When we form a structure of plasmas distributed in a certain space in which electromagnetic waves propagate, such a plasma structure serves as a different medium from a homogeneous bulk plasma. We can also enhance or generate novel functions of the plasmas when we add other structural materials such as functional components. That is to say, when we estimate such a medium from the material properties such as permittivity, permeability and conductivity, it shows extraordinary and/or functional effects that arise from the synthesis of the structure. We call such an artificial material a plasma metamaterial. In this review, starting from a fundamental understanding of electromagnetic wave propagation in and around plasmas, we review the new functions of plasmas as metamaterials, including a photonic-crystal-like behavior, a negative refractive index state and a nonlinear bifurcated electric response, by describing specific plasma structures. In addition, we survey some specific applications of such media and predict a feasible scientific expansion of this field in the near future.

https://iopscience.iop.org/article/10.1088/0963-0252/21/1/013001/pdf

Plasmas as metamaterials: a review

In this paper, we demonstrate by theoretical analysis a novel way to enhance the omnidirectional photonic band gap (OBG) in a type of photonic structure made of dielectric and plasma one-dimensional (1D) photonic crystals (1D PCs) by introducing a matching layer. Simulations by the transfer matrix method (TMM) show that such an OBG is insensitive to the incident angle and the polarization of electromagnetic (EM) wave; the frequency range and central frequency of OBG are significantly enlarged by introducing a matching layer in the heterostructure compared to 1D conventional binary dielectric photonic crystals (DPCs). The photonic band gap (PBG) of both polarizations also can be obviously enlarged as the incident angle is relatively small. The OBG originates from a Bragg gap in contrast to zero-n gap or single negative (negative permittivity or negative permeability) gap. From the numerical results, it has been shown that introducing a matching layer in such a heterostructure has a superior feature in the...

Enhancement of omnidirectional photonic band gaps in one-dimensional dielectric plasma photonic crystals with a matching layer

Comparing with an all-dielectric binary photonic crystal, we show, in this work, that the photonic band gap in ternary metal- dielectric photonic crystal can be signiflcantly enlarged. First, the band gap enlargement due to the addition of the metallic fllm is examined in the case of normal incidence. Next, in the oblique incidence, a wider omnidirectional band gap can be obtained in such a ternary metal-dielectric photonic crystal. All the theoretical analyses are made based on the transfer matrix method together with the Drude model of metals.

/pdf/band-gap-extension-in-a-one-dimensional-ternary-metal-4859hzor5q.pdf

Band Gap Extension in a One-Dimensional Ternary Metal-Dielectric Photonic Crystal

A novel tunable filter featuring the defect mode of the TE wave from one-dimensional photonic crystals doped by magnetized plasma is presented. The photonic crystals are composed by SiO2 and air with one defect layer made by magnetized plasma. By the transfer matrix method and Bloch’s theorem, we find out that the frequency of the defect mode can be modulated by plasma density or external magnetic field. Without changing the structure of the photonic crystal, the defect mode can be modulated in a larger frequency range, especially when the left-hand polarized electromagnetic wave is utilized.

A novel tunable filter featuring defect mode of the TE wave from one-dimensional photonic crystals doped by magnetized plasma

Research in recent years has greatly advanced the understanding and capabilities of multi-beam interference (MBI). With this technology it is now possible to generate a wide range of one-, two-, and three-dimensional periodic optical-intensity distributions at the micro- and nano-scale over a large length/area/volume. These patterns may be used directly or recorded in photo-sensitive materials using multi-beam interference lithography (MBIL) to accomplish subwavelength patterning. Advances in MBI and MBIL and a very wide range of applications areas including nano-electronics, photonic crystals, metamaterials, subwavelength structures, optical trapping, and biomedical structures are reviewed and put into a unified perspective.

https://www.mdpi.com/2072-666X/2/2/221/pdf

Multi-Beam Interference Advances and Applications: Nano-Electronics, Photonic Crystals, Metamaterials, Subwavelength Structures, Optical Trapping, and Biomedical Structures

Properties of obliquely incident electromagnetic wave in one-dimensional (1D) magnetized plasma photonic crystals (PPCs) are studied in this paper. Based on the continuous boundary condition of electromagnetic wave in 1D PPC, transfer matrix equation and dispersion equation of transverse magnetic polarization are deduced, and the properties of dispersion and transmission relation in terms of external magnetic field, collision frequency, and dielectric constant of dielectric and incident angles are investigated, respectively. Results show that gap location and gap width can be effectively controlled by adjusting external magnetic field as well as incident angle, and increasing collision frequency has little effect on gap width while larger dielectric constant of dielectric leads to more gaps.

Properties of obliquely incident electromagnetic wave in one-dimensional magnetized plasma photonic crystals

A slow wave structure consisting of metallic photonic band gap cells for a Ka-band Cherenkov device is proposed in this paper. Attributing to the mode selectivity of the photonic band gap, only the TM01-like mode among the TM0n-like modes exists in such a slow wave structure. The dispersion characteristics of the slow wave structure are investigated by simulation and experiment. It is shown that the dispersion curve obtained from the experiment is in agreement with that from simulation.

Dispersion characteristics of a slow wave structure with metal photonic band gap cells

This paper presents a two-section model to produce beam bunching and obtain coherent Terahertz (THz) Smith–Purcell (SP) radiation. Based on the mechanism of the Cherenkov oscillator, a continuous beam is bunched in the first section without external signal. In the second section, the coherent THz-SP radiation is stimulated by the bunched beam interacting with open grating. The Particle-In-Cell (PIC) simulations show that the beam is effectively bunched and the strongest radiation is observed at 51° with the frequency of 194 GHz in this scheme.

Coherent Terahertz Smith-Purcell radiation from a two-section model

This paper presents a possible method to produce beam bunching and obtain coherent Terahertz (THz) Smith–Purcell (SP) radiation. A model of two-section rectangular grating is proposed. In the first section with a flat conducting roof, a continuous beam is bunched by using an 88.5 GHz input signal. In the second section without metal roof, the coherent THz SP radiation is stimulated by the bunched beam interacting with the grating. The particle-in-cell (PIC) simulations show that the beam is bunched at the downstream of the first section. The strongest radiation is observed at 120° with the frequency of 266.5 GHz in the second section.

Coherent Terahertz Smith Purcell radiation from beam bunching

The relative band gap for a rhombus lattice photonic crystal is studied by plane wave expansion method and high frequency structure simulator (HFSS) simulation. General wave vectors in the first Briliouin zone are derived. The relative band gap as a function of air-filling factor and background material is investigated, respectively, and the nature of photonic band gap for different lattice angles is analyzed by the distribution of electric energy. These results would provide theoretical instruction for designing optical integrated devices using photonic crystal with a rhombus lattice.

Xi Gao

Papers

Properties of obliquely incident electromagnetic wave in one-dimensional magnetized plasma photonic crystals

Dispersion characteristics of a slow wave structure with metal photonic band gap cells

Coherent Terahertz Smith-Purcell radiation from a two-section model

Coherent Terahertz Smith Purcell radiation from beam bunching

Analysis of two-dimensional photonic band gap structure with a rhombus lattice