Near?Zero Index Photonic Crystals with Directive Bound States in the Continuum

Anisotropy-Induced Photonic Bound States in the Continuum

Topologically protected bound states in photonic parity-time-symmetric crystals.

Parity-time (PT)-symmetric crystals are a class of non-Hermitian systems that allow, for example, the existence of modes with real propagation constants, for self-orthogonality of propagating modes, and for uni-directional invisibility at defects. Photonic PT-symmetric systems that also support topological states could be useful for shaping and routing light waves. However, it is currently deba...

Optical Refractive Index Sensing Based on High-Q Bound States in the Continuum in Free-Space Coupled Photonic Crystal Slabs

High sensitivity (S) and high quality factor (Q) are desirable to achieve low detection limit in label-free optical sensors. In this paper, we theoretically demonstrate that single-layer and coupled bi-layer photonic crystal slabs (PCS) possess simultaneously high S and high Q near the bound states in the continuum (BIC). We theoretically achieved S > 800 nm/RIU and Q > 10⁷ in refractive index ...

Studying Focusing Properties of Graded Index Photonic Crystals Made of Material with Different Refractive Index

In this paper we investigate focusing properties of graded index (GRIN) photonic crystal (PC) structures which are composed of different materials with different refractive indices. GRIN PC structure is constructed from air holes in dielectric background. The holes radii are varied in the normal direction to the propagation in such a way that a parabolic effective refractive index is produced. ...

Surface states in photonic crystals

The propagation of surface electromagnetic waves along photonic crystal (PC) boundaries is examined. It is shown that in a number of cases, these are backward waves. The nature of surface electromagnetic states localized at the PC boundary is discussed; these states transfer no energy along the boundary (their tangential wave number is zero). An analogy with the well-known Tamm and Shockley sur...