Two-dimensional Plasma Photonic Crystals Research Articles

Designing externally controllable optical filters with two-dimensional magnetized plasma photonic crystals

Designing externally controllable optical filters with two-dimensional magnetized plasma photonic crystals

Bandgap structure and density of states of two-dimensional magnetized plasma photonic crystals

In this paper, we study dispersion properties in a two-dimensional magnetized plasma photonic crystal, based on the modified plane wave expansion method. Transverse electric polarization is considered. The influence of different factors such as external magnetic field, lattice constant, dielectric constants of background and central rod, and electron density of plasma in photonic bandgap structure and photonic bandgap map is studied. The photonic density of states is also demonstrated. Results show that a large magnetic field produces more band gaps in higher frequencies. The lattice constant is an important factor in controlling the bandgap structure and it can compensate low magnetic field effect. Using a larger dielectric constant in the background compared to the central dielectric rod leads to more and sharper band gaps in higher frequencies. Electron density of plasma plays an important role in tuning bandgap structure. There would be three or four band areas in the band structure and the band frequencies are larger than the cutoff frequency of plasma.

Two-dimensional plasma photonic crystal structure transmission characteristics

This paper use the finite difference time domain (FDTD) algorithm to study the forbidden band characteristics of two-dimensional non-magnetized plasma photonic crystals. We analyse the obtained S-parameter from the perspective of frequency domain, and discuss the influence of the interlayer angle and distance of the photonic crystal, the polarization mode of the antenna and the plasma parameters on the band gap characteristics. The results show that when the photonic crystal has a certain plasma filling rate, different angles and distances between layers and different polarization modes can achieve modulation of transmission characteristics.

Study on transmission characteristics of two-dimensional defective plasma photonic crystals

Several defective plasma photonic crystals were designed based on crystal edge dislocations, and their transmission characteristics were studied using CST software. The transmission characteristics of PPC with different defects in TM mode are mainly discussed. Compare defective PPCs to non-defective PPCs and other defective PPCs. Defective plasma photonic crystals with the largest changes in PPC electromagnetic characteristics were obtained. This type of defective photonic crystals can create a band gap in a certain frequency band and control its movement through defect parameters.

Complete photonic band gap characteristics of two-dimensional Kerr nonlinear plasma photonic crystals

In this paper, the characteristics of the complete photonic band gaps for two-dimensional nonlinear plasma photonic crystals are studied theoretically by using the finite-difference time-domain method. The two-dimensional structure comprises nonlinear rods with different geometrical shapes and orientations in a plasma background with square and honeycomb lattices. The embedded dielectric rods containing Kerr nonlinearity have a relative permittivity that is a function of the external light intensity. Our simulation results show that almost all designed nonlinear structures represent noticeable complete band gaps whose position and width can be tuned by altering the light intensity. Furthermore, the influence of geometrical parameters on properties of the band spectra is discussed.

The absorber realized by 2D photonic crystals with plasma constituents

Herein, a tunable metamaterial absorber was realized by using two-dimensional (2D) plasma photonic crystals (PPCs). A photonic band gap (PBG) can be obtained in the proposed 2D PPCs, which runs at frequencies from 1.7 to 1.93 GHz. The fabricated absorber is tunable and is composed of excited plasma tubes with 2D square lattices. The resonances originate from the all-dielectric resonances. The plasma frequency is also measured. The experimental results agree with the simulation results. The fabricated absorber shows excellent absorption (up to 84.3%). Hence, it can be used to design various devices, such as tunable microwave devices, stealth devices, and reconfigurable antennas.

