Controlling terahertz(THz)polarization with high stability and tunability is essential for achieving further progress in ultrafast spectroscopy,structured-light manipulation,and quantum information processing.Here,we ...Controlling terahertz(THz)polarization with high stability and tunability is essential for achieving further progress in ultrafast spectroscopy,structured-light manipulation,and quantum information processing.Here,we propose a magnetized plasma platform for dynamic THz polarization control by exploiting the intrinsic birefringence between extraordinary and ordinary modes.We identify a strong-magnetization,zero-group-velocity-mismatch regime where the two modes share matched group velocities while retaining finite phase birefringence,enabling robust,phase-stable spin angular momentum control.By tuning the plasma length and magnetic field,we realize programmable phase retardation and demonstrate universal single-qubit gates through parameterized unitary operations.Full-wave particle-in-cell simulations validate high-fidelity polarization transformations across the Poincarésphere and demonstrate the potential for generating structured vector beams under spatially varying magnetic fields.The platform offers ultrafast response,resilience to extreme THz intensities,and in situ tunability,positioning magnetized plasmas as a versatile and damage-resilient medium for next-generation THz polarization control and structured-wave applications.展开更多
The variable polarity power source which incorporates a constant current power and a secondary inverter does not need special apparatus for stabilizing arc. The pulse for stabilizing arc is created by the circuit stru...The variable polarity power source which incorporates a constant current power and a secondary inverter does not need special apparatus for stabilizing arc. The pulse for stabilizing arc is created by the circuit structure itself. The paper analyzes the principle of acquiring the pulse, provides the better method to improve the arc stabilization under smaller welding current. Test shows the arc is highly stable , and the process has no high frequency electromagnetic interference, which is suitable for automatic welding case.展开更多
Miniaturization of Frequency Selective Surface's ( FSS's) size is significant for its application in the limited space. In this paper, a novel methodology for designing low-profile FSS is discussed, and a corr...Miniaturization of Frequency Selective Surface's ( FSS's) size is significant for its application in the limited space. In this paper, a novel methodology for designing low-profile FSS is discussed, and a corresponding multi-layer structure with lumped elements for band-pass response is presented. Based on the equivalent circuit theory,the inductive designed center layer is firstly discussed. Then different numbers of additional capacitive designed layers are added and their performances are presented. Finally,the lumped elements are added both between adjacent layers and between adjacent cells of the additional layers so that the miniaturization performance can be further improved. The simulations for each structure in waves of different polarizations and incident angles are conducted,and the results are presented,which demonstrate the claimed characteristics of the proposed structure.展开更多
Size-driven transition of an antiferroelectric into a polar ferroelectric or ferrielectric state is a strongly debated issue from both experimental and theoretical perspectives.While critical thickness limits for such...Size-driven transition of an antiferroelectric into a polar ferroelectric or ferrielectric state is a strongly debated issue from both experimental and theoretical perspectives.While critical thickness limits for such transitions have been explored,a bottom-up approach in the ultrathin limit considering few atomic layers could provide insight into the mechanism of stabilization of the polar phases over the antipolar phase seen in bulk PbZrO_(3).Here,we use first-principles density functional theory to predict the stability of polar phases in Pt/PbZrO_(3)/Pt nanocapacitors.In a few atomic layer thick slabs of PbZrO_(3) sandwiched between Pt electrodes,we find that the polar phase originating from the well established R3c phase of bulk PbZrO_(3) is energetically favorable over the antipolar phase originating from the Pbam phase of bulk PbZrO_(3).The famous triple-well potential of antiferroelectric PbZrO_(3) is modified in the nanocapacitor limit in such a way as to swap the positions of the global and local minima,stabilizing the polar phase relative to the antipolar one.The size effect is decomposed into the contributions from dimensionality reduction,surface charge screening,and interfacial relaxation,which reveals that it is the creation of well-compensated interfaces that stabilizes the polar phases over the antipolar ones in nanoscale PbZrO_(3).展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 12175058 and 11921006)the National Grand Instrument Project (No. 2019YFF01014402)the Beijing Distinguished Young Scientist Program and National Grand Instrument Project No. SQ2019YFF01014400
文摘Controlling terahertz(THz)polarization with high stability and tunability is essential for achieving further progress in ultrafast spectroscopy,structured-light manipulation,and quantum information processing.Here,we propose a magnetized plasma platform for dynamic THz polarization control by exploiting the intrinsic birefringence between extraordinary and ordinary modes.We identify a strong-magnetization,zero-group-velocity-mismatch regime where the two modes share matched group velocities while retaining finite phase birefringence,enabling robust,phase-stable spin angular momentum control.By tuning the plasma length and magnetic field,we realize programmable phase retardation and demonstrate universal single-qubit gates through parameterized unitary operations.Full-wave particle-in-cell simulations validate high-fidelity polarization transformations across the Poincarésphere and demonstrate the potential for generating structured vector beams under spatially varying magnetic fields.The platform offers ultrafast response,resilience to extreme THz intensities,and in situ tunability,positioning magnetized plasmas as a versatile and damage-resilient medium for next-generation THz polarization control and structured-wave applications.
