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Layer-controlled nonlinear terahertz valleytronics in two-dimensional semimetal and semiconductor PtSe_(2) 被引量:2
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作者 Minoosh Hemmat Sabrine Ayari +16 位作者 Martin Micica Hadrien Vergnet Shasha Guo Mehdi Arfaoui Xuechao Yu Daniel Vala Adrien Wright Kamil Postava Juliette mangeney Francesca Carosella Sihem Jaziri Qi Jie Wang Zheng Liu Jérôme Tignon Robson Ferreira Emmanuel Baudin Sukhdeep Dhillon 《InfoMat》 SCIE CSCD 2023年第11期49-63,共15页
Platinum diselenide(PtSe_(2))is a promising two-dimensional(2D)material for the terahertz(THz)range as,unlike other transition metal dichalcogenides(TMDs),its bandgap can be uniquely tuned from a semiconductor in the ... Platinum diselenide(PtSe_(2))is a promising two-dimensional(2D)material for the terahertz(THz)range as,unlike other transition metal dichalcogenides(TMDs),its bandgap can be uniquely tuned from a semiconductor in the nearinfrared to a semimetal with the number of atomic layers.This gives the material unique THz photonic properties that can be layer-engineered.Here,we demonstrate that a controlled THz nonlinearity—tuned from monolayer to bulk PtSe_(2)—can be realized in wafer size polycrystalline PtSe_(2)through the generation of ultrafast photocurrents and the engineering of the bandstructure valleys.This is combined with the PtSe_(2)layer interaction with the substrate for a broken material centrosymmetry,permitting a second order nonlinearity.Further,we show layer dependent circular dichroism,where the sign of the ultrafast currents and hence the phase of the emitted THz pulse can be controlled through the excitation of different bandstructure valleys.In particular,we show that a semimetal has a strong dichroism that is absent in the monolayer and few layer semiconducting limit.The microscopic origins of this TMD bandstructure engineering are highlighted through detailed DFT simulations,and shows the circular dichroism can be controlled when PtSe_(2)becomes a semimetal and when the K-valleys can be excited.As well as showing that PtSe_(2)is a promising material for THz generation through layer controlled optical nonlinearities,this work opens up a new class of circular dichroism materials beyond the monolayer limit that has been the case of traditional TMDs,and impacting a range of domains from THz valleytronics,THz spintronics to harmonic generation. 展开更多
关键词 2D transition metal dichalcogenides Dirac semimetal optical nonlinearities TERAHERTZ valleytronics
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Ultrafast response of harmonic modelocked THz lasers 被引量:5
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作者 Feihu Wang Valentino Pistore +8 位作者 Michael Riesch Hanond Nong Pierre-Baptiste Vigneron Raffaele Colombelli Olivier Parillaud Juliette mangeney Jerome Tignon Christian Jirauschek Sukhdeep S.Dhillon 《Light(Science & Applications)》 SCIE EI CAS CSCD 2020年第1期1530-1537,共8页
The use of fundamental modelocking to generate short terahertz(THz)pulses and THz frequency combs from semiconductor lasers has become a routine affair,using quantum cascade lasers(QCLs)as a gain medium.However,unlike... The use of fundamental modelocking to generate short terahertz(THz)pulses and THz frequency combs from semiconductor lasers has become a routine affair,using quantum cascade lasers(QCLs)as a gain medium.However,unlike classic laser diodes,no demonstrations of harmonic modelocking,active or passive,have been shown in THz QCLs,where multiple pulses per round trip are generated when the laser is modulated at the harmonics of the cavity’s fundamental round-trip frequency.Here,using time-resolved THz techniques,we show for the first time harmonic injection and mode-locking in which THz QCLs are modulated at the harmonics of the round-trip frequency.We demonstrate the generation of the harmonic electrical beatnote within a QCL,its injection locking to an active modulation and its direct translation to harmonic pulse generation using the unique ultrafast nature of our approach.Finally,we show indications of self-starting harmonic emission,i.e.,without external modulation,where the QCL operates exclusively on a harmonic(up to its 15th harmonic)of the round-trip frequency.This behaviour is supported by time-resolved simulations of induced gain and loss in the system and shows the importance of the electronic,as well as photonic,nature of QCLs.These results open up the prospect of passive harmonic modelocking and THz pulse generation,as well as the generation of low-noise microwave generation in the hundreds of GHz region. 展开更多