Investigations on the two-dimensional aperiodic plasma photonic crystals with fractal Fibonacci sequence

In this paper, the properties of photonic band gaps (PBGs) and defect modes of two-dimensional (2D) fractal plasma photonic crystals (PPCs) under a transverse-magnetic (TM) wave are theoretically investigated by a modified plane wave expansion (PWE) method. The configuration of 2D PPCs is the square lattices with the iteration rule of the Fibonacci sequence whose constituents are homogeneous and isotropic. The proposed 2D PPCs is filled with the dielectric cylinders in the plasma background. The accuracy and convergence of the present modified PWE method also are validated by a numerical example. The calculated results illustrate that the enough accuracy and good convergence can be achieved compared to the conventional PWE method, if the number of meshed grids is large enough. The dispersion curves of the proposed PPCs and 2D PPCs with a conventional square lattice are theoretically computed to study the properties of PBGs and defect modes. The simulated results demonstrate that the advantaged properties can be obtained in the proposed PPCs compared to the 2D conventional PPCs with similar lattices. If the Fibonacci sequence is introduced into the 2D PPCs, the larger PBGs and higher cutoff frequency can be achieved. The lower edges of PBGs are flat, which are originated from the Mie resonances. The defect modes can be considered as the quasi-localized states since the Fibonacci sequence has the self-similarity and non-periodicity at the same time. The effects of configurational parameters on the characters of the present PPCs are investigated. The results show that the PBGs and defect modes can be easily manipulated by tuning those parameters.

The properties of two-dimensional fractal plasma photonic crystals with Thue-Morse sequence

In this paper, the properties of the acceptor modes and photonic band gaps (PBGs) of two-dimensional (2D) fractal plasma photonic crystals (PPCs) under a transverse-magnetic wave are theoretically studied by a modified plane wave expansion method. The density of states is calculated to elaborate the characteristics of the proposed 2D PPCs in which the dielectric cylinders are inserted in the plasma background according to the iteration rule of the Thue-Morse sequence with square lattices. The band structures of the proposed PPCs and 2D PPCs with a conventional square lattice are numerically determined to analyse the properties of PBGs and acceptor modes. The results illustrate that the performance is improved in the proposed PPCs compared to the 2D conventional PPCs with similar lattices. The larger PBGs and higher cutoff frequency are obtained when the Thue-Morse structure is introduced. The lowest edges of PBGs are flat, and they are originated from the Mie resonances. The acceptor modes can be considered as the quasi-localized states since the Thue-Morse sequence has the self-similarity and non-periodicity at the same time. The influences of configurational parameters on the properties of the proposed PPCs are studied in detail as well. The results demonstrate that the PBGs and acceptor modes can be easily tuned by changing those configurational parameters.

Full photonic band gap properties of plasma photonic crystals with triangular structure

In this study, we analyse full photonic band gap (PBG) properties of two-dimensional plasma photonic crystals (PCs) with triangular lattice, composed of anisotropic tellurium rods with different geometrical shapes immersed in plasma background. Using the finite-difference time-domain method, we discuss the maximization of the full PBG width as a function of tellurium rods parameters with different shapes and orientations. The numerical results show that our proposed structures represent significant large full PBGs in comparison to previously studied plasma PCs.

Enhanced the tunable omnidirectional photonic band gaps in the two-dimensional plasma photonic crystals

In this paper, the features of omnidirectional band gap (OBG) in the two-dimensional (2D) plasma photonic crystals (PPCs) with triangular lattices are theoretically studied in detail by the modified plane wave expansion method as the off-plane incidence wave vector is considered, which are composed of the non-magnetized plasma cylinders inserted into the homogeneous and isotropic dielectric background. The simulated results demonstrate that a flatband region and the OBG can be obtained in the proposed PPCs. The influences of the radius of inserted cylinder and plasma frequency on the OBG are investigated. The calculated results illustrate that not only the tunable OBG can be obtained but also the achieved OBG also can be enlarged by optimizing those parameters. To enhance the OBGs, two novel configurations of PPCs are present. The computed results reveal that the proposed two configurations have the advantages of obtaining the larger OBGs compared to the conventional 2D PPCs since the symmetry of 2D PPCs is broken, and the OBGs also can be manipulated obviously by changing the geometric parameters of such two PCs structures. Introducing the anisotropic dielectric (uniaxial material) into the proposed 2D PPCs to enlarge the OBGs also is studied. The effects of ordinary-refractive and extraordinary-refractive indices of uniaxial material on the properties of OBGs also are investigated in theory, respectively. The computed results show that the OBGs can be enlarged by introducing the uniaxial material, and the OBGs also can be tuned by changing the parameters of uniaxial material.

