scholarly journals Group Velocity Modulation and Light Field Focusing of the Edge States in Chirped Valley Graphene Plasmonic Metamaterials

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1808
Author(s):  
Liqiang Zhuo ◽  
Huiru He ◽  
Ruimin Huang ◽  
Shaojian Su ◽  
Zhili Lin ◽  
...  
Keyword(s):  
Group Velocity ◽  
Light Field ◽  
Slow Light ◽  
Dielectric Materials ◽  
Degree Of Freedom ◽  
Geometrical Parameters ◽  
Edge States ◽  
Velocity Modulation ◽  
Plasmonic Metamaterials ◽  
On Chip

The valley degree of freedom, like the spin degree of freedom in spintronics, is regarded as a new information carrier, promoting the emerging valley photonics. Although there exist topologically protected valley edge states which are immune to optical backscattering caused by defects and sharp edges at the inverse valley Hall phase interfaces composed of ordinary optical dielectric materials, the dispersion and the frequency range of the edge states cannot be tuned once the geometrical parameters of the materials are determined. In this paper, we propose a chirped valley graphene plasmonic metamaterial waveguide composed of the valley graphene plasmonic metamaterials (VGPMs) with regularly varying chemical potentials while keeping the geometrical parameters constant. Due to the excellent tunability of graphene, the proposed waveguide supports group velocity modulation and zero group velocity of the edge states, where the light field of different frequencies focuses at different specific locations. The proposed structures may find significant applications in the fields of slow light, micro–nano-optics, topological plasmonics, and on-chip light manipulation.

Slow Light in Vertically Coupled Resonator of Conical Rod Portion

2011 ◽  
Vol 403-408 ◽  
pp. 43-47
Author(s):  
Nor Ain Husein ◽  
Saktioto ◽  
Zulfadzli Yusoff ◽  
Jalil Ali
Keyword(s):  
Group Velocity ◽  
Slow Light ◽  
Geometrical Parameters ◽  
Velocity Of Light ◽  
Optical Buffering ◽  
Conical Rod ◽  
Coupled Resonator

Resonator structures have been proposed and modified as a method of reducing the group velocity of light for optical buffering in telecommunication field. This makes the characterization and optimization of the method become important to apply. In this paper, the characterization of vertically coupler resonator is modified by investigating its geometrical parameters. The modified models with conical rod portion as the slow light structure is described where the group velocity parameters are varied. The results found that the separation gap between fibers, lg and the rod radius, a are significant in reducing the group velocity of light through such a system in the case of lossless resonators.

scholarly journals Double-layer graphene on photonic crystal waveguide electro-absorption modulator with 12 GHz bandwidth

Nanophotonics ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 2377-2385 ◽  
Author(s):  
Zhao Cheng ◽  
Xiaolong Zhu ◽  
Michael Galili ◽  
Lars Hagedorn Frandsen ◽  
Hao Hu ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Double Layer ◽  
Slow Light ◽  
Modulation Depth ◽  
Photonic Crystal Waveguide ◽  
Optical Modulators ◽  
Layer Graphene ◽  
Silicon Photonic ◽  
On Chip ◽  
Silicon Based

AbstractGraphene has been widely used in silicon-based optical modulators for its ultra-broadband light absorption and ultrafast optoelectronic response. By incorporating graphene and slow-light silicon photonic crystal waveguide (PhCW), here we propose and experimentally demonstrate a unique double-layer graphene electro-absorption modulator in telecommunication applications. The modulator exhibits a modulation depth of 0.5 dB/μm with a bandwidth of 13.6 GHz, while graphene coverage length is only 1.2 μm in simulations. We also fabricated the graphene modulator on silicon platform, and the device achieved a modulation bandwidth at 12 GHz. The proposed graphene-PhCW modulator may have potentials in the applications of on-chip interconnections.

scholarly journals Towards lab-on-chip ultrasensitive ethanol detection using photonic crystal waveguide operating in the mid infrared

