mass transport of silicon monoxide (SiO) vapor. SiO2 NWs are grown by vapor-liquid-solid (VLS) process on a surface of gold-covered spherical photonic crystals (SPCs) annealed at high temperature in an inert gas atmosphere in the vicinity of a SiO source. The SPCs are prepared from droplet confined colloidal self-assembly. SiO2 NW morphology is governed by diffusion-reaction process of SiO vapor, whereby directional growth of SiO2 NWs toward the low SiO concentration is obtained at locations with a high SiO concentration gradient, while random growth is observed at locations with a low SiO concentration gradient. Growth of NWs parallel to the supporting substrate surface is of great importance for various applications, and this is the first demonstration of surface-parallel growth by controlling mass transport. This controllable NW morphology enables production of SPCs covered with a large number of NWs, showing multilevel micro-nano feature and high specific surface area for potential applications in superwetting surfaces, oil/water separation, microreactors, and scaffolds. In addition, the controllable photonic stop band properties of this hybrid structure of SPCs enable the potential applications in photocatalysis, sensing, and light harvesting.

Multilevel Spherical Photonic Crystals with Controllable Structures and Structure‐Enhanced Functionalities

AbstractSpherical photonic crystals (SPCs) with tailorable multiscale structure, versatile surface morphology, and controllable optical properties of both photonic stop band (PSB) and surface plasmon resonance (SPR), have been fabricated using a robust and facile method. The fabricated SPCs consist of well‐spaced gold nanocrystals (AuNCs) (3rd‐tier) anchored on silica nanopatterns (2nd‐tier) confined in microspherical templates (1st‐tier). Droplet microfluidics is used to produce microdroplets containing silica nanoparticles (SiO2NPs) which assemble to form two‐tier SPCs. Subsequently, three‐tier SPCs are obtained by thermal dewetting and evaporation of metal films deposited on the two‐tier SPCs, with the 3rd‐tier morphology being controlled by the deposited film morphology and programmed thermal annealing. Optical PSB and SPR properties of the prepared SPCs can be on‐demand tailored by the 2nd and 3rd‐tier morphology and their corresponding constituent materials. It is found that the scattering from AuNC arrays on the SPCs can be amplified by tailoring the PSB properties. The hierarchical SPCs manufactured by this method take advantages of low‐cost, high controllability, and further processability. The manufacturing of flexible film encapsulated well‐assembled SPCs as anticounterfeiting stamps, which are easy to be identified using the mobile phone with a flash, is demonstrated.

Ensembles of Photonic Beads: Optical Properties and Enhanced Light—Matter Interactions

AbstractLight management is of paramount importance to improve the performance of optoelectronic devices including photodetectors, optical sensors, solar cells, and light‐emitting diodes. Photonic crystals are shown as an effective metamaterial for trapping light among their various photon management functions. Herewith, it is demonstrated that spherical photonic crystals, or in other words, photonic beads, possess a stronger light‐trapping effect compared to the planar counterpart. The photonic beads are fabricated by colloidal self‐assembly under microdroplet confinement employing microfluidic devices. The light–matter interactions are illustrated by the emission intensity and lifetime of the embedded emitters, namely carbon dots and upconversion nanoparticles (UCNPs). The bandgaps of the photonic beads are selected according to the emission and excitation peaks of the light emitters, whereby the emission or excitation peak overlaps the blue edge or red edge of the photonic bands, respectively. Significantly stronger emission and extended luminescence lifetime are observed in photonic beads ensemble in comparison to the planar photonic crystals, demonstrating enhanced light trapping owing to the spherical geometry, which introduces additional microcavity effect. Photonic beads represent a perfect hierarchical light manipulation system. Combining both photonic and microcavity resonator effects, photonic beads potentially find applications in light harvesting, sensing, lighting devices, and light‐triggered manipulations.

Facile fabrication of spherical photonic crystals microspheres with angle-independent fluorescent functionality

In this work, we report a facile way to fabricate fluorescent spherical photonic crystals (SPCs) microspheres for the first time. The SPCs microspheres immobilizing Photonic Bandgap (PBG) structure into a hydrogel framework, which can be used to uptake nanosized CdTe NCs particles based on their reversible volume phase transition behavior. Moreover, the resultant SPCs microspheres can not only monitor surrounding humidity, but also exhibit well integration of fluorescence and PBG color in a single structure. More interestingly, the photoluminescence (PL) spectra of fluorescent SPCs microspheres are angle-independent on the curved surface which would open a novel insight into the fabrication of multifunctional optical devices based on PBG and PL functionalities.

Responsive Block Copolymer Photonic Microspheres.

Responsive photonic crystals (PCs) have attracted much attention due to their broad applications in the field of chemical and physical sensing through varying optical properties when exposed to external stimuli. In particular, assembly of block copolymers (BCPs) has proven to be a robust platform for constructing PCs in the form of films or bulk. Here, the generation of BCPs photonic microspheres is presented with 3D periodical concentric lamellar structures through confined self-assembly. The structural color of the spherical PCs can be tuned by selective swelling of one block, yielding large change of optical property through varying both layer thickness and refraction index of the domains. The as-formed spherical PCs demonstrate large reflection wavelength shift (≈400-700 nm) under organic solvent permeation and pH adjustment. Spherical shape and structural symmetry endow the formed spherical PCs with rotation independence and monochrome, which is potentially useful in the fields of displays, sensing, and diagnostics.

Tuneable multicoloured patterns from photonic cross-communication between cholesteric liquid crystal droplets

Cholesteric liquid crystal droplets are self-assembled spherical photonic crystals. Multiple droplets in the same plane communicate optically, giving rise to unique patterns of circularly polarised and strongly coloured spots. We explain the phenomenon and outline routes to application.

Achieving Complete Bandgaps by Self-Similar Spherical Structure Using Low Refractive Index Materials

A three-dimensional complete bandgap (CBG) in the visible range is achieved by a self-similar spherical photonic crystal (PC) fabricated using the materials with low refractive index. A novel holographic technique is developed to fabricate such a structure. A CBG with a width of 120 nm is obtained experimentally. Even though the light not passing through the center of the sphere incidents on the PC with an incident angle of 49, a 30-nm-wide CBG can still be kept. Theoretical analysis is also given in which experimental results can be well explained.

A comparison between unidimensional, circular and spherical photonic crystal stacks

One dimensional (1D), circular (2D) and spherical (3D) stacks have occupied quite an important place in Optics, Electronics and Solid State Physics on their own, that keeps growing with the development of Photonics. In particular Bragg and Photonic structures have found an application as Bragg fibers, microresonator, quantum dots like and many others structures; everything made feasible by the modern nanofabrication and others fabrication techniques. Their structural complexity still relies heavily on numerical simulation, with the exception of a few accessible cases. Among them, we study the scaling of a Bragg resonance (1/4 λ) stack from one-dimensional to circular and spherical structures, from the point of view of their photonic band gap. The similitude with the well known linear multilayer method is discussed.