Robust topological edge states from one-dimensional diatomic chain photonic crystals

2021 ◽  
pp. 2150146
Author(s):  
Yun-Tuan fang ◽  
Xiao-Xue Li ◽  
Li-Xia Yang
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Edge State ◽  
Unit Cell ◽  
Topological Phase ◽  
Edge States ◽  
One Dimensional ◽  
Diatomic Chain ◽  
Ssh Model ◽  
Unit Cell Length

The Su–Schrieffer–Heeger (SSH) model can occur in a one-dimensional (1D) diatomic chain photonic crystal (PC) in which a unit cell includes two same slabs (atoms). With different intervals of the two slabs, the two combined 1D PCs can support topological edge states in all photonic boundary bandgaps. These topological edge states come from the inversion of topological phase of the bands through the band folding effect. When the sum of the two atom intervals in the two different 1D PCs equals to the unit cell length, these edge state frequencies keep invariant.

scholarly journals Tailoring Topological Edge States with Photonic Crystal Nanobeam Cavities

2020 ◽  
Author(s):  
Yongkang Gong ◽  
Liang Guo ◽  
Stephan Wong ◽  
Anthony Bennett ◽  
Sang Soon Oh
Keyword(s):  
Photonic Crystal ◽  
Mode Coupling ◽  
Hole Array ◽  
Edge States ◽  
One Dimensional ◽  
Additional Degree ◽  
Wide Range ◽  
Nanobeam Cavities ◽  
Ssh Model ◽  
Significant Attention

Abstract The realization of topological edge states (TESs) in photonic systems has provided unprecedented opportunities for manipulating light in novel manners. The Su-Schrieffer Heeger (SSH) model has recently gained significant attention and has been exploited in a wide range of photonic platforms to create TESs. We develop a photonic topological insulator strategy based on SSH photonic crystal nanobeam cavities. In contrast to the conventional photonic SSH schemes which are based on alternately tuned coupling rength in one dimensional lattice, our proposal provides higher flexibility and allows tailoring TESs by manipulating mode coupling in a two-dimensional manner. We reveal that the proposed hole array based nanobeams in a dielectric membrane can selectively tailor single or double TESs in the telecommunication region by controlling the coupling strength of the adjacent SSH nanobeams in both vertical and horizontal directions. Our finding provides an additional degree of freedom in exploiting the SSH model for integrated topological hotonic devices and functionalities based on the well-established photonic crystal nanobeam cavity platforms.

scholarly journals Topological phase transition between a normal insulator and a topological metal state in a quasi-one-dimensional system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Milad Jangjan ◽  
Mir Vahid Hosseini
Keyword(s):  
Phase Transition ◽  
Dimensional System ◽  
Inversion Symmetry ◽  
Topological Phase ◽  
Edge States ◽  
Zero Energy ◽  
One Dimensional ◽  
Topological Phase Transition ◽  
Metal State ◽  
Topological Metal

AbstractWe theoretically report the finding of a new kind of topological phase transition between a normal insulator and a topological metal state where the closing-reopening of bandgap is accompanied by passing the Fermi level through an additional band. The resulting nontrivial topological metal phase is characterized by stable zero-energy localized edge states that exist within the full gapless bulk states. Such states living on a quasi-one-dimensional system with three sublattices per unit cell are protected by hidden inversion symmetry. While other required symmetries such as chiral, particle-hole, or full inversion symmetry are absent in the system.

Manipulation of thermal radiation by using photonic crystals

2021 ◽  
pp. 2150262
Author(s):  
Azka Umar ◽  
Chun Jiang
Keyword(s):  
Numerical Simulation ◽  
Refractive Index ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Thermal Emission ◽  
Heat Energy ◽  
Radiation Loss ◽  
One Dimensional ◽  
Waveguide Core ◽  
Low Refractive Index

This paper focuses on manipulating thermal emission and radiation loss of heat energy in a heat waveguide. A One-Dimensional Photonic Crystal is used as a waveguide clad to prohibit the thermal emission from escaping. The model may reduce the radiation loss of heat energy in the waveguide core, and heat energy can be confined to propagate along the waveguide’s longitude axis. The waveguide clad comprises alternative layers of high and low refractive index materials containing sufficient electromagnetic stop bands to trap the thermal emission from escaping out of the waveguide. The numerical simulation of the model shows that the forbidden bandgap of photonic crystal structures with alternative layers of silica and silicon has width enough to make heat energy be confined within the waveguide core so that efficient heat energy transmission can be achieved along the longitude axis of the waveguide.

