Isolated attosecond extreme-ultraviolate(XUV)pulses are generated based on high-harmonic-generation from a neon gas cell driven by carrier-envelope phase stabilized sub-5-fs Ti:sapphire laser pulses at repetition rate...Isolated attosecond extreme-ultraviolate(XUV)pulses are generated based on high-harmonic-generation from a neon gas cell driven by carrier-envelope phase stabilized sub-5-fs Ti:sapphire laser pulses at repetition rate of 1kHz.Temporal characterization of isolated attosecond XUV pulses is demonstrated to be 160-attosecond by attosecond streaking spectroscopy.The development of attosecond source and streaking spectroscopy will allow scientists to explore the electron dynamics in matter.展开更多
We realize a wide spaced frequency comb by using an external low-fineness Fabry–Pérot(F-P)cavity to filter few-cycle laser pulses from a Kerr-lens mode-locked Ti:sapphire laser at the fundamental repetition rate...We realize a wide spaced frequency comb by using an external low-fineness Fabry–Pérot(F-P)cavity to filter few-cycle laser pulses from a Kerr-lens mode-locked Ti:sapphire laser at the fundamental repetition rate of 350 MHz.Mode spacing as wide as 15 GHz with spectrum covered from 690 nm to 710 nm is demonstrated,corresponding to a filter multiple of about 43.The scanning transmission peaks after the F-P cavity with cavity lengths are also simulated numerically,and the results are in agreement with the experiment.展开更多
We demonstrate an octave-spanning Kerr-lens mode-locked Ti:sapphire laser with double-chirped mirrors(DCMs),BaF_(2) wedges and plate,which generates laser pulses in the spectrum range from 600 nm to 1200 nm at-45 dB b...We demonstrate an octave-spanning Kerr-lens mode-locked Ti:sapphire laser with double-chirped mirrors(DCMs),BaF_(2) wedges and plate,which generates laser pulses in the spectrum range from 600 nm to 1200 nm at-45 dB below the maximum and the duration of 8.5 fs at the repetition rate of 80 MHz.The average output power is 100 mW under 5 W pump power.By carefully adjusting the insertion of BaF_(2) wedges and the optimization position of Ti:sapphire crystal in the cavity,we can obtain the smooth swings in the interferometric autocorrelation trace due to good third-order dispersion compensation.展开更多
We demonstrate an experimental setup of a tunable ultrafast laser source ty sum-frequency generation (SFG)between a mode-locking Ti:sapphire laser and a Nd:YVO4 laser.The generated wavelength by SFG is tunable from 45...We demonstrate an experimental setup of a tunable ultrafast laser source ty sum-frequency generation (SFG)between a mode-locking Ti:sapphire laser and a Nd:YVO4 laser.The generated wavelength by SFG is tunable from 450nm to 480nm with timing jitter no more than 1 ps.The average output power is over 20mW and the maximum is about 30mW at 457nm.This ultrafast laser is a simple and easy tuning source applied to some pump-probe spectroscopy and ultrafast dynamics experiments.展开更多
We demonstrate a 100-TW-class femtosecond Ti:sapphire laser running at a repetition rate of 0.1Hz based on a 20TW/10 Hz laser facility (XL-Ⅱ).Pumping the new stage amplifier with a 25J green Nd:glass laser,we success...We demonstrate a 100-TW-class femtosecond Ti:sapphire laser running at a repetition rate of 0.1Hz based on a 20TW/10 Hz laser facility (XL-Ⅱ).Pumping the new stage amplifier with a 25J green Nd:glass laser,we successfully improve the laser energy to 3.4J with duration of 29 fs,corresponding to a peak power of 11 7 TW.展开更多
We present the observation of the additional spectral components between the odd order harmonics in the harmonic spectrum generated from argon gas driven by sub-5-fs laser pulses.The theoretical analysis shows that th...We present the observation of the additional spectral components between the odd order harmonics in the harmonic spectrum generated from argon gas driven by sub-5-fs laser pulses.The theoretical analysis shows that the asymmetric laser field in both spatial and temporal domains leads to this complicated spectrum structure of high order harmonics.展开更多