基金This research was supported inpart by the Found ation !(No .990 951 1 1 2 )for Research admini stered by HarbinInstituteof Te
文摘The variable polarity power source which incorporates a constant current power and a secondary inverter does not need special apparatus for stabilizing arc. The pulse for stabilizing arc is created by the circuit structure itself. The paper analyzes the principle of acquiring the pulse, provides the better method to improve the arc stabilization under smaller welding current. Test shows the arc is highly stable , and the process has no high frequency electromagnetic interference, which is suitable for automatic welding case.
基金Sponsored by the National Natural Science Foundation of China(Grant No.60801015 and 61001036)the Special Funds Projects for Technological and Innovative Talent of Harbin City(Grant No.2010RFXXG010)+2 种基金the Fundamental Research Funds for the Central Universities(No.HIT.IBRSEM.2009 and HIT.NSRIF.201153)China Postdoctoral Science Foundation(Grant No.LBH-Z10126)Heilongjiang Province Postdoctoral Foundation(Grant No.20110491093)
文摘Miniaturization of Frequency Selective Surface's ( FSS's) size is significant for its application in the limited space. In this paper, a novel methodology for designing low-profile FSS is discussed, and a corresponding multi-layer structure with lumped elements for band-pass response is presented. Based on the equivalent circuit theory,the inductive designed center layer is firstly discussed. Then different numbers of additional capacitive designed layers are added and their performances are presented. Finally,the lumped elements are added both between adjacent layers and between adjacent cells of the additional layers so that the miniaturization performance can be further improved. The simulations for each structure in waves of different polarizations and incident angles are conducted,and the results are presented,which demonstrate the claimed characteristics of the proposed structure.
基金support by the U.S.National Science Foundation under grant No.DMR-2219476I.P.acknowledges financial support by the U.S.Department of Energy,Office of Basic Energy Sciences,Division of Materials Sciences and Engineering under grant DE-SC0005245+3 种基金Computational support was provided by the National Energy Research Scientific Computing Center(NERSC)a U.S.Department of Energy,Office of Science User Facility located at Lawrence Berkeley National Laboratory,operated under Contract No.DE-AC02-05CH11231 using NERSC award BES-ERCAP-0025236L.J.acknowledges support from SFI grant SFI/21/US/3785A.K.gratefully acknowledges support from Department of Education and Learning NI through grant USI-211.
文摘Size-driven transition of an antiferroelectric into a polar ferroelectric or ferrielectric state is a strongly debated issue from both experimental and theoretical perspectives.While critical thickness limits for such transitions have been explored,a bottom-up approach in the ultrathin limit considering few atomic layers could provide insight into the mechanism of stabilization of the polar phases over the antipolar phase seen in bulk PbZrO_(3).Here,we use first-principles density functional theory to predict the stability of polar phases in Pt/PbZrO_(3)/Pt nanocapacitors.In a few atomic layer thick slabs of PbZrO_(3) sandwiched between Pt electrodes,we find that the polar phase originating from the well established R3c phase of bulk PbZrO_(3) is energetically favorable over the antipolar phase originating from the Pbam phase of bulk PbZrO_(3).The famous triple-well potential of antiferroelectric PbZrO_(3) is modified in the nanocapacitor limit in such a way as to swap the positions of the global and local minima,stabilizing the polar phase relative to the antipolar one.The size effect is decomposed into the contributions from dimensionality reduction,surface charge screening,and interfacial relaxation,which reveals that it is the creation of well-compensated interfaces that stabilizes the polar phases over the antipolar ones in nanoscale PbZrO_(3).
