Omnidirectional Photonic Band Gap Research Articles

Tunable large omnidirectional photonic bandgap in a one-dimensional photonic crystal comprising elliptical metamaterials based on elasto-optic effect

Tunable large omnidirectional photonic bandgap in a one-dimensional photonic crystal comprising elliptical metamaterials based on elasto-optic effect

Angular dependence of photonic band gap and omni-directional reflection in one-dimensional photonic crystal applied to a thermophotovoltaic device

In this work, we present a theoretical study and a numerical simulation on omnidirectional reflection in one-dimensional photonic crystal structures for a thermophotovoltaic device. The optical properties are determined using the transfer matrix method. The results show that the angular dependence of photonic bandgaps depends on refractive index contrast and, polarization. However, for both TE and TM polarization, a reflectivity peak with 100% reflectivity is observed. The Te/SiO2 structure is the one with the largest bandwidth of omnidirectional photonic band gap compared with the TiO2/SiO2 and Si/SiO2 structures. The results also show that by designing a giant birefringent optical the Brewster’s angle allows angle the control at any angle for both TE and TM mode.

Blue-Noise-Based Disordered Photonic Structures Show Isotropic and Ultrawide Band Gaps

Spatially disordered but uniformly distributed point patterns characterized by so-called blue-noise long-range spatial correlations are of great benefit in computer graphics, especially in spatial dithering thanks to the spatial isotropy. Herein, the potential photonic properties of blue-noise disordered, homogeneous point processes based on farthest-point optimization are numerically investigated for silicon photonics. The photonic properties of blue-noise two-dimensional patterns are studied as a function of the filling fraction and benchmarked with photonic crystals with a triangular lattice. Ultrawide and omnidirectional photonic band gaps spanning most of the visible spectrum are found with estimates of gap–midgap ratios of up to 55.4% for transverse magnetic polarization, 59.4% for transverse electric polarization, and 32.7% for complete band gaps. The waveguiding effect in azimuthal defect lines is also numerically evaluated. These results corroborate the idea that long-range correlated disordered structures are helpful for engineering novel devices with the additional degree of freedom of spatial isotropy, and capable of bandgap opening even without total suppression of infinite-wavelength density fluctuations.

Ultra-large near-infrared omnidirectional photonic bandgaps in cascaded one-dimensional photonic crystals containing all-dielectric metamaterials.

In conventional one-dimensional (1-D) photonic crystals (PCs) consisting of isotropic dielectrics, photonic bandgaps (PBGs) substantially shift toward shorter wavelengths as incident angle increases. This strong blueshift characteristic of PBGs significantly reduces the widths of near-infrared omnidirectional photonic bandgaps (OPBGs). Recently, researchers achieved a kind of special PBG called angle-insensitive PBGs in 1-D PCs containing all-dielectric elliptical metamaterials (EMMs). The emergence of angle-insensitive PBGs provides us a possibility to achieve ultra-large near-infrared OPBGs. Herein, we design two 1-D PCs containing all-dielectric EMMs with near-infrared angle-insensitive PBGs in different wavelength ranges. By cascading two 1-D PCs containing all-dielectric EMMs together, we achieve an ultra-large near-infrared OPBG with a width up to 1.004µm (relative bandwidth of 63.9%). In addition, the width of the near-infrared OPBG demonstrates robustness against the layer thickness. Our work not only provides a feasible route to achieving ultra-large near-infrared OPBGs, but also facilitates the design of broadband omnidirectional mirrors.

Large omnidirectional mid-infrared photonic bandgap in a one-dimensional ternary photonic crystal consisting of isotropic dielectric, elliptical metamaterial and plasma

Photonic bandgaps (PBGs) in traditional one-dimensional (1-D) binary photonic crystals (PhCs) consisting of two kinds of isotropic dielectrics strongly shift towards shorter wavelengths as incident angle increases. Such blueshift property of PBGs intensively limits the widths of omnidirectional photonic bandgaps (OPBGs). Very recently, researchers achieved a special kind of PBGs called angle-insensitive PBGs in novel 1-D binary PhCs consisting of isotropic dielectric and elliptical metamaterial (EMM). The emergence of such angle-insensitive PBGs provides us an opportunity to achieve large OPBGs. Herein, we periodically introduce plasma layers into a 1-D binary PhC consisting of isotropic dielectric and EMM with an angle-insensitive PBG to achieve a large OPBG at mid-infrared wavelengths. The EMM is mimicked by an all-dielectric subwavelength multilayer. The broaden effect of the OPBG originates from the plasmonic property of plasma and the angle-insensitive property of the PBG. The width of the OPBG reaches 4.19 μm. Our work provides a feasible route to achieving large OPBGs in 1-D PhCs and would promote the development of OPBG-based devices, such as omnidirectional broadband reflectors and omnidirectional filters.

