Slow wave resonance in periodic stacks of anisotropic layers

TL;DR

This paper explores how to achieve perfect impedance matching in birefringent layered structures with degenerate photonic band edges, enabling polarization-independent giant transmission resonances for advanced photonic applications.

Contribution

It introduces a modification to layered stacks that ensures polarization independence while maintaining high-Q resonances at degenerate photonic band edges.

Findings

Achieves polarization-independent impedance matching in birefringent stacks.

Maintains giant transmission resonance at degenerate band edges.

Enhances practical applications like filters and antennas.

Abstract

We consider transmission band edge resonance in periodic layered structures involving birefringent layers. Previously we have shown that the presence of birefringent layers with misaligned in-plane anisotropy can dramatically enhance the performance of the photonic-crystal Fabry-Perot resonator. It allows to reduce its size by an order of magnitude without compromising on its performance. The key characteristic of the enhanced photonic-crystal cavity is that its Bloch dispersion relation displays a degenerate photonic band edge, rather than only regular ones. This can be realized in specially arranged stacks of misaligned anisotropic layers. On the down side, the presence of birefringent layers results in the Fabry-Perot resonance being coupled only with one (elliptic) polarization component of the incident wave, while the other polarization component is reflected back to space. In this paper we show how a small modification of the periodic layered array can solve the above fundamental problem and provide a perfect impedance match regardless of the incident wave polarization, while preserving the giant transmission resonance, characteristic of a degenerate photonic band edge. Both features are of critical importance for a variety of practical applications, including antennas, light amplification, optical and microwave filters, etc.