A real-time ion spectrometer mainly based on a high-resolution Thomson parabola and a plastic scintillator is designed and developed.The spectrometer is calibrated by protons from an electrostatic accelerator.The feas...A real-time ion spectrometer mainly based on a high-resolution Thomson parabola and a plastic scintillator is designed and developed.The spectrometer is calibrated by protons from an electrostatic accelerator.The feasibility and reliability of the diagnostics are demonstrated in laser-driven ion acceleration experiments performed on the XL-II laser facility.The proton spectrum extrapolated from the scintillator data is in excellent agreement with the CR39 spectrum in terms of beam temperature and the cutoff energy.This real-time spectrometer allows an online measurement of the ion spectra in single shot,which enables efficient and statistical studies and applications in high-repetition-rate laser acceleration experiments.展开更多
The effects of laser polarization on super-hot electron (> 100 keV) generation have been studied in the interaction of femtosecond laser light (800 nm, 150 fs, 6 × 10^(15) W·cm^(-2)) with a pre-formed pla...The effects of laser polarization on super-hot electron (> 100 keV) generation have been studied in the interaction of femtosecond laser light (800 nm, 150 fs, 6 × 10^(15) W·cm^(-2)) with a pre-formed plasma from a slab Cu target. For p-polarized laser pulses, high-energy γ-rays of the energy ~400keV were detected. The electron temperatures deduced from the γ-ray spectra were 66 and 52keV, respectively, in normal and reflective directions of the solid target, and hot electrons were emitted out of the plasma mainly in the normal direction. In contrast, there were nearly no γ-rays >100keV found for s-polarized laser pulses. The hot electron temperature was 26keV and the emission of hot electrons was parallel to the laser field. The superposition of resonant field with electrostatic field excited by escaping electrons may contribute to the high-energy γ-ray or super-hot electron (> 100 keV) generation.展开更多
By observing the fundamental and second harmonic emission from a plasma produced by a 150fs,5mJ laser at 800nm,the electron temperature,the expansion speed and the scalelength of the plasma have been diagnosed.Moreove...By observing the fundamental and second harmonic emission from a plasma produced by a 150fs,5mJ laser at 800nm,the electron temperature,the expansion speed and the scalelength of the plasma have been diagnosed.Moreover the polarization of the fundamental and second harmonic emission has been studied.This could be a useful diagnostic for modulation at the critical surface of the plasma.展开更多
The γ-rays with energies up to 300keV have been observed from plasmas produced by femtosecond laser pulses at a focused intensity of 5 × 10^(15) W.cm^(-2).μm^(2) irradiating Ta,Mo,and Cu targets.By introducing ...The γ-rays with energies up to 300keV have been observed from plasmas produced by femtosecond laser pulses at a focused intensity of 5 × 10^(15) W.cm^(-2).μm^(2) irradiating Ta,Mo,and Cu targets.By introducing an 8% prepulse of 70ps before the main pulse,the fraction of high energy γ-ray photons(hv>l00keV)was significantly enhanced relative to low energy photons(hv<100 keV).展开更多
基金Supported by the National Basic Research Program of China(973 Program)under Grant No 2013CB922402the Instrument Developing Project of the Chinese Academy of Sciences under Grant No 2010004,and the National Natural Science Foundation of China under Grant No 11074298.
文摘Isolated attosecond extreme-ultraviolate(XUV)pulses are generated based on high-harmonic-generation from a neon gas cell driven by carrier-envelope phase stabilized sub-5-fs Ti:sapphire laser pulses at repetition rate of 1kHz.Temporal characterization of isolated attosecond XUV pulses is demonstrated to be 160-attosecond by attosecond streaking spectroscopy.The development of attosecond source and streaking spectroscopy will allow scientists to explore the electron dynamics in matter.
基金Supported by the National Natural Sciences Foundation of China under Grant Nos 11078022 and 60808007the National Basic Research Program of China under Grant No 2012CB821304the Knowledge Innovation Program of Chinese Academy of Sciences under Grant No KJCX-YW-W21.
文摘We realize a wide spaced frequency comb by using an external low-fineness Fabry–Pérot(F-P)cavity to filter few-cycle laser pulses from a Kerr-lens mode-locked Ti:sapphire laser at the fundamental repetition rate of 350 MHz.Mode spacing as wide as 15 GHz with spectrum covered from 690 nm to 710 nm is demonstrated,corresponding to a filter multiple of about 43.The scanning transmission peaks after the F-P cavity with cavity lengths are also simulated numerically,and the results are in agreement with the experiment.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60808007,11078022the Knowledge Innovation Program of Chinese Academy of Sciences under Grant No KJCX-YW-W21.
