Enhancement of efficiency on PancharatnamBerry geometric phase metalens in terahertz region

2021 ◽  
Author(s):  
Peng Chen ◽  
Bo Fang ◽  
Jianmin Li ◽  
Xu Jing ◽  
Ming Kong ◽  
...  
Keyword(s):  
Geometric Phase ◽  
Terahertz Region

scholarly journals Geometric phase for multidimensional manipulation of photonics spin Hall effect and helicity-dependent imaging

Nanophotonics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1501-1508 ◽  
Author(s):  
XiaoFei Zang ◽  
BingShuang Yao ◽  
Zhen Li ◽  
Yang Zhu ◽  
JingYa Xie ◽  
...  
Keyword(s):  
Hall Effect ◽  
Geometric Phase ◽  
Electromagnetic Waves ◽  
Spin Hall Effect ◽  
Spin States ◽  
Terahertz Waves ◽  
Circularly Polarized ◽  
Left Hand ◽  
Terahertz Region ◽  
Spin Orbit Interactions

AbstractThe spin Hall effect of light, associated with spin-orbit interactions, describes a transport phenomenon with optical spin-dependent splitting, leading to a plethora of applications such as sensing, imaging, and spin-controlled nanophotonics. Although geometric meatsurfaces can mimic photonic spin Hall effect by spatially splitting left-hand circularly polarized and right-hand circularly polarized states of electromagnetic waves with anomalous refraction or reflection angles, the geometric phase generated by metasurfaces hinders metalenses to realize simultaneous focusing of different spin states, limiting further applications. Here, we propose and experimentally demonstrate an approach to realizing a spin Hall metalens that can focus terahertz waves with different spin states and flexibly manipulate spin-dependent focal points in multiple spatial dimensions based on a pure geometric phase. A dielectric metasurface consisting of micropillars with identical shape and different in-plane orientations is designed to realize the multidimensional manipulation of photonics spin Hall effect in terahertz region. Furthermore, helicity-dependent imaging is demonstrated by the terahertz spin Hall metalens. The uniqueness and robust approach for manipulating spin photons may have a significant impact on designing ultra-compact and multifunctional devices and spin photonics devices.

Local Lattice Strain Measurement Using Geometric Phase Analysis of Dark Field Images from Scanning Transmission Electron Microscopy

2011 ◽  
Author(s):  
Jayhoon Chung ◽  
Guoda Lian ◽  
Lew Rabenberg
Keyword(s):  
Phase Analysis ◽  
Geometric Phase ◽  
Process Development ◽  
Local Strain ◽  
Strain Engineering ◽  
Dark Field ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Geometric Phase Analysis ◽  
Scanning Transmission

Abstract Since strain engineering plays a key role in semiconductor technology development, a reliable and reproducible technique to measure local strain in devices is necessary for process development and failure analysis. In this paper, geometric phase analysis of high angle annular dark field - scanning transmission electron microscope images is presented as an effective technique to measure local strains in the current node of Si based transistors.

scholarly journals Recent Progress in the Development of Graphene Detector for Terahertz Detection

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 4987
Author(s):  
Jianlong Liu ◽  
Xin Li ◽  
Ruirui Jiang ◽  
Kaiqiang Yang ◽  
Jing Zhao ◽  
...  
Keyword(s):  
Recent Progress ◽  
Photovoltaic Effect ◽  
Dimensional Structure ◽  
High Electron ◽  
Terahertz Waves ◽  
Terahertz Detectors ◽  
Basic Part ◽  
Suitable Material ◽  
Terahertz Region ◽  
Frequency Independent

Terahertz waves are expected to be used in next-generation communications, detection, and other fields due to their unique characteristics. As a basic part of the terahertz application system, the terahertz detector plays a key role in terahertz technology. Due to the two-dimensional structure, graphene has unique characteristics features, such as exceptionally high electron mobility, zero band-gap, and frequency-independent spectral absorption, particularly in the terahertz region, making it a suitable material for terahertz detectors. In this review, the recent progress of graphene terahertz detectors related to photovoltaic effect (PV), photothermoelectric effect (PTE), bolometric effect, and plasma wave resonance are introduced and discussed.