Multiplication of photonic band gaps in one-dimensional photonic crystals by using hyperbolic metamaterial in IR range

The light-slowing effect near band endpoints is frequently exploited in photonic crystals to enhance the optical transmittance. In a one-dimensional binary photonic crystal (1DPC) made of hyperbolic metamaterials (HMMs), we theoretically examined the angle-dependent omnidirectional photonic bandgap (PBG) for TM polarization. Using the transfer matrix approach, the optical characteristics of the 1DPC structure having dielectric and HMM layers were examined at the infrared range (IR). As such, we observed the existing of numerous PBGs in this operating wavelength range (IR). Meanwhile, the HMM layer is engineered by the subwavelength dielectric- nanocomposite multilayers. The filling fraction of nanoparticles have been explored to show how they affect the effective permittivity of the HMM layer. Furthermore, the transmittance properties of the suggested structure are investigated at various incident angles for transverse magnetic (TM) and transverse electric polarizations. Other parameters such as, the permittivity of the host material, the filling fraction of nanoparticles, and the thickness of the second layer (HMM) are also taken into account. Finally, we investigated the effect of these parameters on the number and the width of the (PBGs). With the optimum values of the optical parameters of the nanocomposite (NC) layer, this research could open the way for better multi-channel filter photonic crystals.

Terahertz angle-independent photonic bandgap in a one-dimensional photonic crystal containing InSb-based hyperbolic metamaterials.

According to the Bragg scattering theory, terahertz (THz) photonic bandgaps (PBGs) in all-dielectric one-dimensional (1-D) photonic crystals (PhCs) are strongly dependent on the incident angle. Such a strongly angle-dependent property of the PBGs not only limits the widths of omnidirectional PBGs, but also causes the strongly angle-dependent property of defect modes and optical Tamm states in multilayer structures containing all-dielectric 1-D PhCs. Until now, ways to achieve a THz angle-independent PBG have been an open problem. Herein, according to the existing phase-variation compensation theory, we achieve a THz angle-independent PBG in a 1-D PhC containing indium antimonide (InSb)-based hyperbolic metamaterials for transverse magnetic polarization. Different from conventional strongly angle-dependent PBGs, the angle-independent PBG remains almost unshifted as the incident angle changes. The relative frequency shifts of the upper and the bottom edges of the angle-independent PBG are only 1.4% and 0.4%, respectively. Besides, the angle-independent property of the PBG is robust against the disturbance of the layer thickness. The proposed 1-D PhC composes only two frequently used materials: silicon (Si) and InSb. Such a Si/InSb multilayer can be fabricated by the current ion-assisted electron beam coating or spin coating techniques. This THz angle-independent PBG would be utilized to design THz omnidirectional filters or absorbers.

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

Omnidirectional photonic band gaps in one-dimensional gradient refractive index photonic crystals considering linear and quadratic profiles

By using the transfer matrix formalism, in this work it is presented the study of the optical properties of 1D photonic structures constructed with M periods of bilayers of dielectric material and slabs with gradient refractive index (GRIN) profile of two types: linear and quadratic. By varying the profile parameters, preserving the average value of the refractive index for the GRIN slab, the results show the formation of new photonic band gaps whose bandwidths depends on the slope and the curvature of the linear and quadratic profile respectively. Also, it can be observed the formation of omnidirectional photonic bandgaps for the TE and TM polarizations, one for the linear profile and three for the quadratic one, for which their bandwidths depend linearly on the slope and the curvature of the GRIN profiles. It is expected that the presented results could be useful in the construction of optical devices based in their optical response under oblique incidence.

