ORCID Profile
0000-0002-8702-0121
Current Organisations
Tianjin University
,
Australian National University
,
Central South University
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Publisher: Walter de Gruyter GmbH
Date: 14-07-2022
Abstract: Vortex beams carrying orbital angular momentum (OAM) open a new perspective in various terahertz research. Multichannel and ergence controllable terahertz vortex beam generation holds the key to promoting the development of OAM related terahertz research. Here, we introduced and experimentally demonstrated quasi-perfect vortex beam (Q-PVB) with a controllable ergence angle independent of the topological charge and multichannel Q-PVBs generation with all-dielectric multifunctional metasurfaces. By superimposing specific phase functions together into the metasurfaces, multiple vortex beams and four-channel Q-PVBs with different topological charges are generated as well as focused at separated positions. High resolution characterization of terahertz electric field shows the good quality and broadband properties of Q-PVBs. Interestingly, compared with conventional perfect vortex beam Q-PVB displays a smaller ergence angle and thinner ring width. The metasurfaces proposed here provide a promising avenue to realize multichannel vortex beams generation in compact terahertz systems benefiting OAM related researches such as mode ision multiplexing, vortex beam related plasmonic enhancement and spinning objective detection.
Publisher: Wiley
Date: 30-07-2020
Publisher: American Physical Society (APS)
Date: 16-05-2023
Publisher: Springer Science and Business Media LLC
Date: 19-08-2019
Publisher: Jurnal Rekayasa Elektrika (JRE)
Date: 09-01-2020
Abstract: Quadruped robot is one of the types of robots that move using legs 4 compiled by some of the servo motor as a driving force on each foot ft the DOF is used. However, problems arise when this robot is confronted on the inclined plane, because the burden is borne out every servo motor on the feet will be different, so can make a fast servo motor damaged. This research was conducted on the design of the quadruped robot system for stability on the inclined plane using the accelerometer sensor and the application of the inverse kinematics method with PID control of Ziegler-Nichols. The results of tests obtained response robots in stabilizing the body when faced with the inclined plane with some degree of slope of the pitch and roll. In this research was conducted some test for quadruped robot: static Testing robot against the angel of the pitch in the standby retrieved response average robot in stabilizing the body is 245 ms, static Testing robot against the angle of roll in standby retrieved response average robot in stabilizing the body is 280 ms, dynamic Testing robot against the roll and pitch in standby retrieved response average robot in stabilizing the body is 8 seconds, Static Testing robot to stabilizing the body against the angel of roll in running the largest robot oscillations obtained 10 degrees, dynamic Testing robot to stabilizing the body against the angle of roll in run retrieved response average robot in stabilizing the body is 490 ms.
Publisher: OSA
Date: 2019
Publisher: AIP Publishing
Date: 09-2017
DOI: 10.1063/1.4996112
Abstract: The periodic-metamaterial-based perfect absorber has been studied broadly. Conversely, if the unit cell in the metamaterial-based absorber is arranged aperiodically (aperiodic-metamaterial-based absorber), how does it perform? Inspired by this, here we present a systematic study of the aperiodic-metamaterial-based absorber. By investigating the response of metamaterial absorbers based on periodic, Fibonacci, Thue-Morse, and quasicrystal lattices, we found that aperiodic-metamaterial-based absorbers could display similar absorption behaviors as the periodic one in one hand. However, their absorption behaviors show different tendency depending on the thicknesses of the spacer. Further studies on the angle and polarization dependence of the absorption behavior are also presented.
Publisher: The Optical Society
Date: 02-10-2017
DOI: 10.1364/OE.25.024872
Publisher: Wiley
Date: 07-11-2020
Publisher: Springer Science and Business Media LLC
Date: 23-12-2016
DOI: 10.1038/S41598-016-0027-Y
Abstract: Excitation and manipulation of surface plasmons (SPs) are essential in developing cutting-edge plasmonic devices for medical diagnostics, biochemical spectroscopy and communications. The most common approach involves designing an array of periodic slits or grating apertures that enables coupling of the incident light to the SP modes. In recent years, plasmonic resonances, including extraordinary optical transmission through periodic arrays, quasicrystals and random aperture arrays, have been investigated in the free space. However, most of the studies have been limited to the far field detection of the transmission resonance. Here, we perform near-field measurements of the SPs on quasicrystal metasurfaces. We discover that the reciprocal vector determines the propagation modes of the SPs in the quasicrystal lattice which can be well explained by the quasi-momentum conservation rule. Our findings demonstrate vast potential in developing plasmonic metasurfaces with unique device functionalities that are controlled by the propagation modes of the SPs in quasicrystals.
