Self‐Collimation in Photonic Crystals: Applications and Opportunities

Abstract

A comprehensive review considering recent advances in self-collimation and its applications in optical integration is covered in the current article. Self-collimation is compared to the conventional technique of photonic bandgap engineering to control the light propagation in photonic crystal-based structures. It is fully discussed how the self-collimation phenomenon can be tailored to be independent of the incident angle and polarization. This adds substantial flexibility to the structure to overcome light coupling challenges and simultaneously aids in the omission of bulk and challenging elements, including polarizers and lenses from optical integrated circuits. Additionally, designed structures have the potential to be rescaled to operate in any desired frequency range thanks to the scalability rule in the field of electromagnetics. Moreover, it is shown that one can boost the coupling efficiency by applying an anti-reflection property to the structure, which provides not only efficient index matching but also the matching between external waves with uniform amplitude and Bloch waves with periodic amplitude.

Self‐Collimation and Slow Light‐Based Refractive Index Sensor with a Large Detection Range

“…[ 1 ] PCs are periodic arrangements of macroscopic dielectric materials that provide photonic bandgap (PBG) characteristics besides various dispersion anomalies leading to super‐prism, negative refraction, slow light, and self‐collimation (SC) phenomena. [ 2–4 ] So far, interesting and highly efficient devices based on PCs have been reported in sensing, imaging, cloaking and invisibility, and energy harvesting. [ 5–8 ] One of the major fields of applications is devoted to sensor design by PCs and diverse sensors have been reported for temperature, pressure, pH, humidity, and refractive index (RI) which find potential applications in healthcare, automation, defense, security, food quality control, and environment.…”

“…The other phenomenon in PCs which provides diffraction‐less propagation of light and eases the fabrication process besides the omission of extra need for bulky lenses and polarizers is SC process. [ 4 ] The first specialized investigation of self‐collimation has been carried out by Kasaka et.al, [ 29 ] followed by theoretical and experimental studies of in‐band characteristics in PCs. [ 30,31 ] The numerical and analytical investigation on higher‐order diffraction elimination which results in SC, has been proposed in.…”

All‐Angle Self‐Collimation‐Based Invisibility Cloaking in 2D Square Lattice Photonic Crystals

“…Self‐collimation (SC) in PhCs is an in‐band phenomenon that assists diffraction‐less propagation of light by dispersion management. [ 8 ] In the self‐collimating PhCs, the wavefront moves in a unique direction inside the structure determined by the orientation of the group velocity ( v g ), unless some modifications are applied. The direction of the group velocity in PhC is determined by equal frequency contours (EFCs) according to the relation, ( v g = Δ k ω ( k ), where ω corresponds to the frequency with wave vector ( k ).…”

A Highly Accurate Refractive Index Sensor with Two Operation Modes Based on Photonic Crystal Ring Resonator

“…Photonic crystals (PCs) which are periodic arrangements of macroscopic dielectric materials possess anomalous properties such as photonic band gaps (PBGs), super‐prism, self‐collimation, slow light, and negative refraction . PCs have been extensively studied since they were first introduced by Yablonovitch and John .…”