All-angle negative refraction without negative effective index

Analysis of Self-Collimation Based Cavity Resonator Formed by Photonic Crystal

“…This self-collimating frequency region is entirely lies within the first band as shown in the Figure 1(a), which asserts the condition of single beam propagation given in Ref. [3] by ω ≤ 0.5( 2πc as ) ('a s ' is the surface period of the PC). For this corresponding frequency, the total reflection of selfcollimated beams at the truncated surface of the photonic prism is given through finite-element methodology [11].…”

“…In particular, the two main branches of the anomalous dispersion in photonic crystals consisting of flat dispersion regime (results in self-collimation) [2] and convex/concave shaped dispersion regime (results in all angle negative refraction) [3] offer novel photonic elements like sharp bends [4], beam splitters [5] and sub-wavelength imaging lens [6], open cavities [7,8] respectively. Among these, PCs are given much attention for the confinement of electromagnetic waves and localization of photons in the form of realization of cavity resonating structures [7][8][9].…”

Near Field Focusing Effect and Hyperbolic Dispersion in Dielectric Photonic Crystals

“…However, for a photonic crystal, the concept of flat lens imaging is not only addressed from negative refraction [11] but also from other approaches such as an anisotropic effect [12], partial band gaps [13][14][15], diffractive effects [16], the role of reflection [17], the effect of channeling from self-collimation [18,19] and on the existence of surface modes [20] etc..…”

“…Namely, the metamaterial [4,5], photonic crystal [6], and an indefinite medium (whose permittivity and permeability tensors do not have same sign) [7][8][9][10]. The mechanism of flat lens imaging is accounted from negative refraction, in which a flat slab can be able to focus near fields with sub-wavelength features.However, for a photonic crystal, the concept of flat lens imaging is not only addressed from negative refraction [11] but also from other approaches such as an anisotropic effect [12], partial band gaps [13][14][15], diffractive effects [16], the role of reflection [17], the effect of channeling from self-collimation [18,19] and on the existence of surface modes [20] etc..With respect to the existing approaches, this work attempts to understand the near field focusing behavior (Figure 1) at the operating …”

Super-Resolution Imaging of the Graded Photonic Crystal With Negative Refraction

“…But at the optical region, it seems very difficult to make such metallic structures. However, in optical region, it has been shown that two-dimensional photonic crystals (2D PC) can act as effective media with a negative effective refractive index in some frequency regions if being properly designed [7][8][9][10][11][12][13]. Luo et al [8] have studied all-angle negative refraction (AANR) effect in 2D PC that does not employ a negative effective index of refraction.…”