Publisher: Optica Publishing Group
Date: 03-2022
DOI: 10.1364/PRJ.440741
Abstract: Metasurface-empowered bound state in the continuum (BIC) provides a unique route for fascinating functional devices with infinitely high quality factors. This method is particularly attractive to the terahertz community because it may essentially solve the deficiencies in terahertz filters, sensors, lasers, and nonlinear sources. However, most BIC metasurfaces are limited to specified incident angles that seriously dim their application prospects. Here, we propose that a dual-period dielectric metagrating can support multiple families of BICs that originate from guided mode resonances in the dielectric grating and exhibit infinite quality factors at arbitrarily tilted incidence. This robustness was analyzed based on the Bloch theory and verified at tilted incident angles. We also demonstrate that inducing geometric asymmetry is an efficient way to manipulate the leakage and coupling of these BICs, which can mimic the electromagnetically induced transparency (EIT) effect in our dual-period metagrating. In this demonstration, a slow-light effect with a measured group delay of 117 ps was achieved. The incidence-insensitive BICs proposed here may greatly extend the application scenarios of the BIC effect. The high Q factor and outstanding slow-light effect in the metagrating show exciting prospects in realizing high-performance filters, sensors, and modulators for prompting terahertz applications.
Publisher: Optica Publishing Group
Date: 15-08-2022
DOI: 10.1364/PRJ.462119
Abstract: Recent moiré configurations provide a new platform for tunable and sensitive photonic responses, as their enhanced light–matter interactions originate from the relative displacement or rotation angle in a stacking bilayer or multilayer periodic array. However, previous findings are mostly focused on atomically thin condensed matter, with limitations on the fabrication of multilayer structures and the control of rotation angles. Structured microwave moiré configurations are still difficult to realize. Here, we design a novel moiré structure, which presents unprecedented capability in the manipulation of light–matter interactions. Based on the effective medium theory and S -parameter retrieval process, the rotation matrix is introduced into the dispersion relation to analyze the underlying physical mechanism, where the permittivity tensor transforms from a diagonal matrix to a fully populated one, whereas the permeability tensor evolves from a unit matrix to a diagonal one and finally becomes fully filled, so that the electromagnetic responses change drastically as a result of stacking and rotation. Besides, the experiment and simulation results reveal hybridization of eigenmodes, drastic manipulation of surface states, and magic angle properties by controlling the mutual rotation angles between two isolated layers. Here, not only a more precisely controllable bilayer hyperbolic metasurface is introduced to moiré physics, the findings also open up a new avenue to realize flat bands at arbitrary frequencies, which shows great potential in active engineering of surface waves and designing multifunctional plasmonic devices.
Publisher: American Chemical Society (ACS)
Date: 15-06-2017
Abstract: Coding metasurfaces allow us to study metamaterials from a fully digital perspective, enabling many exotic functionalities, such as anomalous reflections, broadband diffusions, and polarization conversion. Here, we propose a tensor coding metasurface at terahertz (THz) frequency that could take full-state controls of an electromagnetic wave in terms of its polarization state, phase and litude distributions, and wave-vector mode. Owing to the off-diagonal elements that dominant in the reflection matrix, each coding particle could reflect the normally incident wave to its cross-polarization with controllable phases, resulting in different coding digits. A 3-bit tensor coding metasurface with three coding sequences is taken as an ex le to show its full-state controls in reflecting a normally incident THz beam to anomalous directions with cross-polarizations and making a spatially propagating wave (PW) to surface wave (SW) conversion at the THz frequency. We show that the proposed PW-SW convertor based on the tensor coding metasurface supports both x- and y-polarized normal incidences, producing cross-polarized transverse-magnetic and transverse-electric modes of THz SWs, respectively.
