Reconfigurable plasma photonic crystals from triangular lattice to square lattice in dielectric barrier discharge

Highlights

• We demonstrate a flexible experimental method to realize fast reconfiguration of different plasma photonic crystals.

• Reconfigurable plasma photonic crystals whose symmetry and lattice constant can both be dynamically controlled are realized.

• A phenomenological reaction-diffusion model is established to simulate the formation of plasma structures.

• The band diagrams of different plasma photonic crystals are studied by use of finite element method.

Abstract

We demonstrate a flexible experimental method to realize fast reconfiguration of plasma photonic crystals by self-organization of filaments in dielectric barrier discharge (DBD). The symmetry and lattice constant of plasma photonic crystals can both be dynamically tuned by simply changing the applied voltage. The reconfiguration from a triangular lattice to a square lattice is realized and the triangular lattices with different lattice constants are also obtained. A phenomenological reaction-diffusion model of two interacting layers is established to simulate the formation of different plasma structures. Experimental observations and numerical simulation are in good agreement. Moreover, the band diagrams of different plasma photonic crystals have been studied by use of finite element method. It is shown that the positions and sizes of the band gaps change significantly when the configurations of plasma photonic crystals have been changed. Such plasma structures can be used as potential tunable metamaterials, which may find wide applications in the manipulation of microwaves and terahertz waves.

Introduction

The last few years have witnessed an ongoing search for photonic crystals (PCs) which typically exhibits a forbidden bandgap analogous to a semiconductor material [1], [2]. It is a kind of promising metamaterial that could alter radiation-matter interactions and significantly improve the efficiency of optical devices. Based on its superior optical features, the photonic crystals have been widely used to manipulate electromagnetic waves in applications such as wave filters, high-performance mirrors, optical wave guides, couplers and optical switches [3], [4], [5], [6], [7], [8]. Generally, the photonic crystal's properties are not changed due to their static structure once they are fabricated. How to achieve reconfigurability, allowing for real-time and on-demand control of the photonic bands, is one of the most attractive issues in this field. Different proposals to make tunable PCs via mechanical, thermal, biological, and opto-fluidic methods have been suggested [9], [10], [11], [12]. Recently there appears great interest in plasma photonic crystals (PPCs), which incorporates plasmas within the volume of the PCs [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26]. The plasma dispersive properties and active temporal switching capabilities bring about many new features for PPCs, such as the good tunability and the time-varying bandgaps. The dielectric constant of plasmas can be adjusted from strongly negative to positive values of less than unity by changing the electromagnetic (EM) wave frequency and electron density. The temporal behavior of the plasma photonic crystals can also be controlled dynamically by switching on/off or modulating the frequency of the driving sources [20], [21]. These tunable responses lead to stirring potential in applications such as the plasma lens, plasma antenna and plasmas stealth aircraft [4], [18].

To date, great efforts have been made in both experimental and numerical studies on PPCs [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31]. In experiment, O. Sakai et al. obtained a square PPC by using a metal array electrode [17]. Wang et al. realized tunable PPCs by arranging the discharge columns into a quadrilateral array [18]. Ouyang et al. utilized an array of discharge tubes to generate one-dimensional (1D) PPCs [19]. Gregório et al. presented a resonant photonic crystal for which transmission is time-modulated by self-initiated gaseous plasmas [20]. Chaudhari et al. suggested a kind of plasma metallic photonic crystals (PMPC) by inserting a periodic arrangement of metal rods into the plasma background [21]. Tan et al. obtained 1D PPC which is a periodic array of quartz discharge tubes in air [22]. Elsayed et al. proposed a novel type of PPC that consists of plasma and nanocomposite layers arranged in a Fibonacci sequence [23]. Sun et al. suggested a class of 3D photonic crystals comprising planar arrays of low-temperature plasma microcolumns embedded within a polymer/metal/dielectric scaffold [26]. In these studies, the tunable responses of PPCs are normally achieved by changing the plasma density or the lattice constant of the plasma crystals [17], [18], [19], [20], [21], [22], [23]. Despite promising progress they have made, it is still a significant challenge to tune the symmetries of structures flexibly, once the PPCs have been fabricated. Developing plasma photonic crystals whose symmetries and lattice constant can both be fast and deliberately controlled remains an open question, which can provide additional tunability and bring about more promising applications.

In this work, we present a kind of reconfigurable plasma photonic crystals whose symmetry and lattice constant can both be dynamically controlled by self-organization of plasma filaments in DBD. By simply varying the applied voltage, the plasma lattice structures can be tuned from a triangular lattice to a square lattice. The triangular lattices with different lattice constants are also realized. Based on the experimental results, a phenomenological reaction-diffusion model of two interacting layers is established to simulate the formation of different plasma structures. The simulation results are well consistent with the experimental observations. Moreover, the band diagrams of PPCs under a transverse-magnetic (TM) wave have been studied. The changes of the position and sizes of the band gaps with reconstruction of different PPCs are demonstrated.