Omnidirectional Photonic Bandgap in Two-dimensional Photonic Quasicrystal Made of Near-Transparent Dielectric Material

Complete bandgap for all-dielectric photonic crystals in the microwave region can be obtained only by using high-contrast materials. This requires the usage of dielectric materials with high relative permittivity coefficient. In this paper, we study, both numerically and experimentally, a two-dimensional all-dielectric photonic quasicrystal made of polyurethane foam, which is considered in all microwave applications as a transparent material. The quasicrystal structure having an omnidirectional two-dimensional bandgap is mathematically generated by the direct inscription of Bragg’s peaks of the structure in the reciprocal space. The sample of the quasicrystal was manufactured on CNC (computer numerical controlled) milling machine out of foam with very low dielectric permittivity of 1.254. The numerical simulations and the experimental study are in good agreement with the theoretical model.

Omnidirectional photonic bandgap in one-dimensional photonic crystals containing hyperbolic metamaterials.

We theoretically and experimentally investigate the angle-dependent omnidirectional photonic bandgap (PBG) in one-dimensional photonic crystals (PCs) comprising hyperbolic metamaterials (HMMs) for TM polarization, which is different from blue-shifted PBG in conventional all-dielectric photonic crystals. The frequency range of PBG increases when the incident angles increase, owing to the red-shift and blue-shift of the long-wavelength and short-wavelength band edges, respectively. The red-shifted band edge originates from the phase-variation compensation mechanism between the HMMs and dielectric material. The experimental values are in good agreement with the simulation results. These nanostructures are ideal for fabricating photonic devices such as omnidirectional reflectors.

Optimized Omnidirectional High-Reflectance Using Octonacci Photonic Crystal for Thermographic Sensing Applications

The transmittance of waves through one-dimensional periodic and Octonacci photonic structures was studied using the theoretical transfer matrix method for both wave-polarization-modes. The first structures were made up of the SiO2 and TiO2 materials. The objective here was to obtain a broad omnidirectional high reflector covering the infrared spectrum of a thermographic camera [1–14µm] and, especially, to prevent the transmission of emitted human body peak radiation λmax = 9.341 µm. By comparing the periodic and Octonacci structures, we found that the last structure presented a main and wide photonic band gap near this human radiation. For that, we kept only the Octonacci structure for the rest of the study. The first structure did not give the aspired objective; thus, we replaced the TiO2 layers with yttrium barium copper oxide material, and a significant enhancement of the omnidirectional photonic band gap was found for both TE and TM polarization modes. It was shown that the width of this band was sensitive to the Octonacci iteration number and the optical thickness (by changing the reference wavelength), but it was not affected by the ambient temperature. The number of layers and the thickness of the structure was optimized while improving the omnidirectional high reflector properties.

Omnidirectional terahertz photonic band gap broaden effect in one-dimensional photonic crystal containing few-layer graphene

We study the influence of few-layer graphene on omnidirectional photonic band gap (OPBG) in one-dimensional photonic crystal (1DPC) at terahertz frequencies. By periodically introducing few-layer graphene into 1DPC, the width of OPBG can be greatly broadened. As the layer number of introduced graphene increases, the broaden effect of the OPBG becomes stronger. The physical reason behind the broaden effect is that the few-layer graphene acts like an ultrathin metal layer within the frequency range of the OPBG. Besides, the width of the OPBG can be dynamically tuned by the gate voltage of graphene. Compared to 1DPCs containing metal layers, 1DPCs containing few-layer graphene possess lower absorptive loss and more flexible tunability. Our works provides a route and practical way to promote various applications based on tunable terahertz OPBGs.

Ultra-large omnidirectional photonic band gaps in one-dimensional ternary photonic crystals composed of plasma, dielectric and hyperbolic metamaterial