scholarly journals Theoretical Analysis of Terahertz Dielectric–Loaded Graphene Waveguide

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 210
Author(s):  
Da Teng ◽  
Kai Wang
Keyword(s):  
Photonic Devices ◽  
Effective Index ◽  
The Finite Element Method ◽  
Index Method ◽  
Modal Properties ◽  
Terahertz Region ◽  
Effective Index Method ◽  
Integration Density ◽  
Device Integration ◽  
Potential Applications

The waveguiding of terahertz surface plasmons by a GaAs strip-loaded graphene waveguide is investigated based on the effective-index method and the finite element method. Modal properties of the effective mode index, modal loss, and cut-off characteristics of higher order modes are investigated. By modulating the Fermi level, the modal properties of the fundamental mode could be adjusted. The accuracy of the effective-index method is verified by a comparison between the analytical results and numerical simulations. Besides the modal properties, the crosstalk between the adjacent waveguides, which determines the device integration density, is studied. The findings show that the effective-index method is highly valid for analyzing dielectric-loaded graphene plasmon waveguides in the terahertz region and may have potential applications in subwavelength tunable integrated photonic devices.

scholarly journals Highly Birefringent, Low Flattened Dispersion Photonic Crystal Fiber in the Terahertz Region

2021 ◽  
Vol 13 (2) ◽  
pp. 1-10
Author(s):  
Biao Wang ◽  
Chunrong Jia ◽  
Jiantan Yang ◽  
Zhigang Di ◽  
Jianquan Yao ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Crystal Fiber ◽  
Terahertz Region

scholarly journals Lateral PbS Photovoltaic Devices for High Performance Infrared and Terahertz Photodetectors

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1692
Author(s):  
Emmanuel K. Ampadu ◽  
Jungdong Kim ◽  
Eunsoon Oh
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Photovoltaic Device ◽  
Photovoltaic Devices ◽  
Temperature Spectrum ◽  
Terahertz Region ◽  
Room Temperature Spectrum ◽  
Ftir Spectrometer ◽  
Titanium Substrates ◽  
Deposition Conditions

We fabricated a lateral photovoltaic device for use as infrared to terahertz (THz) detectors by chemically depositing PbS films on titanium substrates. We discussed the material properties of PbS films grown on glass with varying deposition conditions. PbS was deposited on Ti substrates and by taking advantage of the Ti/PbS Schottky junction, we discussed the photocurrent transients as well as the room temperature spectrum response measured by Fourier transform infrared (FTIR) spectrometer. Our photovoltaic PbS device operates at room temperature for wavelength ranges up to 50 µm, which is in the terahertz region, making the device highly applicable in many fields.

Ultraviolet wavefront manipulation using topological insulator metasurfaces based on geometric phase

2021 ◽  
Vol 487 ◽  
pp. 126812
Author(s):  
Mingli Wan ◽  
Pengfei Ji ◽  
Rongrong Wang ◽  
Xiaopeng Zhang ◽  
Mingli Tian ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Geometric Phase

GEOMETRIC PHASE AND DISENTANGLEMENT OF A MOVING FOUR-LEVEL ATOM IN THE PRESENCE OF NONLINEAR MEDIUM

2012 ◽  
Vol 10 (01) ◽  
pp. 1250007 ◽  
Author(s):  
NOUR ZIDAN ◽  
S. ABDEL-KHALEK ◽  
M. ABDEL-ATY
Keyword(s):  
System Dynamics ◽  
Geometric Phase ◽  
Nonlinear Medium ◽  
Atomic Motion ◽  
Kerr Medium ◽  
Mode Structure ◽  
Field Mode ◽  
Level Atom

In this paper, we investigate the geometric phase of the field interacting with a moving four-level atom in the presence of Kerr medium. The results show that the atomic motion, the field-mode structure and Kerr medium play important roles in the evolution of the system dynamics. As illustration, we examine the behavior of the geometric phase and entanglement with experimentally accessible parameters. Some new aspects are observed and discussed.

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