Quasiperiodic Photonic Crystals Research Articles

Gamma radiation detector using Cantor quasi-periodic photonic crystal based on porous silicon doped with polymer

The measurement of patients’ dosages of radiation caused by medical diagnostics continues to be challenging. A Cantor sequence photonic crystal structure using porous silicon doped with a polymer of polyvinyl alcohol, carbol fuchsin and crystal violet (DPV) is proposed. The influence rules of geometrical and optical parameters such as the radiation doses, number of periods, porosity of porous layers, incident angle and thickness of layers are investigated using MATLAB based on the transfer matrix method. The transmittance of the Cantor sequence of a defective photonic crystal sensor under different conditions is investigated to select the optimum conditions. The proposed system recorded the accepted sensitivity of 0.265[Formula: see text]nm/Gy, FoM of 6.5[Formula: see text]Gy[Formula: see text], Q of 12,701, RS of [Formula: see text] and LoD of [Formula: see text] for gamma radiation. The suggested detector has simple design, accurate monitoring efficiency and immense potential for gamma radiation sensing.

Coupling between atoms and localized modes in a defect-free quasiperiodic photonic crystal

In this study, the evolution spectrum and emission dynamics of atoms in a defect-free quasiperiodic photonic crystal are studied. Quasiperiodic photonic crystal have advantages over periodic photonic crystal in terms of abundant and strong localized modes due to the quasiperiodic and self-approximation structures of quasiperiodic photonic crystal. The localized modes exhibit extremely large local density of states and high-quality factors in the quasiperiodic photonic crystal. The frequencies of the large local density of states of the localized modes do not depend on the polarization and the position in a particular area in the quasiperiodic photonic crystals. Due to the extremely large local density of states in the defect-free quasiperiodic photonic crystal, strong coupling between the atom and the localized mode in the quasiperiodic photonic crystal can easily occur. Correspondingly, the population of the excited state displays Rabi oscillation, and the emission spectrum of the atom splits into two peaks. Moreover, the Rabi oscillation and the evolution spectrum of the dressed atom depend on the radiation linewidth.

High-sensitivity refractive index sensor based on defective modes of an 8-fold quasi-periodic photonic crystal

The refractive index sensing performance of the 8-fold quasi-periodic photonic crystal (QPhC) defect modes is studied. The proposed QPhC structure consists of the silicon columns immersed in a free-flowing liquid environment to enable real-time detection. The refractive index sensitivity of 982 nm/RIU, and a detection limit of 4.82×10−5 are achieved at the near-infrared wavelength. The influence of protein's thickness attached by the central dielectric column on the resonant wavelength is investigated. For the optimized radius of the central column r = 375 nm, the Q value of the resonant peak exceeds 4.9×104, and a slight variation of protein's thickness less than 1 nm attached by the micro-cavity can be distinguished. The spatial field distributions of the multiple defect modes and the corresponding sensitivity are analyzed and explained.

Localized Modes and Photonic Band Gap Sensitivities with 1D Fibonacci Quasi-Crystals Filled with Sinusoidal Modulated Plasma

Using the transfer matrix method, the electromagnetic responses of 1D deformed and non-deformed quasi-periodic photonic crystals arranged in accordance with the Fibonacci sequence are theoretically studied. The gallium selenide (GeSe) and plasma materials (that is, electron density) are used to construct the multilayer Fibonacci structures. If this study is experimentally validated in the future, we intend to insert two transparent polymer film materials at the top and bottom of the structure, which are intended to protect the plasma material and prevent it from escaping and spreading outside the structure. The effect of the order of the Fibonacci sequence, the deformation of the thickness of the layers using a mathematical rule and the role of the plasma material in the reflectance response are discussed. We notice that the position and the width of photonic band gaps are sensitive to the Fibonacci sequence, the thickness and the density of the plasma material layers. In addition, the intensity of the resonance peaks can be controlled by adjusting the plasma material properties. The width of the photonic band gaps can be notably enlarged by applying a structural deformation along the stacks. The proposed structures have potential applications in tunable filters, micro-cavities for LASER equipment, which allow us to obtain an intense laser, and they are very useful in the communication field.

Enhanced Goos-Hänchen shift in a defective Pell quasiperiodic photonic crystal with monolayer MoS2.