关键词 passive HARMONIC HARMONICS
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High Q and sub-wavelength THz electric field confinement in ultrastrongly coupled THz resonators
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作者 SIMON MESSELOT SOLEN COEYMANS +2 位作者 JEROME TIGNON SUKHDEEP DHILLON JULIETTE mangeney 《Photonics Research》 SCIE EI CAS CSCD 2023年第7期1203-1216,共14页
The control of light–matter coupling at the single electron level is currently a subject of growing interest for the development of novel quantum devices and for studies and applications of quantum electrodynamics.In... The control of light–matter coupling at the single electron level is currently a subject of growing interest for the development of novel quantum devices and for studies and applications of quantum electrodynamics.In the terahertz(THz)spectral range,this raises the particular and difficult challenge of building electromagnetic resonators that can conciliate low mode volume and high quality factor.Here,we report on hybrid THz cavities based on ultrastrong coupling between a Tamm cavity and an LC circuit metamaterial and show that they can combine high quality factors of up to Q=37 with a deep-subwavelength mode volume of V=3.2×10^(-4)λ^(3).Our theoretical and experimental analysis of the coupled mode properties reveals that,in general,the ultrastrong coupling between a metamaterial and a Fabry–Perot cavity is an effective tool to almost completely suppress radiative losses and,thus,ultimately limit the total losses to the losses in the metallic layer.These Tamm cavity-LC metamaterial coupled resonators open a route toward the development of single photon THz emitters and detectors and to the exploration of ultrastrong THz light–matter coupling with a high degree of coherence in the few to single electron limit. 展开更多
关键词 COUPLING CAVITY coupled
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太阳射电Ⅲ型爆发群的频谱分析
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作者 M.Pick A.mangeney 赵仁扬 《天文学报》 CSCD 北大核心 1991年第1期28-35,共8页
本文利用Nancay射电日象仪在5个频率上所获得的Ⅲ型爆发群的高时间分辨率和高灵敏度的总强度和圆偏振辐射及其源位置和大小的观测资料,采用Fourier变换频谱分析方法,对58个事件作了细致研究.研究进一步证实了在Ⅲ型爆发群中的确存在着... 本文利用Nancay射电日象仪在5个频率上所获得的Ⅲ型爆发群的高时间分辨率和高灵敏度的总强度和圆偏振辐射及其源位置和大小的观测资料,采用Fourier变换频谱分析方法,对58个事件作了细致研究.研究进一步证实了在Ⅲ型爆发群中的确存在着周期性,绝大多数事件的周期性处于1秒到6秒之间,而且大部分事件还呈现出其置信度水平高于90%的多重周期性.尤其重要的是,我们分析出Ⅲ型爆发群可分为两个性质不同的类型:一类具有弱偏振,并在长至6秒的宽范围中呈现出周期性,而且具有较大尺度的爆发源;另一类则具有强偏振,且呈现出不长于2秒的短周期性,具有较小尺度的致密源. 展开更多
关键词 太阳 射电 射电爆发 频谱分析
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盾牌δ型变星HD213534的多重频率
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作者 傅建宁 蒋世仰 +9 位作者 E.MICHEL J.A.BELMONTE M.ALVAREZ M.CHEVRETON M.AUVERGNE M.J.GOUPIL A.BAGLIN A.mangeney M.CHALOUPI T.ROCA CORTES 《天文学报》 CSCD 北大核心 1992年第3期327-336,共10页
本文利用三国联合观测获得的大量高精度光电测光数据,采用Fourier周期分析的方法,得到了δScuti型变星HD213534的多重脉动周期,认为该星存在五个以上的脉动频率.文中给出了该星的各项参量,并对其脉动模式进行了讨论,认为HD213534星是一... 本文利用三国联合观测获得的大量高精度光电测光数据,采用Fourier周期分析的方法,得到了δScuti型变星HD213534的多重脉动周期,认为该星存在五个以上的脉动频率.文中给出了该星的各项参量,并对其脉动模式进行了讨论,认为HD213534星是一颗以非径向脉动为主的多重周期脉动变星. 展开更多
关键词 周期分析 变星 δ型 测光 频率
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Cavity-based photoconductive sources for real-time terahertz imaging 被引量:1
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作者 J.HAWECKER V.PISTORE +8 位作者 A.MINASYAN K.MAUSSANG J.PALOMO I.SAGNES J.-M.MANCEAU R.COLOMBELLI J.TIGNON J.mangeney AND S.S.DHILLON 《Photonics Research》 SCIE EI CSCD 2020年第6期858-863,共6页
Optically driven photoconductive switches are one of the predominant sources currently used in terahertz im-aging systems.However,owing to their low average powers,only raster-based images can be taken,resulting in sl... Optically driven photoconductive switches are one of the predominant sources currently used in terahertz im-aging systems.However,owing to their low average powers,only raster-based images can be taken,resulting in slow acquisition.In this work,we show that by placing a photoconductive switch within a cavity,we are able to generate absolute average THz powers of 181μW with the frequency of the THz emission centered at 1.5 THz-specifications ideally adapted to applications such as non-destructive imaging.The cavity is based on a metal-insulator-metal structure that permits an en hancement of the average power by almost 1 order of magnitude compared to a standard structure,while conserving a broadband spectral response.We demonstrate proof-of-principle real-time imaging using this source,with the broadband spectrum permitting to eliminate strong diffraction artifacts. 展开更多
关键词 PHOTOCONDUCTIVE SOURCES CAVITY
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