We report the experimental demonstration of fluorescence of CdSe quantum dots with surface plasmon excitation in deep-ultraviolet （deep-UV） region. Surface plasmon resonance in deep-UV is excited by aluminum thin fi...We report the experimental demonstration of fluorescence of CdSe quantum dots with surface plasmon excitation in deep-ultraviolet （deep-UV） region. Surface plasmon resonance in deep-UV is excited by aluminum thin film in the Kretschmann-Raether geometry. Considering the oxidation thickness of aluminum, the experimental results of incident angle dependence of reflectance show good agreement with Fresnel theory. Surface plasmon resonance with 19 nm-thick aluminum and 5 nm-thick almnina was excited at the incident angle of 48 degrees for 266 nm excitation. Fluorescence of CdSe quantum dots coated on this aluminum film was observed by the surface plasmon excitation.展开更多
Antiferromagnets exhibit distinctive characteristics such as ultrafast dynamics and robustness against perturbative fields,thereby attracting considerable interest in fundamental physics and technological applications...Antiferromagnets exhibit distinctive characteristics such as ultrafast dynamics and robustness against perturbative fields,thereby attracting considerable interest in fundamental physics and technological applications.Recently,it was revealed that the Néel vector can be switched by a current-induced staggered(Néel)spin-orbit torque in antiferromagnets with the parity-time symmetry,and furthermore,a nonsymmorphic symmetry enables the control of Dirac fermions.However,the real-time dynamics of the magnetic and electronic structures remain largely unexplored.Here,we propose a theory of the ultrafast dynamics in antiferromagnetic Dirac semimetals and show that the Néel vector is rotated in the picosecond timescale by the terahertz-pulse-induced Néel spin-orbit torque and other torques originating from magnetic anisotropies.This reorientation accompanies the modulation of the mass of Dirac fermions and can be observed in real time by the magneto-optical effects.Our results provide a theoretical basis for emerging ultrafast antiferromagnetic spintronics combined with the topological aspects of materials.展开更多
文摘We report the experimental demonstration of fluorescence of CdSe quantum dots with surface plasmon excitation in deep-ultraviolet （deep-UV） region. Surface plasmon resonance in deep-UV is excited by aluminum thin film in the Kretschmann-Raether geometry. Considering the oxidation thickness of aluminum, the experimental results of incident angle dependence of reflectance show good agreement with Fresnel theory. Surface plasmon resonance with 19 nm-thick aluminum and 5 nm-thick almnina was excited at the incident angle of 48 degrees for 266 nm excitation. Fluorescence of CdSe quantum dots coated on this aluminum film was observed by the surface plasmon excitation.
基金One of the authors,Sumio Ishihara,passed away on 7 November 2020 during the preparation of the manuscript.We thank H.Matsueda and Y.Masaki for their valuable comments and critical reading of the manuscript.This work was supported by JSPS KAKENHI Grant Nos.JP19K23419,JP20K14394,JP17H02916,JP18H05208,and JP20H00121The numerical calculations were performed using the facilities of the Supercomputer Center,the Institute for Solid State Physics,the University of Tokyo。
文摘Antiferromagnets exhibit distinctive characteristics such as ultrafast dynamics and robustness against perturbative fields,thereby attracting considerable interest in fundamental physics and technological applications.Recently,it was revealed that the Néel vector can be switched by a current-induced staggered(Néel)spin-orbit torque in antiferromagnets with the parity-time symmetry,and furthermore,a nonsymmorphic symmetry enables the control of Dirac fermions.However,the real-time dynamics of the magnetic and electronic structures remain largely unexplored.Here,we propose a theory of the ultrafast dynamics in antiferromagnetic Dirac semimetals and show that the Néel vector is rotated in the picosecond timescale by the terahertz-pulse-induced Néel spin-orbit torque and other torques originating from magnetic anisotropies.This reorientation accompanies the modulation of the mass of Dirac fermions and can be observed in real time by the magneto-optical effects.Our results provide a theoretical basis for emerging ultrafast antiferromagnetic spintronics combined with the topological aspects of materials.