Monolayer M o S 2 has attracted wide attention because of its finite bandgap, and it has become a potential candidate for the investigation of the Goos-Hänchen (GH) shift. However, the magnitude of the GH shift in free-standing monolayer M o S 2 is small, which greatly hinders its possible applications in the photoelectric sensors and detectors. We have theoretically designed a defective quasiperiodic photonic crystal and investigated its GH shift, where monolayer M o S 2 is sandwiched between two quasiperiodic photonic crystals arranged by the Pell sequence. By optimizing the thicknesses of all the components and the period number of the Pell quasiperiodic photonic crystal, we find that the GH shift of the designed structure is significantly enhanced at the specific working wavelength. In addition, we discuss the influence of the thicknesses of the dielectric components on the GH shift. Our work confirms that the quasiperiodic photonic crystal structure has the ability to enhance the GH shift of monolayer transition metal dichalcogenides, which provides a new platform for the GH investigations and greatly promotes the applications of this defective structure in optoelectric devices.

From fiber Bragg gratings to coaxial cable Bragg gratings: One-dimensional microwave quasi-periodic photonic crystals

Coaxial cables and optical fibers are two types of cylindrical waveguides used in telecommunications. Fiber Bragg gratings (FBGs) have found successful applications in various fields, such as optical communications, fiber lasers, and fiber-optic sensing. In this paper, we propose and numerically investigate the implementations of various fiber Bragg configurations, including uniform, chirped, apodized, and phase-shifted configurations, on coaxial cables to generate the corresponding special types of coaxial cable Bragg gratings (CCBGs). The simulation results of different CCBGs match well with the well-known FBG theories. It is demonstrated that the reflection spectrum of a CCBG can be flexibly tailored by introducing various quasi-periodic perturbations in the permittivity of the dielectric layer along the coaxial cable. The proposed special types of CCBGs with unique characteristics could find potential applications in radio frequency signal processing, communication, and sensing fields.

Transmission properties in Fibonacci quasi-periodic photonic crystal containing negative-zero-positive index metamaterials

The transmission properties in Fibonacci quasi-periodic photonic crystals containing negative-zero-positive index metamaterials (NZPIM) are investigated systematically. Because of linear dispersion, an asymmetric band gap appears near the optical Dirac point (DP) only at an oblique incidence. Zero- gaps and Bragg gaps exist when the refractive indexes of NZPIM are negative and positive, respectively. We also obtain gaps induced by total reflection on both sides of the DP gap. The corresponding Goos-Hänchen (GH) shifts and phase variations are also demonstrated in detail. It is shown that the characteristics of the band gaps, GH shifts, and phase variations depend crucially on the incident angle, number of periods, and layer thickness.

Quasiperiodic photonic crystal fiber [Invited

In the fields of light manipulation and localization, quasiperiodic photonic crystals, or photonic quasicrystals (PQs), are causing an upsurge in research because of their rotational symmetry and long-range orientation of transverse lattice arrays, as they lack translational symmetry. It allows for the optimization of well-established light propagation properties and has introduced new guiding features. Therefore, as a class, quasiperiodic photonic crystal fibers, or photonic quasicrystal fibers (PQFs), are considered to add flexibility and richness to the optical properties of fibers and are expected to offer significant potential applications to optical fiber fields. In this review, the fundamental concept, working mechanisms, and invention history of PQFs are explained. Recent progress in optical property improvement and its novel applications in fields such as dispersion control, polarization-maintenance, supercontinuum generation, orbital angular momentum transmission, plasmon-based sensors and filters, and high nonlinearity and topological mode transmission, are then reviewed in detail. Bandgap-type air-guiding PQFs supporting low attenuation propagation and regulation of photonic density states of quasiperiodic cladding and in which light guidance is achieved by coherent Bragg scattering are also summarized. Finally, current challenges encountered in the guiding mechanisms and practical preparation techniques, as well as the prospects and research trends of PQFs, are also presented.

A combination of angle insensitive stopband/passband filters based on one-dimensional hyperbolic metamaterial quasiperiodic photonic crystals.

In the present work, we demonstrate the transmittance properties of one dimensional (1D) quasi-periodic photonic crystals that contain a superconductor material and a hyperbolic metamaterial (HMM). A HMM layer is engineered by the subwavelength undoped and doped Indium Arsenide (InAs) multilayers. Many resonance peaks with angle stability are obtained from the proposed Fibonacci sequence structure using the transfer matrix method (TMM). In this case, the Fibonacci sequence serves as the mainstay in the design of our structure. The permittivity of the utilized superconductor and the HMM are also analyzed, respectively. The numerical findings showed that the incident angle has no effect on the wavelength positions of the resonance peaks. The effects of many parameters such as the superconductor material thickness, Fibonacci sequence number, and sequence type are discussed for the proposed structure. At various operating temperatures and superconductor material types, the transmittance characteristics of the proposed structure were also examined. The designed structure can serve as a combination of pass/stop band filters for near-infrared (NIR) applications.

