SrIrO_(3),a Dirac material with a strong spin-orbit coupling(SOC),is a platform for studying topological properties in strongly correlated systems,where its band structure can be modulated by multiple factors,such as ...SrIrO_(3),a Dirac material with a strong spin-orbit coupling(SOC),is a platform for studying topological properties in strongly correlated systems,where its band structure can be modulated by multiple factors,such as crystal symmetry,elements doping,oxygen vacancies,magnetic field,and temperature.Here,we find that the engineered carrier density plays a critical role on the magnetoelectric transport properties of the topological semimetal SrIrO_(3).The decrease of carrier density subdues the weak localization and the associated negative magnetoresistance,while enhancing the SOC-induced weak anti-localization.Notably,the sample with the lowest carrier density exhibits high-field positive magnetoresistance,suggesting the presence of a Dirac cone.In addition,the anisotropic magnetoresistance indicates the anisotropy of the electronic structure near the Fermi level.The engineering of carrier density provides a general strategy to control the Fermi surface and electronic structure in topological materials.展开更多
We demonstrate the generation,spectral broadening and post-compression of second harmonic pulses using a thin beta barium borate(BBO)crystal on a fused-silica substrate as the nonlinear interaction medium.By combining...We demonstrate the generation,spectral broadening and post-compression of second harmonic pulses using a thin beta barium borate(BBO)crystal on a fused-silica substrate as the nonlinear interaction medium.By combining second harmonic generation in the BBO crystal with self-phase modulation in the fused-silica substrate,we efficiently generate millijoule-level broadband violet pulses from a single optical component.The second harmonic spectrum covers a range from long wave ultraviolet(down to 310 nm)to visible(up to 550 nm)with a bandwidth of 65 nm.Subsequently,we compress the second harmonic beam to a duration of 4.8 fs with a pulse energy of 0.64 mJ(5 fs with a pulse energy of 1.05 mJ)using chirped mirrors.The all-solid free-space apparatus is compact,robust and pulse energy scalable,making it highly advantageous for generating intense second harmonic pulses from near-infrared femtosecond lasers in the sub-5 fs regime.展开更多
We present a novel approach for Stimulated Raman Scattering(SRS)spectroscopy in which a hyper spectral resolution and high-speed spectral acquisition are achieved by employing amplified offset-phase controlled fs-puls...We present a novel approach for Stimulated Raman Scattering(SRS)spectroscopy in which a hyper spectral resolution and high-speed spectral acquisition are achieved by employing amplified offset-phase controlled fs-pulse bursts.We investigate the method by solving the coupled non-linear Schrödinger equations and validate it by numerically characterizing SRS in molecular nitrogen as a model compound.The spectral resolution of the method is found to be determined by the inverse product of the number of pulses in the burst and the intraburst pulse separation.The SRS spectrum is obtained through a motion-free scanning of the offset phase that results in a sweep of the Raman-shift frequency.Due to high spectral resolution and fast motion-free scanning the technique is beneficial for a number SRS-based applications such as gas sensing and chemical analysis.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.T2350005 and 5227123)the National Science Fund for Distinguished Young Scholars(Grant No.52225205)+1 种基金the National Key Research and Development Program of China(Grant Nos.2021YFA0718700 and 2023YFA1406500)the Fundamental Research Funds for the Central Universities。
文摘SrIrO_(3),a Dirac material with a strong spin-orbit coupling(SOC),is a platform for studying topological properties in strongly correlated systems,where its band structure can be modulated by multiple factors,such as crystal symmetry,elements doping,oxygen vacancies,magnetic field,and temperature.Here,we find that the engineered carrier density plays a critical role on the magnetoelectric transport properties of the topological semimetal SrIrO_(3).The decrease of carrier density subdues the weak localization and the associated negative magnetoresistance,while enhancing the SOC-induced weak anti-localization.Notably,the sample with the lowest carrier density exhibits high-field positive magnetoresistance,suggesting the presence of a Dirac cone.In addition,the anisotropic magnetoresistance indicates the anisotropy of the electronic structure near the Fermi level.The engineering of carrier density provides a general strategy to control the Fermi surface and electronic structure in topological materials.
文摘We demonstrate the generation,spectral broadening and post-compression of second harmonic pulses using a thin beta barium borate(BBO)crystal on a fused-silica substrate as the nonlinear interaction medium.By combining second harmonic generation in the BBO crystal with self-phase modulation in the fused-silica substrate,we efficiently generate millijoule-level broadband violet pulses from a single optical component.The second harmonic spectrum covers a range from long wave ultraviolet(down to 310 nm)to visible(up to 550 nm)with a bandwidth of 65 nm.Subsequently,we compress the second harmonic beam to a duration of 4.8 fs with a pulse energy of 0.64 mJ(5 fs with a pulse energy of 1.05 mJ)using chirped mirrors.The all-solid free-space apparatus is compact,robust and pulse energy scalable,making it highly advantageous for generating intense second harmonic pulses from near-infrared femtosecond lasers in the sub-5 fs regime.
基金supported by Austrian Science Fund(FWF)under ZK 9100-N,I 4566 and I 5592Prof.Zheltikov acknowledges the support from the Welch Foundation(Grant A-1801-20210327).
文摘We present a novel approach for Stimulated Raman Scattering(SRS)spectroscopy in which a hyper spectral resolution and high-speed spectral acquisition are achieved by employing amplified offset-phase controlled fs-pulse bursts.We investigate the method by solving the coupled non-linear Schrödinger equations and validate it by numerically characterizing SRS in molecular nitrogen as a model compound.The spectral resolution of the method is found to be determined by the inverse product of the number of pulses in the burst and the intraburst pulse separation.The SRS spectrum is obtained through a motion-free scanning of the offset phase that results in a sweep of the Raman-shift frequency.Due to high spectral resolution and fast motion-free scanning the technique is beneficial for a number SRS-based applications such as gas sensing and chemical analysis.