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Rostamian ◽  
Ehsan Madadi-Kandjani ◽  
Hamed Dalir ◽  
Volker J. Sorger ◽  
Ray T. Chen
Keyword(s):  
Photonic Crystal ◽  
Slow Light ◽  
High Sensitivity ◽  
Guided Wave ◽  
Silicon On Insulator ◽  
Group Index ◽  
Photonic Crystal Waveguide ◽  
Mid Infrared ◽  
Lab On Chip ◽  
On Chip

Abstract Thanks to the unique molecular fingerprints in the mid-infrared spectral region, absorption spectroscopy in this regime has attracted widespread attention in recent years. Contrary to commercially available infrared spectrometers, which are limited by being bulky and cost-intensive, laboratory-on-chip infrared spectrometers can offer sensor advancements including raw sensing performance in addition to use such as enhanced portability. Several platforms have been proposed in the past for on-chip ethanol detection. However, selective sensing with high sensitivity at room temperature has remained a challenge. Here, we experimentally demonstrate an on-chip ethyl alcohol sensor based on a holey photonic crystal waveguide on silicon on insulator-based photonics sensing platform offering an enhanced photoabsorption thus improving sensitivity. This is achieved by designing and engineering an optical slow-light mode with a high group-index of n g  = 73 and a strong localization of modal power in analyte, enabled by the photonic crystal waveguide structure. This approach includes a codesign paradigm that uniquely features an increased effective path length traversed by the guided wave through the to-be-sensed gas analyte. This PIC-based lab-on-chip sensor is exemplary, spectrally designed to operate at the center wavelength of 3.4 μm to match the peak absorbance for ethanol. However, the slow-light enhancement concept is universal offering to cover a wide design-window and spectral ranges towards sensing a plurality of gas species. Using the holey photonic crystal waveguide, we demonstrate the capability of achieving parts per billion levels of gas detection precision. High sensitivity combined with tailorable spectral range along with a compact form-factor enables a new class of portable photonic sensor platforms when combined with integrated with quantum cascade laser and detectors.

On-chip discrimination of orbital angular momentum of light with plasmonic nanoslits

Nanoscale ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 2227-2233 ◽  
Author(s):  
Shengtao Mei ◽  
Kun Huang ◽  
Hong Liu ◽  
Fei Qin ◽  
Muhammad Q. Mehmood ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Communication ◽  
Communication System ◽  
Degree Of Freedom ◽  
System Capacity ◽  
Optical Communication System ◽  
On Chip

The orbital angular momentum (OAM) of light can be taken as an independent and orthogonal degree of freedom for multiplexing in an optical communication system, potentially improving the system capacity to hundreds of Tbits per second.

scholarly journals Slow light bimodal interferometry in one-dimensional photonic crystal waveguides

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Luis Torrijos-Morán ◽  
Amadeu Griol ◽  
Jaime García-Rupérez
Keyword(s):  
Photonic Crystal ◽  
Group Velocity ◽  
Communication Networks ◽  
Slow Light ◽  
Single Channel ◽  
Point Of Care ◽  
Semiconductor Industry ◽  
Optical Modulator ◽  
One Dimensional ◽  
Dimensional Photonic Crystal

AbstractStrongly influenced by the advances in the semiconductor industry, the miniaturization and integration of optical circuits into smaller devices has stimulated considerable research efforts in recent decades. Among other structures, integrated interferometers play a prominent role in the development of photonic devices for on-chip applications ranging from optical communication networks to point-of-care analysis instruments. However, it has been a long-standing challenge to design extremely short interferometer schemes, as long interaction lengths are typically required for a complete modulation transition. Several approaches, including novel materials or sophisticated configurations, have been proposed to overcome some of these size limitations but at the expense of increasing fabrication complexity and cost. Here, we demonstrate for the first time slow light bimodal interferometric behaviour in an integrated single-channel one-dimensional photonic crystal. The proposed structure supports two electromagnetic modes of the same polarization that exhibit a large group velocity difference. Specifically, an over 20-fold reduction in the higher-order-mode group velocity is experimentally shown on a straightforward all-dielectric bimodal structure, leading to a remarkable optical path reduction compared to other conventional interferometers. Moreover, we experimentally demonstrate the significant performance improvement provided by the proposed bimodal photonic crystal interferometer in the creation of an ultra-compact optical modulator and a highly sensitive photonic sensor.