Abstract Owing to the Bragg interference mechanism, photonic band gap (PBG) in all-dielectric one-dimensional photonic crystal (PC) is strongly sensitive to the incident angle, which limits the width of omnidirectional photonic band gap (OPBG). Recently, researchers realized a kind of special PBG called angle-insensitive PBG in one-dimensional binary PC composed of alternating dielectric and hyperbolic metamaterial (HMM) layers. Different from the conventional strongly angle-insensitive PBG, this kind of PBG is angle-insensitive and naturally omnidirectional, providing us an efficient way to achieve ultra-large OPBG. In this paper, by periodically introducing plasma layers into one-dimensional binary PC composed of alternating dielectric and HMM layers with angle-insensitive PBG, we find that the PBG can be efficiently broadened. Although the PBG becomes slightly angle-sensitive since the introduction of plasma layers breaks the phase variation compensation condition, the width of OPBG can still be efficiently broadened. Under the proper design, we achieve an ultra-large OPBG with the width up to 1321 nm (68% relative bandwidth) in the one-dimensional ternary PC composed of alternating plasma, dielectric and HMM layers at near-infrared wavelengths. The whole one-dimensional ternary PC is composed of only three kinds of materials: indium tin oxide (ITO), silicon (Si) and silicon carbide (SiC), which can be fabricated by the atomic layer deposition (ALD) method under the current experimental conditions. This ultra-large OPBG in simple one-dimensional structure could be utilized to design ultra-broadband omnidirectional optical mirror and narrowband optical filter with ultra-large omnidirectional stopband.

Thermally tunable terahertz omnidirectional photonic bandgap and defect mode in 1D photonic crystals containing moderately doped semiconductor

A new one-dimensional photonic crystal (1DPC) containing moderately doped silicon (m-Si) semiconductor is proposed and its tunable properties are theoretically investigated. The tunable complex permittivity of m-Si with temperature is the central idea that makes the 1DPC thermally tunable. The 1DPC systems such as (m-Si/SiO2)12 and defective (m-Si/SiO2)6D(m-Si/SiO2)6 are examined in the spectral range of 0.4–0.8 THz with varying temperature from 40 to 100 K. Air and m-Si are considered as defect layer (D) in two different 1DPC systems. Our simulation shows that the photonic band gap (PBG) shifts to higher frequency and the omnidirectional PBG gets narrower with increasing temperature. The defect mode in both defective 1DPCs shifts to higher frequency with increasing temperature. The temperature sensitivity of peak transmission is found better in the air defective 1DPC, while that of defect frequency is better in the m-Si defective 1DPC. The angle of incidence and polarization dependency of the defect modes are studied in detail. The present work can be utilized for the development of tunable omnidirectional mirrors and narrow bandpass filters in the terahertz region as well as THz light based thermal sensors.

Truncated Metallo-Dielectric Omnidirectional Reflector: Collecting Single Photons in the Fundamental Gaussian Mode with 95% Efficiency

We propose a novel antenna structure which funnels single photons from a single emitter with unprecedented efficiency into a low-divergence fundamental Gaussian mode. Our device relies on the concept of creating an omnidirectional photonic bandgap to inhibit unwanted large-angle emission and to enhance small-angle defect-guided-mode emission. The new photon collection strategy is intuitively illustrated, rigorously verified and optimized by implementing an efficient body-of-revolution finite-difference time-domain method for in-plane dipole emitters. We investigate a few antenna designs to cover various boundary conditions posed by fabrication processes or material restrictions and theoretically demonstrate that collection efficiencies into the fundamental Gaussian mode exceeding 95% are achievable. Our antennas are broadband, insensitive to fabrication imperfections and compatible with a variety of solid-state emitters such as organic molecules, quantum dots and defect centers in diamond. Unidirectional and low-divergence Gaussian-mode emission from a single emitter may enable the realization of a variety of photonic quantum computer architectures as well as highly efficient light-matter interfaces.

A type of arrangement for photonic crystal structures interacting with a Terahertz wave with omnidirectional and thermal effects

Omnidirectional photonic bandgaps are a new special type of one-dimensional quasi-photonic crystals that contains semiconductor and dielectric material layers and are investigated here in the Terahertz wave range. The proposed medium is constructed with a special type of layer arrangement, which uses both the Fibonacci sequence as a quasi-periodic sequence and the absolute periodic sequence in a period. As the Terahertz bandgaps of the transmittance spectrum are essential in some devices, the tuning and manipulation of these bandgaps has been of great interest in recent years. One of the best methods of manipulating these bandgaps to reach the desired outcome is by changing their arrangement using different types of quasi-periodic sequences in the structure. The beneficial results of applying these sequences have been clearly observed. So, we propose another new type of arrangement here in order to completely satisfy the changing methods of the photonic crystal structures. According to the results of the current investigation, it has been demonstrated that the proposed arrangement could be used to achieve a wide variety of desirable states. The semiconductor could make the bandgaps tunable via temperature changes through its thermally tunable permittivity. These types of media, which can operate as tunable Terahertz filters and mirrors, offer many promising omnidirectional Terahertz components and devices.