Modulation of large absolute photonic bandgaps in two-dimensional plasma photonic crystal containing anisotropic material.

The large absolute photonic bandgaps of two-dimensional (2D) anisotropic magnetic plasma photonic crystals with hexagonal and square lattices are obtained by introducing tellurium dielectric rods using the modified plane wave expansion method. Equations for calculating the band structures in the irreducible part of the first Brillouin zone are theoretically deduced. The modulation properties indicate that the location and bandwidth of the absolute photonic bandgaps (PBGs) could be tuned by filling factor, plasma frequency, and magnetic field. The effective tunable ranges and critical values of these parameters are found. These results could be helpful in designing 2D anisotropic PPCs with large absolute PBGs.

Analyzing the photonic band gaps in two-dimensional plasma photonic crystals with fractal Sierpinski gasket structure based on the Monte Carlo method

In this paper, the properties of photonic band gaps (PBGs) in two types of two-dimensional plasma-dielectric photonic crystals (2D PPCs) under a transverse-magnetic (TM) wave are theoretically investigated by a modified plane wave expansion (PWE) method where Monte Carlo method is introduced. The proposed PWE method can be used to calculate the band structures of 2D PPCs which possess arbitrary-shaped filler and any lattice. The efficiency and convergence of the present method are discussed by a numerical example. The configuration of 2D PPCs is the square lattices with fractal Sierpinski gasket structure whose constituents are homogeneous and isotropic. The type-1 PPCs is filled with the dielectric cylinders in the plasma background, while its complementary structure is called type-2 PPCs, in which plasma cylinders behave as the fillers in the dielectric background. The calculated results reveal that the enough accuracy and good convergence can be obtained, if the number of random sampling points of Monte Carlo method is large enough. The band structures of two types of PPCs with different fractal orders of Sierpinski gasket structure also are theoretically computed for a comparison. It is demonstrate that the PBGs in higher frequency region are more easily produced in the type-1 PPCs rather than in the type-2 PPCs. Sierpinski gasket structure introduced in the 2D PPCs leads to a larger cutoff frequency, enhances and induces more PBGs in high frequency region. The effects of configurational parameters of two types of PPCs on the PBGs are also investigated in detail. The results show that the PBGs of the PPCs can be easily manipulated by tuning those parameters. The present type-1 PPCs are more suitable to design the tunable compacted devices.

The Photonic Band Gaps in the Two-Dimensional Plasma Photonic Crystals with Rhombus Lattice

In this paper, under two different electromagnetic modes, the photonic band gaps (PBGs) in the two-dimensional plasma photonic crystals (PPCs) are theoretically investigated based on the plane wave expansion method. The proposed PPCs are arranged in rhombus lattices, in which the homogeneous unmagnetized plasma rods are immersed in the isotropic dielectric background. The computed results showed that PBGs can be easily tuned by the angle of rhombus lattices, and a cutoff frequency and a flatbands region can be observed under the TM and TE polarized waves, respectively. The relationships between the relative bandwidths of first PBGs and the parameters of PPCs in two such cases also are discussed. The numerical simulations showed that the PBGs can be manipulated obviously by the parameters as mentioned above. The proposed results can be used to design the waveguide and filter based on the PPCs.

