This contribution reports on application of low-wavenumber Raman scattering on acoustical vibrational modes of nanoparticles.Theoretical background as well as the experimental results in determination of oxide and sem...This contribution reports on application of low-wavenumber Raman scattering on acoustical vibrational modes of nanoparticles.Theoretical background as well as the experimental results in determination of oxide and semiconductor particle size distribution will be presented.展开更多
We report the realization of a synthetic magnetic field for photons and polaritons in a honeycomb lattice of coupled semiconductor micropillars.A strong synthetic field is induced in both the s and p orbital bands by ...We report the realization of a synthetic magnetic field for photons and polaritons in a honeycomb lattice of coupled semiconductor micropillars.A strong synthetic field is induced in both the s and p orbital bands by engineering a uniaxial hopping gradient in the lattice,giving rise to the formation of Landau levels at the Dirac points.We provide direct evidence of the sublattice symmetry breaking of the lowest-order Landau level wavefunction,a distinctive feature of synthetic magnetic fields.Our realization implements helical edge states in the gap between n=0 and n=±1 Landau levels,experimentally demonstrating a novel way of engineering propagating edge states in photonic lattices.In light of recent advances in the enhancement of polariton–polariton nonlinearities,the Landau levels reported here are promising for the study of the interplay between pseudomagnetism and interactions in a photonic system.展开更多
CSES(China Seismo-Electromagnetic Satellite) is a mission developed by CNSA(Chinese National Space Administration) and ASI(Italian Space Agency), to investigate the near-Earth electromagnetic, plasma and particle envi...CSES(China Seismo-Electromagnetic Satellite) is a mission developed by CNSA(Chinese National Space Administration) and ASI(Italian Space Agency), to investigate the near-Earth electromagnetic, plasma and particle environment, for studying the seismo-associated disturbances in the ionosphere-magnetosphere transition zone. The anthropogenic and electromagnetic noise,as well as the natural non-seismic electromagnetic emissions is mainly due to tropospheric activity. In particular, the mission aims to confirming the existence of possible temporal correlations between the occurrence of earthquakes for medium and strong magnitude and the observation in space of electromagnetic perturbations, plasma variations and precipitation of bursts with highenergy charged particles from the inner Van Allen belt. In this framework, the high energy particle detector(HEPD) of the CSES mission has been developed by the Italian LIMADOU Collaboration. HEPD is an advanced detector based on a tower of scintillators and a silicon tracker that provides good energy and angular resolution and a wide angular acceptance, for electrons of 3–100 Me V, protons of 30–200 Me V and light nuclei up to the oxygen. CSES satellite has been launched on February 2^(nd), 2018 from the Jiuquan Satellite Launch Center(China).展开更多
Non-Hermitian physics has found a fertile ground in optics. Recently, the study of mode coalescence, i.e., exceptional points, has led to the discovery of intriguing and counterintuitive phenomena. Degeneracies are ty...Non-Hermitian physics has found a fertile ground in optics. Recently, the study of mode coalescence, i.e., exceptional points, has led to the discovery of intriguing and counterintuitive phenomena. Degeneracies are typically modeled through the coupled mode theory to determine the behavior of eigenstates and eigenvalues. However,the complex nature of the eigenvalues makes their characterization from the response spectrum difficult. Here,we demonstrate that a coherent interferometric excitation allows estimation of both the real and imaginary parts of the eigenvalues. We study the clockwise and counter-clockwise modes in optical microresonators both in the case of Hermitian and non-Hermitian intermodal coupling. We show the conditions by which a resonant doublet,due to the dissipative coupling of counter-propagating modes caused by surface roughness backscattering, merges to a single Lorentzian. This permits us to estimate the optimal quality factor of the microresonator in the absence of modal coupling caused by backscattering. Furthermore, we demonstrate that a taiji microresonator working at an exceptional point shows a degeneracy splitting only in one propagation direction and not in the other. This follows from the strongly non-Hermitian intermodal coupling caused by the inner S-shaped waveguide.展开更多
文摘This contribution reports on application of low-wavenumber Raman scattering on acoustical vibrational modes of nanoparticles.Theoretical background as well as the experimental results in determination of oxide and semiconductor particle size distribution will be presented.