Investigation on temperature controlling multifunctional selector in superconducting photonic crystals based on Thue–Morse sequence

In this paper, a novel one-dimensional superconducting photonic crystal exploiting the Thue–Morse arrangement is theoretically investigated by the transfer matrix method. Two transmission states are switched in utilization of ambient temperature in the case of the same structure in the terahertz regime: one is the omnidirectional photonic bandgap (OBG) characteristics in low-temperature zones (about 10 K), and the other is wide-angle broadband absorption characteristics in high-temperature zones (about 90 K). Due to the modulation of temperature-dependent superconducting complex permittivity, the proposed structure can induce the OBG and broadband absorption at different temperatures. From the numerical results, the OBG can be notably tuned by manipulating the structural parameter of high refractive index dielectric. The effects of superconducting thickness on the switchable function regions are also considered. The proposed structure can possess both environment stable zero- n ¯ OBG at 10 K and preeminent broadband absorption in the TM polarization at 90 K, which offers theoretical guidance to the design of temperature switchable function selectors.

Temperature-switchable mode selector in superconducting photonic crystals based on the Thue–Morse sequence

In this paper, a novel one-dimensional superconducting photonic crystal based on the quasi-periodic Thue–Morse (ThM) arrangement is theoretically investigated by the transfer matrix method, which can switch two transmission properties by controlling ambient temperature. Its transmission spectrum realizes omnidirectional photonic band gap (OBG) characteristics in low-temperature zones (about 10 K) and wide-angle broadband absorption characteristics in high-temperature zones (about 90 K) as the whole structure remains the same in the terahertz regime. The intrinsic reason for switchable functions can be ascribed to the superconducting negative permittivity that is dependent on both temperature and frequency under the superconducting state, which causes an OBG corresponding to the zero-averaged (volume) refractive index (zero- n ¯ ) and broadband absorption induced by high permittivity dissipation. From the numerical results, the OBG from the Bragg gap or absorption bandwidth can be notably tuned by manipulating the periodicity of the ThM sequence and dielectric or superconducting thicknesses. The effects of incident angle and polarization modes on the proposed structure are also considered. We report that the proposed structure has a preeminent zero- n ¯ OBG ranging from 0.1 to 1.7 THz at 10 K and stable broadband absorption for a wide angle (at most 70 deg) in TM mode at 90 K, which provides theoretical guidance for the design and application of the temperature-switchable mode selector.

Microwave multichannel tunable filter based on transmission and reflection properties of 1D magnetized plasma photonic crystal heterostructures

The transmission and reflection properties of one-dimensional magnetized plasma photonic crystal heterostructures have been theoretically investigated. The proposed structure is composed of two sub-PCs containing magnetized cold plasma and lossless dielectric materials. The optical properties of the structure are suitable for multichannel tunable transmission filter and omnidirectional band-stop filters applications. The investigations have been carried out by applying transfer matrix method and employing electrostatic boundary conditions for TE and TM wave, respectively, in microwave region. The transmission spectra of the proposed structure possess external magnetic field-dependent 3N − 3 comb-like resonant peaks called as transmission channels for period number (N) > 1. Due to multiple interactions between forward and backward decaying evanescent waves in plasma and dielectric layers, respectively, 3N − 3 transmission channels are found in defect-free magnetized plasma photonic crystal heterostructure, enabling the structure to work as a multichannel filter. Next, the filter properties have been made tunable, i.e., channel frequency of each channel can either be red or blue shifted, depending upon the RHP and LHP configurations of external magnetic field under magneto-optical Faraday effect, respectively. The number of channels and their positions can also be modulated by changing the number of periods (N) and the incident angle (θ0) for TE and TM waves both besides other plasma parameters. Apart from the transmission properties of the proposed structure, we have also studied the reflection properties to obtain multichannel tunable omnidirectional photonic band gaps under the influence of external magnetic field. These results may be utilized to develop new kind of externally tunable single to multichannel omnidirectional band-stop filters.