Investigation on the properties of omnidirectional photonic band gaps in two-dimensional plasma photonic crystals

The properties of omnidirectional photonic band gaps (OBGs) in two-dimensional plasma photonic crystals (2D PPCs) are theoretically investigated by the modified plane wave expansion method. In the simulation, we consider the off-plane incident wave vector. The configuration of 2D PPCs is the triangular lattices filled with the nonmagnetized plasma cylinders in the homogeneous and isotropic dielectric background. The calculated results show that the proposed 2D PPCs possess a flatbands region and the OBGs. Compared with the OBGs in the conventional 2D dielectric-air PCs, it can be obtained more easily and enlarged in the 2D PPCs with a similar structure. The effects of configurational parameters of the PPCs on the OBGs also are studied. The simulated results demonstrate that the locations of OBGs can be tuned easily by manipulating those parameters except for changing plasma collision frequency. The achieved OBGs can be enlarged by optimizations. The OBGs of two novel configurations of PPCs with different cross sections are computed for a comparison. Both configurations have the advantages of obtaining the larger OBGs compared with the conventional configuration, since the symmetry of 2D PPCs is broken by different sizes of periodically inserted plasma cylinders or connected by the embedded plasma cylinders with thin veins. The analysis of the results shows that the bandwidths of OBGs can be tuned by changing geometric and physical parameters of such two PPCs structures. The theoretical results may open a new scope for designing the omnidirectional reflectors or mirrors based on the 2D PPCs.

Analyzing the properties of acceptor mode in two-dimensional plasma photonic crystals based on a modified finite-difference frequency-domain method

In this paper, the properties of acceptor mode in two-dimensional plasma photonic crystals (2D PPCs) composed of the homogeneous and isotropic dielectric cylinders inserted into nonmagnetized plasma background with square lattices under transverse-magnetic wave are theoretically investigated by a modified finite-difference frequency-domain (FDFD) method with supercell technique, whose symmetry of every supercell is broken by removing a central rod. A new FDFD method is developed to calculate the band structures of such PPCs. The novel FDFD method adopts a general function to describe the distribution of dielectric in the present PPCs, which can easily transform the complicated nonlinear eigenvalue equation to the simple linear equation. The details of convergence and effectiveness of proposed FDFD method are analyzed using a numerical example. The simulated results demonstrate that the enough accuracy of the proposed FDFD method can be observed compared to the plane wave expansion method, and the good convergence can also be obtained if the number of meshed grids is large enough. As a comparison, two different configurations of photonic crystals (PCs) but with similar defect are theoretically investigated. Compared to the conventional dielectric-air PCs, not only the acceptor mode has a higher frequency but also an additional photonic bandgap (PBG) can be found in the low frequency region. The calculated results also show that PBGs of proposed PPCs can be enlarged as the point defect is introduced. The influences of the parameters for present PPCs on the properties of acceptor mode are also discussed in detail. Numerical simulations reveal that the acceptor mode in the present PPCs can be easily tuned by changing those parameters. Those results can hold promise for designing the tunable applications in the signal process or time delay devices based on the present PPCs.

Complete photonic band gaps and tunable self-collimation in the two-dimensional plasma photonic crystals with a new structure

In this paper, the properties of complete photonic band gaps (CPBGs) and tunable self-collimation in two-dimensional plasma photonic crystals (2D PPCs) with a new structure in square lattices, whose dielectric fillers (GaAs) are inserted into homogeneous and nomagnetized plasma background are theoretically investigated by a modified plane wave expansion (PWE) method with a novel technique. The novel PWE method can be utilized to compute the dispersion curves of 2D PPCs with arbitrary-shaped cross section in any lattices. As a comparison, CPBGs of PPCs for four different configurations are numerically calculated. The computed results show that the proposed design has the advantages of achieving the larger CPBGs compared to the other three configurations. The influences of geometric parameters of filled unit cell and plasma frequency on the properties of CPBGs are studied in detail. The calculated results demonstrate that CPBGs of the proposed 2D PPCs can be easily engineered by changing those parameters, and the larger CPBGs also can be obtained by optimization. The self-collimation in such 2D PPCs also is discussed in theory under TM wave. The theoretical simulations reveal that the self-collimation phenomena can be found in the TM bands, and both the frequency range of self-collimation and the equifrequency surface contours can be tuned by the parameters as mentioned above. It means that the frequency range and direction of electromagnetic wave can be manipulated by designing, as it propagates in the proposed PPCs without diffraction. Those results can hold promise for designing the tunable applications based on the proposed PPCs.

