The spatially-resolved laser-based high-resolution angle resolved photoemission spectroscopy(ARPES) measurements have been performed on the optimally-doped YBa_(2)Cu_(3)O_(7)-σ(Y123) superconductor. For the first tim...The spatially-resolved laser-based high-resolution angle resolved photoemission spectroscopy(ARPES) measurements have been performed on the optimally-doped YBa_(2)Cu_(3)O_(7)-σ(Y123) superconductor. For the first time, we found the region from the cleaved surface that reveals clear bulk electronic properties. The intrinsic Fermi surface and band structures of Y123 were observed. The Fermi surface-dependent and momentum-dependent superconducting gap was determined which is nodeless and consistent with the d+is gap form.展开更多
We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm,generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser.A β-BaB2O4 walk-off c...We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm,generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser.A β-BaB2O4 walk-off compensation configuration and a KBe2BO3F2 prism-coupled device are adopted for the generation of second harmonic and fourth harmonics,respectively.The highest power is 3.72 mW at 193 nm,and the fluctuation at 2.85 mW in 130 min is less than ±2%.展开更多
Ways on energy enhancement for single frequency oscillator are reported in this paper.By quantitative analysis on gain and loss coefficients for each cavity mode with inserted etalons,a 37 mJ,100 Hz high energy single...Ways on energy enhancement for single frequency oscillator are reported in this paper.By quantitative analysis on gain and loss coefficients for each cavity mode with inserted etalons,a 37 mJ,100 Hz high energy single-frequency Nd:YAG oscillator is obtained.The pulse energy is promoted by enhancement of nearly 7 times for a single frequency oscillator reported.The result proves that this method does help for energy enhancement.It has attractive potential for high energy single frequency oscillator design,especially on condition of intensive side pumped or long cavity laser,where strong competitors exist and are hard to be suppressed.展开更多
By partially doping Pb to effectively suppress the superstructure in single-layered cuprate Bi_2Sr_2CuO_(6+δ)(Pb-Bi2201) and annealing them in vacuum or in high pressure oxygen atmosphere, a series of high quality Pb...By partially doping Pb to effectively suppress the superstructure in single-layered cuprate Bi_2Sr_2CuO_(6+δ)(Pb-Bi2201) and annealing them in vacuum or in high pressure oxygen atmosphere, a series of high quality Pb-Bi2201 single crystals are obtained with T_c covering from 17 K to non-superconducting in the overdoped region. High resolution angle resolved photoemission spectroscopy measurements are carried out on these samples to investigate the evolution of the Fermi surface topology with doping in the normal state. Clear and complete Fermi surfaces are observed and quantitatively analyzed in all of these overdoped Pb-Bi2201 samples. A Lifshitz transition from holelike Fermi surface to electron-like Fermi surface with increasing doping is observed at a doping level of ~0.35. This transition coincides with the change that the sample undergoes superconducting-to-non-superconducting states.Our results reveal the emergence of an electron-like Fermi surface and the existence of a Lifshitz transition in heavily overdoped Bi2201 samples. This provides important information in understanding the connection between the disappearance of superconductivity and the Lifshitz transition in the overdoped region.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11888101 and 11974404)the National Key Research and Development Program of China (Grant Nos. 2021YFA1401800 and 2018YFA0704200)+3 种基金the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant Nos. XDB25000000 and XDB33000000)the Youth Innovation Promotion Association of CAS (Grant No. Y2021006)Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0301800)the Synergetic Extreme Condition User Facility (SECUF)。
文摘The spatially-resolved laser-based high-resolution angle resolved photoemission spectroscopy(ARPES) measurements have been performed on the optimally-doped YBa_(2)Cu_(3)O_(7)-σ(Y123) superconductor. For the first time, we found the region from the cleaved surface that reveals clear bulk electronic properties. The intrinsic Fermi surface and band structures of Y123 were observed. The Fermi surface-dependent and momentum-dependent superconducting gap was determined which is nodeless and consistent with the d+is gap form.
基金supported by the State Key Program for Basic Research of China (Grant No. 2010CB630706)National High Technology Research and Development Program of Chinathe National Natural Science Foundation of China (Grant No. 61138004)
文摘We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm,generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser.A β-BaB2O4 walk-off compensation configuration and a KBe2BO3F2 prism-coupled device are adopted for the generation of second harmonic and fourth harmonics,respectively.The highest power is 3.72 mW at 193 nm,and the fluctuation at 2.85 mW in 130 min is less than ±2%.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11504389)the Funds of Key Lab of Function Crystal and Laser Technology,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences
文摘Ways on energy enhancement for single frequency oscillator are reported in this paper.By quantitative analysis on gain and loss coefficients for each cavity mode with inserted etalons,a 37 mJ,100 Hz high energy single-frequency Nd:YAG oscillator is obtained.The pulse energy is promoted by enhancement of nearly 7 times for a single frequency oscillator reported.The result proves that this method does help for energy enhancement.It has attractive potential for high energy single frequency oscillator design,especially on condition of intensive side pumped or long cavity laser,where strong competitors exist and are hard to be suppressed.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0300300 and 2017YFA0302900the Strategic Priority Research Program(B)of Chinese Academy of Sciences under Grant Nos XDB07020300and XDB25000000+2 种基金the National Basic Research Program of China under Grant No 2015CB921300the National Natural Science Foundation of China under Grant Nos 11334010 and 11534007the Youth Innovation Promotion Association of Chinese Academy of Sciences under Grant No 2017013
文摘By partially doping Pb to effectively suppress the superstructure in single-layered cuprate Bi_2Sr_2CuO_(6+δ)(Pb-Bi2201) and annealing them in vacuum or in high pressure oxygen atmosphere, a series of high quality Pb-Bi2201 single crystals are obtained with T_c covering from 17 K to non-superconducting in the overdoped region. High resolution angle resolved photoemission spectroscopy measurements are carried out on these samples to investigate the evolution of the Fermi surface topology with doping in the normal state. Clear and complete Fermi surfaces are observed and quantitatively analyzed in all of these overdoped Pb-Bi2201 samples. A Lifshitz transition from holelike Fermi surface to electron-like Fermi surface with increasing doping is observed at a doping level of ~0.35. This transition coincides with the change that the sample undergoes superconducting-to-non-superconducting states.Our results reveal the emergence of an electron-like Fermi surface and the existence of a Lifshitz transition in heavily overdoped Bi2201 samples. This provides important information in understanding the connection between the disappearance of superconductivity and the Lifshitz transition in the overdoped region.