scholarly journals Direct quantification of topological protection in symmetry-protected photonic edge states at telecom wavelengths

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Sonakshi Arora ◽  
Thomas Bauer ◽  
René Barczyk ◽  
Ewold Verhagen ◽  
L. Kuipers
Keyword(s):  
Near Field ◽  
Edge States ◽  
Quantum Networks ◽  
Hall Effects ◽  
Upper Limits ◽  
On Chip ◽  
Symmetry Protected ◽  
Topological Robustness ◽  
Direct Quantification ◽  
Sub Wavelength

AbstractTopological on-chip photonics based on tailored photonic crystals (PhCs) that emulate quantum valley-Hall effects has recently gained widespread interest owing to its promise of robust unidirectional transport of classical and quantum information. We present a direct quantitative evaluation of topological photonic edge eigenstates and their transport properties in the telecom wavelength range using phase-resolved near-field optical microscopy. Experimentally visualizing the detailed sub-wavelength structure of these modes propagating along the interface between two topologically non-trivial mirror-symmetric lattices allows us to map their dispersion relation and differentiate between the contributions of several higher-order Bloch harmonics. Selective probing of forward- and backward-propagating modes as defined by their phase velocities enables direct quantification of topological robustness. Studying near-field propagation in controlled defects allows us to extract upper limits of topological protection in on-chip photonic systems in comparison with conventional PhC waveguides. We find that protected edge states are two orders of magnitude more robust than modes of conventional PhC waveguides. This direct experimental quantification of topological robustness comprises a crucial step toward the application of topologically protected guiding in integrated photonics, allowing for unprecedented error-free photonic quantum networks.

Terahertz evanescent field microscopy of dielectric materials using on-chip waveguides

2008 ◽  
Vol 92 (3) ◽  
pp. 032903 ◽  
Author(s):  
J. Cunningham ◽  
M. Byrne ◽  
P. Upadhya ◽  
M. Lachab ◽  
E. H. Linfield ◽  
...  
Keyword(s):  
Dielectric Materials ◽  
Evanescent Field ◽  
On Chip

Electrochemically Prepared Pore Arrays for Photonic-Crystal Applications

MRS Bulletin ◽  
2001 ◽  
Vol 26 (8) ◽  
pp. 623-626 ◽  
Author(s):  
R.B. Wehrspohn ◽  
J. Schilling
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Electromagnetic Waves ◽  
Porous Alumina ◽  
Dielectric Materials ◽  
Dielectric Medium ◽  
Geometrical Parameters ◽  
Quarter Wavelength ◽  
Physically Based ◽  
1D Photonic Crystal

In the last few years, photonic crystals have gained considerable interest due to their ability to “mold the flow of light.” Photonic crystals are physically based on Bragg reflections of electromagnetic waves. In simple terms, a one-dimensional (1D) photonic crystal is a periodic stack of thin dielectric films with two different refractive indices, n1 and n2. The two important geometrical parameters determining the wavelength of the photonic bandgap are the lattice constant, a = d1(n1) + d2(n2), and the ratio of d1 to a (where d1 is the thickness of the layer with refractive index n1, and d2 is the thickness of layer n2). For a simple quarter-wavelength stack, the center wavelength λ of the 1D photonic crystal would be simply λ = 2n1d1 + 2n2d2. In the case of 2D photonic crystals, the concept is extended to either airholes in a dielectric medium or dielectric rods in air. Therefore, ordered porous dielectric materials like porous silicon or porous alumina are intrinsically 2D photonic crystals.

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