35 research outputs found
Modeling an Electrically Driven Graphene-Nanoribbon Laser for Optical Interconnects
Graphene has two very important optical properties of population inversion of
electrons, and broadband optical gain. As a result, graphene has potential for
use in lasers and amplifiers. In this work, we presented a quantum master model
and analyzed the properties for the electrically pumped single-AGNR
vertical-cavity surface-emitting lasers (VCSELs) to investigate the lasing
action and laser properties for realistic experimental parameters. A
semiclassical approximation for the output power and laser linewidth is also
derived. The laser threshold power was several orders of magnitude lower than
that currently achievable with semiconductor microlasers. Our results have
demonstrated that a single-AGNR VCSEL can serve as a nanolaser with ultralow
lasing threshold. Implementation of such a GNR-based VCSEL is especially
promising for optical interconnection systems since VCSELs emit low optical
power and single longitudinal mode over a wide wavelength spectral range
through tailoring GNRs.Comment: 5 pages, 4 figures,
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6458072&tag=
Prediction of Near-Room-Temperature Quantum Anomalous Hall Effect on Honeycomb Materials
Recently, this long-sought quantum anomalous Hall effect was realized in the
magnetic topological insulator. However, the requirement of an extremely low
temperature (approximately 30 mK) hinders realistic applications. Based on
\textit{ab-initio} band structure calculations, we propose a quantum anomalous
Hall platform with a large energy gap of 0.34 and 0.06 eV on honeycomb lattices
comprised of Sn and Ge, respectively. The ferromagnetic order forms in one
sublattice of the honeycomb structure by controlling the surface
functionalization rather than dilute magnetic doping, which is expected to be
visualized by spin polarized STM in experiment. Strong coupling between the
inherent QSH state and ferromagnetism results in considerable exchange
splitting and consequently an FM insulator with a large energy gap. The
estimated mean-field Curie temperature is 243 and 509 K for Sn and Ge lattices,
respectively. The large energy gap and high Curie temperature indicate the
feasibility of the QAH effect in the near-room-temperature and even
room-temperature regions.Comment: 6 pages, 4 figures and 1 tabl
An Efficient Method of Detection and Recognition in Remote Sensing Image Based on multi-angle Region of Interests
Presently, deep learning technology has been widely used in the field of
image recognition. However, it mainly aims at the recognition and detection of
ordinary pictures and common scenes. As special images, remote sensing images
have different shooting angles and shooting methods compared with ordinary
ones, which makes remote sensing images play an irreplaceable role in some
areas. In this paper, based on a deep convolution neural network for providing
multi-level information of images and combines RPN (Region Proposal Network)
for generating multi-angle ROIs (Region of Interest), a new model for object
detection and recognition in remote sensing images is proposed. In the
experiment, it achieves better results than traditional ways, which demonstrate
that the model proposed here would have a huge potential application in remote
sensing image recognition.Comment: 4 pages, 3 figure
Two-Dimensional Scanning Phased Array Based on Pattern Reconfigurable Antenna
This paper presents a novel planar phased array that can work in Ka band
designed for two-dimensional scanning. A four-modes pattern reconfigurable
element based on microstrip Yagi antenna is proposed, and then developed into
the 4X4 phased array, in which two feed points are introduced to reduce
sidelobe level (SLL). The simulated results show that our proposed phased array
is able to cover the scanning range from -60{\deg} to +60{\deg}in
H-plane(yoz-plane) and -47.2{\deg}to +47.2{\deg}in E-plane(xoz-plane) with the
gain reduction less than 3dB, both the SLLs of which are 10dB less than main
beam. The two-dimensional scanning phased array based on pattern reconfigurable
antenna (PRA) presented here is suitable for the satellite communication.Comment: 4 pages, 6 figure