The Absorbing Properties of Two-Dimensional Plasma Photonic Crystals

Plasma photonic crystals composed of periodic plasma and dielectric materials have attracted considerable attention because of their tunable photonic band gaps, but only their band structures or negative refractive index properties have been addressed in previous works. In this paper, through studying the transmission and reflection characteristics of two types of two-dimensional plasma photonic crystals, it is found that plasma photonic crystals play an important role in absorbing waves, and they show broader band and higher amplitude absorption characteristics than bulk plasmas. Also, the absorption of plasma photonic crystals can be tuned via plasma parameters; varying the collision frequency can make the bandwidth and amplitude tunable, but cannot change the central frequency, whereas varying the plasma frequency would control both the location and the amplitude of the absorbers. These features of plasma photonic crystals have potential for terahertz tunable absorber applications.

Tunable all-angle negative refraction and photonic band gaps in two-dimensional plasma photonic crystals with square-like Archimedean lattices

In this paper, the tunable all-angle negative refraction and photonic band gaps (PBGs) in two types of two-dimensional (2D) plasma photonic crystals (PPCs) composed of homogeneous plasma and dielectric (GaAs) with square-like Archimedean lattices (ladybug and bathroom lattices) for TM wave are theoretically investigated based on a modified plane wave expansion method. The type-1 structure is dielectric rods immersed in the plasma background, and the complementary structure is named as type-2 PPCs. Theoretical simulations demonstrate that the both types of PPCs with square-like Archimedean lattices have some advantages in obtaining the higher cut-off frequency, the larger PBGs, more number of PBGs, and the relative bandwidths compared to the conventional square lattices as the filling factor or radius of inserted rods is same. The influences of plasma frequency and radius of inserted rod on the properties of PBGs for both types of PPCs also are discussed in detail. The calculated results show that PBGs can be manipulated by the parameters as mentioned above. The possibilities of all-angle negative refraction in such two types of PPCs at low bands also are discussed. Our calculations reveal that the all-angle negative phenomena can be observed in the first two TM bands, and the frequency range of all-angle negative refraction can be tuned by changing plasma frequency. Those properties can be used to design the optical switching and sensor.

Band gap extension in honeycomb lattice two-dimensional plasma photonic crystals in the presence of dissipation

We investigate two types of honeycomb lattice two-dimensional plasma photonic crystals that possess large photonic band gaps in the presence of dissipation. We obtain a clear insight into the band structures and find imaginary parts of the eigenvalue band structure at the symmetry points display discontinuous behaviour when the filling factor of plasma in type-1 structure is low. Further more, we show how the photonic band gaps are affected by the normalized plasma frequency, radius of cylinder, dielectric constant and collision frequency. Our results demonstrate the band gap extension by increasing normalized plasma frequency in both type structures and radius of plasma cylinders in type-1 structure. The width of band gaps could also be enlarged by decreasing dielectric cylinder's radius. The bands shift toward lower frequencies when relative dielectric constant increases in both two types. These results may provide theoretical instructions to design new optoelectronic devices.

Properties of the band gap of two-dimensional plasma photonic crystals

Employing the finite-difference time-domain (FDTD) method, we study the filtering properties of twodimensional plasma photonic crystals. We show that the transmission spectra of the defects in the plasma photonic crystals vary with change in the defect location, its radius, the plasma frequency, and the frequency of electron–ion collisions in the plasma. We demonstrate that the two-dimensional defect structure from the viewpoint of its frequency characteristic (such as an adjustable filter characteristic) is similar to the one-dimensional structure. We find that by changing the parameters of the defect location, the plasma frequency, and the frequency of electron–ion collisions in the plasma, one can obtain different ranges of transmission peaks at different frequencies, which fully reflects the adjustable filter characteristics of the structure. Therefore, the two-dimensional structure is more important than the one-dimensional structure, and it can be used to produce actual microwave devices.