Ultrashort laser pulses can serve as fast probes to record instant events.The isolated attosecond pulses(IAPs)generated from high-order harmonic generation(HHG)have been shortened down to about 2 atomic units in time,...Ultrashort laser pulses can serve as fast probes to record instant events.The isolated attosecond pulses(IAPs)generated from high-order harmonic generation(HHG)have been shortened down to about 2 atomic units in time,empowering us to study quantum behaviors of electrons in atoms,molecules,and solids with unprecedented time resolution.Following the cutoff energy law of HHG,the shortest IAP reported so far is driven with short-wavelength infrared(SWIR)pulses,which require additional broadband frequency conversion techniques and raise the bar for attosecond researches.Here,we show that with fewcycle near-infrared(NIR)laser pulses,IAP with pulse duration of 51±4 as is generated during 1-fs linear polarization gate formed by generalized double optical gating(GDOG)technique.The characterization is done with attosecond streak camera,and phase reconstruction is performed with quick phase retrieval by omega oscillation filtering(qPROOF).Furthermore,we show that the IAP generation favors certain carrier envelope phases(CEPs)in the narrow gate,i.e.,IAP is only efficiently produced for certain CEPs,which eliminates the requirement of CEP stabilization.The demonstrated scheme for IAP generation in principle has much higher conversion efficiency than the long-wave driver scheme according to the wavelength scaling law of HHG.Our work suggests an alternative way to generate ultrashort IAPs by applying GDOG on few-cycle free-CEP NIR driving pulses,and is thereby of great importance to facilitate the development of attosecond science and technology.展开更多
基金supported by the National Key Research and Development Program of China(grant no.2019YFA0307703)the Major Research Plan of the National Natural Science Foundation of China(grant no.91850201)the National Natural Science Foundation of China(grant nos.12234020 and 11974426).
文摘Ultrashort laser pulses can serve as fast probes to record instant events.The isolated attosecond pulses(IAPs)generated from high-order harmonic generation(HHG)have been shortened down to about 2 atomic units in time,empowering us to study quantum behaviors of electrons in atoms,molecules,and solids with unprecedented time resolution.Following the cutoff energy law of HHG,the shortest IAP reported so far is driven with short-wavelength infrared(SWIR)pulses,which require additional broadband frequency conversion techniques and raise the bar for attosecond researches.Here,we show that with fewcycle near-infrared(NIR)laser pulses,IAP with pulse duration of 51±4 as is generated during 1-fs linear polarization gate formed by generalized double optical gating(GDOG)technique.The characterization is done with attosecond streak camera,and phase reconstruction is performed with quick phase retrieval by omega oscillation filtering(qPROOF).Furthermore,we show that the IAP generation favors certain carrier envelope phases(CEPs)in the narrow gate,i.e.,IAP is only efficiently produced for certain CEPs,which eliminates the requirement of CEP stabilization.The demonstrated scheme for IAP generation in principle has much higher conversion efficiency than the long-wave driver scheme according to the wavelength scaling law of HHG.Our work suggests an alternative way to generate ultrashort IAPs by applying GDOG on few-cycle free-CEP NIR driving pulses,and is thereby of great importance to facilitate the development of attosecond science and technology.