Consequence of Fibonacci quasiperiodic sequences in 1-D photonic crystal refractive index sensor for the blood plasma and cancer cells detections

We present the consequences of different Fibonacci quasiperiodic sequences on the sensing performance of a one-dimensional (1D) photonic crystal (PC) based sensor to detect the blood plasma and cancer cells. We demonstrate that the sensitivity and figure of merit (FOM) of the sensor can be modulated, respectively, from 427.5 nm/RIU to 530 nm/RIU and from 162.5 RIU−1 to 2983.33 RIU−1 by utilizing the pertinent sensor structures with Fibonacci generation and structural parameters for the analyte refractive index from 1.31 to 1.41. We have also shown that the operational sensing wavelengths and sensitivity can be changed significantly by introducing the different Fibonacci sequences in the proposed sensor. The sensing peaks separation, FWHM, and sensitivity can also be tuned by changing the analyte and PC stacked layers' thicknesses. We also introduce the sensing performances for the Blood plasma and Cancer cells detection using the proposed Fibonacci quasiperiodic PC sensor. We observe that the maximum sensitivities and FOM of the proposed sensor are 552.5 nm/RIU and 2986.93 RIU−1 for cancer cells and 553.55 nm/RIU and 2214.21 RIU−1 for blood plasma, respectively. The proposed structure reveals the tunable sensing performances and stimulates the fabrication interest.

Interface Edge Mode Confinement in Dielectric-Based Quasi-Periodic Photonic Crystal Structure

In this paper, the localization of optical interface edge-states is analyzed for a dielectric material-based quasi-periodic photonic crystal (QPhC) structure. The design comprises a bilayer PhC structure, where layers are arranged in a Fibonacci configuration to introduce quasi-periodicity. The impact of local symmetric sub-structures on Eigenstate coupling is considered over a wider wavelength range. This confirms the localization of interface edge modes for different wavelengths at the structural local resonators, where the number of local resonators depends on the length of the QPhC. The proposed seven-element QPhC structure shows a strong Tamm-like top interface edge mode localization for a 45.04° incident angle at 750 nm operating wavelength, whereas a bulk interface guided mode is also excited for a higher incident angle of around 79°. The investigation facilitates the development of reconfigurable devices to excite both bulk interface and surface interface edge modes with improved field intensities for spectroscopy and sensing applications.

Optical fractal resonances in Cantor-like photonic crystals.

We theoretically investigate the optical fractal effect in one-dimensional quasiperiodic photonic crystals (PCs). Dielectric multilayers arrayed alternately submit to the Cantor-like sequence rule. The optical fractal phenomenon is induced by modulating the generation number of the dielectric sequence. The optical fractal effect corresponds to a series of resonant modes, and the Cantor-like PCs approve more resonance modes than those in the Cantor PCs with the same order number. The transmission channels of resonances exponentially increase with the increase in the sequence generation number. Furthermore, the central waves of the transmission channels can be regulated by the incident angle flexibly. We expect this paper may pave a new way for the development of wavelength division multiplexers.

Quasi-periodic one-dimensional photonic crystal as a perspective structures for nanophotonics: Analysis of transmittivity spectra

The characteristic matrix approach is used to evaluate optical transmission spectra for a 1D multilayered photonic system. The characteristics of transmittance are analyzed for different incident angles, layer thicknesses (from a few to hundred nanometers), and electron densities for the light wave propagating through both periodic and quasi-periodic photonic structures. The shifting trend of photonic band gap in the infrared wavelength regimes is observed for different types of quasi-sequence. Increased electron density, on the other hand, makes the band gap more robust, although collision frequency has a minor effect on the band gap. Moreover, the physical entities play a key role in the appearance of multiple band gaps in the greater wavelength regimes. For example, such nanophotonic devices as optical bandpass filters in the infrared regime can be designed by using the concept of the proposed structure. We further show that the suggested quasi-periodic multilayered structures can function as resilient adjustable photonic lattices with the above-mentioned properties that can be tuned.