Exciton Polaritons in One-Dimensional Metal-Semiconductor Photonic Crystals

2008 ◽  
Vol 8 (12) ◽  
pp. 6584-6588 ◽  
Author(s):  
R. Márquez-Islas ◽  
B. Flores-Desirena ◽  
F. Pérez-Rodríguez
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Band Structure ◽  
Dielectric Function ◽  
Low Frequency ◽  
Photonic Band Structure ◽  
One Dimensional ◽  
Exciton Polaritons ◽  
Metal Layers ◽  
Photonic Band

We investigate theoretically the coupling of exciton with light in a one-dimensional photonic crystal. The unit cell of the crystal consists of two alternating layers, namely a metallic layer and a semiconductor one. The frequency-dependent dielectric function of the metal is described by the Drude model, whereas for the semiconductor we use a nonlocal excitonic dielectric function. The polariton dispersion for s-polarized modes in the metal-semiconductor photonic crystal is compared with that for a dielectric-semiconductor photonic crystal. Because of the metal layers, a low-frequency gap appears in the photonic band structure. The presence of the semiconductor gives rise to photonic bands associated with the coupling of light with size-quantized excitón states. At frequencies above the longitudinal exciton frequency, the photonic band structure exhibits anticrossing phenomena produced by the upper exciton–polariton mode and size-quantized excitons. It is found that the anticrossing phenomena in the metal-semiconductor photonic crystal occur at higher frequencies in comparison with the dielectric-semiconductor case.

scholarly journals Natural slab photonic crystals in centric diatoms

2019 ◽  
Author(s):  
Johannes W. Goessling ◽  
William P. Wardley ◽  
Martin Lopez Garcia
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Spectral Range ◽  
Near Infrared ◽  
Light Regulation ◽  
Visible Spectral Range ◽  
Mating Strategies ◽  
Unit Cell ◽  
Critical Parameters ◽  
Centric Diatom

AbstractNatural photonic crystals can serve in mating strategies or as aposematism for animals, but they also exist in some photosynthetic organisms, with potential implications for their light regulation. Some of the most abundant microalgae, named diatoms, evolved a silicate exoskeleton, the frustule, perforated with ordered pores resembling photonic crystals. Here we present the first combined experimental and theoretical characterization of the photonic properties of the diatom girdle, i.e. one of two structures assembling the frustule. We show that the girdle of the centric diatom Coscinodiscus granii is a well-defined slab photonic crystal, causing, under more natural conditions when immersed in water, a pseudogap for modes in the near infrared. The pseudogap disperses towards the visible spectral range when light incides at larger angles. The girdle crystal structure facilitates in-plane propagation for modes in the green spectral range. We demonstrate that the period of the unit cell is one of the most critical factors for causing these properties. The period is shown to be similar within individuals of a long-term cultivated inbred line and between 4 different C. granii cell culture strains. In contrast, the pore diameter had negligible effects upon the photonic properties. We hence propose that critical parameters defining the photonic response of the girdle are highly preserved. Other centric diatom species, i.e. Thalasiosira pseudonana, C. radiatus and C. wailesii, present similar unit cell morphologies with various periods in their girdles. We speculate that evolution has preserved the photonic crystal character of the centric girdle, indicating an important biological functionality for this clade of diatoms.

scholarly journals Directional luminescence of the diamond NV center via Bloch surface waves in one-dimensional photonic crystals

2021 ◽  
Vol 2015 (1) ◽  
pp. 012022
Author(s):  
A A Bragina ◽  
K R Safronov ◽  
V O Bessonov ◽  
A A Fedyanin
Keyword(s):  
Angular Distribution ◽  
Photonic Crystal ◽  
Surface Wave ◽  
Photonic Crystals ◽  
Surface Waves ◽  
Coupling Efficiency ◽  
One Dimensional ◽  
Close Proximity ◽  
Nv Center ◽  
Bloch Surface Wave

Abstract In this work, we numerically study the luminescence of nanodiamonds with NV centres embedded in a polymer layer on the surface of one-dimensional photonic crystal. The interaction of NV center spontaneous emission with the Bloch surface wave (BSW) is demonstrated. The presence of a photonic crystal leads to a change in the angular distribution of the emitter radiation due to the coupling of luminescence to BSW. We show that the best coupling efficiency of 71% is observed when NV centres are located in the close proximity to the BSW field maximum.

Free-standing, flexible thermochromic films based on one-dimensional magnetic photonic crystals

2015 ◽  
Vol 3 (12) ◽  
pp. 2848-2855 ◽  
Author(s):  
Huiru Ma ◽  
Mingxing Zhu ◽  
Wei Luo ◽  
Wei Li ◽  
Kai Fang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Radical Polymerization ◽  
Free Standing ◽  
One Dimensional ◽  
Magnetic Photonic Crystals

Instant radical polymerization of sterically stabilized magnetically responsive photonic crystal nonaqueous suspensions under magnetic field can obtain flexible thermochromic free-standing films, which display bright iridescent colors strongly sensitive to temperature with good reversibility and durability.

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