基金supported by the ERC grant Honeypol,the H2020-FETFLAG project PhoQus(820392)the QUANTERA project Interpol(ANR-QUAN-0003-05)+11 种基金the French National Research Agency project Quantum Fluids of Light(ANR-16-CE30-0021)the French government through the Programme Investissement d’Avenir(I-SITE ULNE/ANR-16-IDEX-0004 ULNE)managed by the Agence Nationale de la Recherchethe French RENATECH network,the Labex CEMPI(ANR-11-LABX-0007)the CPER Photonics for Society P4S and the Metropole Europeenne de Lille(MEL)via the project TFlightfinancial support from the FPI Scholarship No.BES-2015-074708the Spanish MINECO grant No.MAT2017-83722-Rsupported by funding from the ERC Starting Grant TopoColdsupported by JSPS KAKENHI Grant Number JP18H05857JST PRESTO Grant Number JPMJPR19L2JST CREST Grant Number JPMJCR19T1the RIKEN Incentive Research Projectthe Interdisciplinary Theoretical and Mathematical Sciences Program(iTHEMS)at RIKEN.
文摘We report the realization of a synthetic magnetic field for photons and polaritons in a honeycomb lattice of coupled semiconductor micropillars.A strong synthetic field is induced in both the s and p orbital bands by engineering a uniaxial hopping gradient in the lattice,giving rise to the formation of Landau levels at the Dirac points.We provide direct evidence of the sublattice symmetry breaking of the lowest-order Landau level wavefunction,a distinctive feature of synthetic magnetic fields.Our realization implements helical edge states in the gap between n=0 and n=±1 Landau levels,experimentally demonstrating a novel way of engineering propagating edge states in photonic lattices.In light of recent advances in the enhancement of polariton–polariton nonlinearities,the Landau levels reported here are promising for the study of the interplay between pseudomagnetism and interactions in a photonic system.
基金supported by the Italian Space Agency in the framework of the“Accordo Attuativo n.2016-16-H0 Progetto Limadou Fase E/Scienza”(CUP F12F1600011005)
文摘CSES(China Seismo-Electromagnetic Satellite) is a mission developed by CNSA(Chinese National Space Administration) and ASI(Italian Space Agency), to investigate the near-Earth electromagnetic, plasma and particle environment, for studying the seismo-associated disturbances in the ionosphere-magnetosphere transition zone. The anthropogenic and electromagnetic noise,as well as the natural non-seismic electromagnetic emissions is mainly due to tropospheric activity. In particular, the mission aims to confirming the existence of possible temporal correlations between the occurrence of earthquakes for medium and strong magnitude and the observation in space of electromagnetic perturbations, plasma variations and precipitation of bursts with highenergy charged particles from the inner Van Allen belt. In this framework, the high energy particle detector(HEPD) of the CSES mission has been developed by the Italian LIMADOU Collaboration. HEPD is an advanced detector based on a tower of scintillators and a silicon tracker that provides good energy and angular resolution and a wide angular acceptance, for electrons of 3–100 Me V, protons of 30–200 Me V and light nuclei up to the oxygen. CSES satellite has been launched on February 2^(nd), 2018 from the Jiuquan Satellite Launch Center(China).
基金Ministero dell'Istruzione,dell'Universita e della Ricerca[PRIN PELM(20177 PSCKT)].
文摘Non-Hermitian physics has found a fertile ground in optics. Recently, the study of mode coalescence, i.e., exceptional points, has led to the discovery of intriguing and counterintuitive phenomena. Degeneracies are typically modeled through the coupled mode theory to determine the behavior of eigenstates and eigenvalues. However,the complex nature of the eigenvalues makes their characterization from the response spectrum difficult. Here,we demonstrate that a coherent interferometric excitation allows estimation of both the real and imaginary parts of the eigenvalues. We study the clockwise and counter-clockwise modes in optical microresonators both in the case of Hermitian and non-Hermitian intermodal coupling. We show the conditions by which a resonant doublet,due to the dissipative coupling of counter-propagating modes caused by surface roughness backscattering, merges to a single Lorentzian. This permits us to estimate the optimal quality factor of the microresonator in the absence of modal coupling caused by backscattering. Furthermore, we demonstrate that a taiji microresonator working at an exceptional point shows a degeneracy splitting only in one propagation direction and not in the other. This follows from the strongly non-Hermitian intermodal coupling caused by the inner S-shaped waveguide.