Polarization-independent wide-angle flexible multiband thermal emitters enabled by layered quasi-periodic photonic crystal

An efficient, flexible multi-band thermal emitter is proposed in the present work, consisting of a one-dimensional quasi-periodic photonic crystal and a reflective substrate. All the materials involved in the design have good high-temperature stability. Compared to absorbers with complex shapes, our planar devices are easier to fabricate, lithography-free, large-scale, and cost-effective fabrication. It is found that more and narrower absorption peaks will be generated when more layers of the quasi-periodic photonic crystal composite layer are placed on the top of the metal substrate. All three absorption peaks have the absorbance of more than 97% for the three-cell device we designed. Since the designed emitter has excellent substrate adaptability and is insensitive to polarization and incident angle, it is favourable to fabricate on flexible substrates. The present work may find promising applications in high-temperature and flexibility research areas such as infrared detection.

Hofstadter butterfly and topological edge states in a quasiperiodic photonic crystal cavity array.

Quasiperiodic structures with additional synthetic degrees of freedom have recently been recognized as a promising way for investigating high-dimensional topological phases with lower physical dimensions. Here, we investigated the well-known Harper-Aubry-André model on an integrated photonic platform by proposing a new design of a quasiperiodic photonic crystal (PhC) cavity array. This array is composed of closely coupled H1 PhC cavities with their cavity lengths being periodically modulated in the real space. The frequency spectrum of the structure shows the main features of the Hofstadter butterfly, which is one of the most important phenomena in the Harper-Aubry-André model. By varying the modulation phase, this structure exhibits nontrivial topology, which supports strongly localized topological edge states. These results have shown that quasiperiodic PhC cavity arrays can serve as the testbed for studying topological phases and new topological phenomena on an integrated platform.

Design of an logic gate based on Sunflower six-fold quasi-periodic photonic crystal

Design of an logic gate based on Sunflower six-fold quasi-periodic photonic crystal

Omnidirectional photonic band gap based on nonlinear periodic and quasi-periodic photonic crystals

Omnidirectional photonic band gap based on nonlinear periodic and quasi-periodic photonic crystals

Cross-waveguide based on sunflower-type eightfold quasiperiodic magnetic photonic crystal

Nonreciprocal waveguides play a key role in optical communication devices due to their robustness in unidirectional transmission along the edge. We proposed a unidirectional air guide waveguide structure based on eightfold sunflower quasiperiodic magnetic photonic crystal (PC) that has a large working bandwidth, high transmission efficiency, and strong stability. A cross-waveguide is constructed in the sunflower-type eightfold quasiperiodic magnetic PC structure. It can be used as a single-pole double-throw switch by changing the external bias magnetic field direction, in which the isolation is over 28 dB in the microwave band from 4.21 to 4.5 GHz and insertion loss is close to 0.001 dB. It can also achieve 1 × 2 or 1 × 3 equal ratio beam splitting, with a total transmission rate of close to 100% and transmission loss of 0.001 dB. The cross-waveguide is simple in structure and easy to integrate and manufacture, and it has a wide range of functions that have tremendous potential applications in optical communication systems.

Magneto‐Optical Goos−Hänchen Displacement in Quasiperiodic Gradient 1D Photonic Crystal

In recent years, various approaches for GH (Goos−Hänchen) displacement control have been proposed, including various waveguide structures, different material interfaces, and other physical phenomena (such as surface plasmon resonance, etc.), which make GH displacement flexible and controllable. Herein, the magneto‐optic GH displacement in quasiperiodic gradient 1D photonic crystals is introduced. The variation of GH displacement by changing the magnetic field for periodic and quasiperiodic structures is shown. The thickness of the initial material is determined by the change of the material thickness, and then the tunable GH displacement is observed under the applied magnetic field. The GH value increases with the thicker gradient thickness but decreases with increase in magnetic field, and it is more sensitive to the magnetic field intensity.

TPP-assisted multi-band absorption enhancement in graphene based on Fibonacci quasiperiodic photonic crystal

The multi-channel enhanced absorption properties in graphene monolayer are theoretically studied. It is realized by inserting a graphene monolayer in a dielectric film, which is sandwiched between a metallic film and a Fibonacci quasiperiodic structure. It is shown that three peaks with absorbance above 75% can be achieved, which is attributed to the Tamm plasmon polaritons and multiple photonic stopbands of the Fibonacci dielectric multilayers. Moreover, the distribution of the normalized electric field intensity is simulated to reveal the physical origin of such multichannel absorption effect. The designed graphene absorber possesses ultra-narrow absorption profiles and performs similar to an antenna. Furthermore, the multichannel absorption performances could be flexibly tuned by changing the angle of the incident and the geometric dimensions. Our results may find potential applications in the design of novel photoelectronic devices.