Publisher: The Optical Society
Date: 22-09-2017
DOI: 10.1364/OE.25.024173
Publisher: Wiley
Date: 04-09-2016
Publisher: The Optical Society
Date: 25-01-2019
DOI: 10.1364/OE.27.002317
Publisher: Wiley
Date: 20-04-2017
Publisher: Springer Science and Business Media LLC
Date: 27-06-2018
DOI: 10.1038/S41377-018-0019-8
Abstract: By allowing almost arbitrary distributions of litude and phase of electromagnetic waves to be generated by a layer of sub-wavelength-size unit cells, metasurfaces have given rise to the field of meta-holography. However, holography with circularly polarized waves remains complicated as the achiral building blocks of existing meta-holograms inevitably contribute to holographic images generated by both left-handed and right-handed waves. Here we demonstrate how planar chirality enables the fully independent realization of high-efficiency meta-holograms for one circular polarization or the other. Such circular-polarization-selective meta-holograms are based on chiral building blocks that reflect either left-handed or right-handed circularly polarized waves with an orientation-dependent phase. Using terahertz waves, we experimentally demonstrate that this allows the straightforward design of reflective phase meta-holograms, where the use of alternating structures of opposite handedness yields independent holographic images for circularly polarized waves of opposite handedness with negligible polarization cross-talk.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2017
Publisher: The Optical Society
Date: 15-10-2014
DOI: 10.1364/OE.22.025931
Publisher: Optica Publishing Group
Date: 07-02-2023
DOI: 10.1364/OL.481967
Abstract: Near-perfect light harvesting of a metasurface-based absorber paves the way for achieving numerous potential applications in sensing, cloaking, and photovoltaics. Here, we present a reconfigurable perfect absorber based on a molybdenum ditelluride (MoTe 2 ) hybrid metasurface at terahertz (THz) frequency. By investigating the optical response of metasurface-based absorbers, a reconfigurable switching of dual-frequency perfect absorption to a new single-frequency absorption takes place when light illuminates MoTe 2 . Moreover, the absorption mechanism of the hybrid metasurface is well demonstrated with the analytical coupled-dipole model and impedance analysis. The proposed reconfigurable THz meta-absorber provides a new, to the best of our knowledge, route for active radar stealth, frequency-selective detection, and next-generation wireless communication.
Publisher: Optica Publishing Group
Date: 09-11-2020
DOI: 10.1364/OL.403377
Abstract: Chiral metamaterials have attracted wide interest because strong optical activity at designed frequencies could be achieved beyond that in natural materials. Here we propose an all-dielectric metamaterial with strong extrinsic circular dichroism and circular birefringence by periodically arranging symmetry-broken dielectric Mie resonators at terahertz frequencies. The strong interaction between the electric and magnetic resonances from circularly polarized incident waves dominates the performance of the all-dielectric metamaterial, which exhibits a 60% circular dichroism in transmission and a polarization rotation angle of 60° at maximum, respectively. Additionally, the spectral range of the circular dichroism with preserved litude can be adjusted continuously in the frequency range from 0.67–0.79 THz by tuning the tilt angle of the incident wave. Our findings will be of great potential in polarization control applications such as asymmetric transmission, optical isolation, and on-chip chiral manipulation.
Publisher: Wiley
Date: 13-08-2019
Publisher: American Physical Society (APS)
Date: 14-05-2018
Publisher: The Optical Society
Date: 26-06-2017
DOI: 10.1364/OE.25.015635
Publisher: The Optical Society
Date: 29-08-2017
Publisher: IOP Publishing
Date: 12-12-2019
Publisher: Wiley
Date: 12-03-2018
Publisher: Wiley
Date: 23-10-2019
Publisher: IOP Publishing
Date: 09-04-2018
Publisher: The Optical Society
Date: 28-04-2026
DOI: 10.1364/PRJ.6.001056
Publisher: SPIE-Intl Soc Optical Eng
Date: 05-07-2022
Publisher: SPIE
Date: 12-01-2018
DOI: 10.1117/12.2295507
No related grants have been discovered for Quanlong Yang.