Since the first isolated attosecond pulse was demonstrated through high-order harmonics generation(HHG)in 2001,researchers’interest in the ultrashort time region has expanded.However,one realizes a limitation for rel...Since the first isolated attosecond pulse was demonstrated through high-order harmonics generation(HHG)in 2001,researchers’interest in the ultrashort time region has expanded.However,one realizes a limitation for related research such as attosecond spectroscopy.The bottleneck is concluded to be the lack of a high-peak-power isolated attosecond pulse source.Therefore,currently,generating an intense attosecond pulse would be one of the highest priority goals.In this paper,we review our recent work of a TW-class parallel three-channel waveform synthesizer for generating a gigawatt-scale soft-X-ray isolated attosecond pulse(IAP)using HHG.By employing several stabilization methods,we have achieved a stable 50 mJ three-channel opticalwaveform synthesizer with a peak power at the multi-TW level.This optical-waveform synthesizer is capable of creating a stable intense optical field for generating an intense continuum harmonic beam thanks to the successful stabilization of all the parameters.Furthermore,the precision control of shot-to-shot reproducible synthesized waveforms is achieved.Through the HHG process employing a loose-focusing geometry,an intense shot-to-shot stable supercontinuum(50–70 eV)is generated in an argon gas cell.This continuum spectrum supports an IAP with a transform-limited duration of 170 as and a submicrojoule pulse energy,which allows the generation of a GW-scale IAP.Another supercontinuum in the soft-X-ray region with higher photon energy of approximately 100–130 eV is also generated in neon gas from the synthesizer.The transform-limited pulse duration is 106 as.Thus,the enhancement of HHG output through optimized waveform synthesis is experimentally proved.展开更多
基金supported,in part,by the Ministry of Education,Culture,Sports,Science and Technology of Japan(MEXT)through grants-in-aid under grants 17H01067,19H05628,and 21H01850in part by the FY 2019 Presidents Discretionary Funds of RIKEN+5 种基金in part by the Matsuo Foundation.B.X.acknowledges financial support from RIKEN for a Special Postdoctoral Researcher.Y.F.acknowledges support by the National Natural Science Foundation of China(92050107 and 61690222)Major Science and Technology Infrastructure Preresearch Program of the CAS(J20-021-III)Key Deployment Research Program of XIOPM(S19-020-III).K.M.acknowledges support by the MEXT Quantum Leap Flagship Program(MEXT Q-LEAP)grant number JP-MXS0118068681.P.L.acknowledges support by the National Key Research and Development Program(2017YFE0116600)the National Natural Science Foundation of China(91950202)the Science and Technology Planning Project of Guangdong Province(2018B090944001)O.D.M.acknowledges support by the priority program QUTIF(SPP1840 SOLSTICE)of Deutsche Forschungsgemeinschaft.
文摘Since the first isolated attosecond pulse was demonstrated through high-order harmonics generation(HHG)in 2001,researchers’interest in the ultrashort time region has expanded.However,one realizes a limitation for related research such as attosecond spectroscopy.The bottleneck is concluded to be the lack of a high-peak-power isolated attosecond pulse source.Therefore,currently,generating an intense attosecond pulse would be one of the highest priority goals.In this paper,we review our recent work of a TW-class parallel three-channel waveform synthesizer for generating a gigawatt-scale soft-X-ray isolated attosecond pulse(IAP)using HHG.By employing several stabilization methods,we have achieved a stable 50 mJ three-channel opticalwaveform synthesizer with a peak power at the multi-TW level.This optical-waveform synthesizer is capable of creating a stable intense optical field for generating an intense continuum harmonic beam thanks to the successful stabilization of all the parameters.Furthermore,the precision control of shot-to-shot reproducible synthesized waveforms is achieved.Through the HHG process employing a loose-focusing geometry,an intense shot-to-shot stable supercontinuum(50–70 eV)is generated in an argon gas cell.This continuum spectrum supports an IAP with a transform-limited duration of 170 as and a submicrojoule pulse energy,which allows the generation of a GW-scale IAP.Another supercontinuum in the soft-X-ray region with higher photon energy of approximately 100–130 eV is also generated in neon gas from the synthesizer.The transform-limited pulse duration is 106 as.Thus,the enhancement of HHG output through optimized waveform synthesis is experimentally proved.