文摘We demonstrate an octave-spanning Kerr-lens mode-locked Ti:sapphire laser with double-chirped mirrors(DCMs),BaF_(2) wedges and plate,which generates laser pulses in the spectrum range from 600 nm to 1200 nm at-45 dB below the maximum and the duration of 8.5 fs at the repetition rate of 80 MHz.The average output power is 100 mW under 5 W pump power.By carefully adjusting the insertion of BaF_(2) wedges and the optimization position of Ti:sapphire crystal in the cavity,we can obtain the smooth swings in the interferometric autocorrelation trace due to good third-order dispersion compensation.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10874237 and 10804128.
文摘We demonstrate an experimental setup of a tunable ultrafast laser source ty sum-frequency generation (SFG)between a mode-locking Ti:sapphire laser and a Nd:YVO4 laser.The generated wavelength by SFG is tunable from 450nm to 480nm with timing jitter no more than 1 ps.The average output power is over 20mW and the maximum is about 30mW at 457nm.This ultrafast laser is a simple and easy tuning source applied to some pump-probe spectroscopy and ultrafast dynamics experiments.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11074298,91126008,10804128 and 10925421the National Basic Research Program of China under Grant No 2007CB815104the Instrument Developing Project of Chinese Academy of Sciences under Grant No 2010004.
文摘We demonstrate a 100-TW-class femtosecond Ti:sapphire laser running at a repetition rate of 0.1Hz based on a 20TW/10 Hz laser facility (XL-Ⅱ).Pumping the new stage amplifier with a 25J green Nd:glass laser,we successfully improve the laser energy to 3.4J with duration of 29 fs,corresponding to a peak power of 11 7 TW.
基金by the National Natural Science Foundation of China under Grant No 11074298the Instrument Developing Project of the Chinese Academy of Sciences under Grant No 2010004the National Basic Research Program of China under Grant No 2007CB815104.
文摘We present the observation of the additional spectral components between the odd order harmonics in the harmonic spectrum generated from argon gas driven by sub-5-fs laser pulses.The theoretical analysis shows that the asymmetric laser field in both spatial and temporal domains leads to this complicated spectrum structure of high order harmonics.
基金by the National Natural Science Foundation of China under Grant Nos 10905092(Young Scientists Fund),10925421,10974250,and 10935002the National Basic Research Program of China under Grant No 2007CB815102the Fundamental Research Funds for the Central Universities.
文摘A real-time ion spectrometer mainly based on a high-resolution Thomson parabola and a plastic scintillator is designed and developed.The spectrometer is calibrated by protons from an electrostatic accelerator.The feasibility and reliability of the diagnostics are demonstrated in laser-driven ion acceleration experiments performed on the XL-II laser facility.The proton spectrum extrapolated from the scintillator data is in excellent agreement with the CR39 spectrum in terms of beam temperature and the cutoff energy.This real-time spectrometer allows an online measurement of the ion spectra in single shot,which enables efficient and statistical studies and applications in high-repetition-rate laser acceleration experiments.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19854001,10005014 and 19825110the National Hi-Tech ICF Programme。
文摘The effects of laser polarization on super-hot electron (> 100 keV) generation have been studied in the interaction of femtosecond laser light (800 nm, 150 fs, 6 × 10^(15) W·cm^(-2)) with a pre-formed plasma from a slab Cu target. For p-polarized laser pulses, high-energy γ-rays of the energy ~400keV were detected. The electron temperatures deduced from the γ-ray spectra were 66 and 52keV, respectively, in normal and reflective directions of the solid target, and hot electrons were emitted out of the plasma mainly in the normal direction. In contrast, there were nearly no γ-rays >100keV found for s-polarized laser pulses. The hot electron temperature was 26keV and the emission of hot electrons was parallel to the laser field. The superposition of resonant field with electrostatic field excited by escaping electrons may contribute to the high-energy γ-ray or super-hot electron (> 100 keV) generation.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19854001 and 19825110the National High-Tech Inertial Confinement Fusion Committee,and the Pre-research Funds of the China Academy of Engineering Physics。
文摘By observing the fundamental and second harmonic emission from a plasma produced by a 150fs,5mJ laser at 800nm,the electron temperature,the expansion speed and the scalelength of the plasma have been diagnosed.Moreover the polarization of the fundamental and second harmonic emission has been studied.This could be a useful diagnostic for modulation at the critical surface of the plasma.
基金Supported by the National Natural Science Foundation of China under Grant No.19854001the National High Technology ICF Committee under Grant No.416-3.
文摘The γ-rays with energies up to 300keV have been observed from plasmas produced by femtosecond laser pulses at a focused intensity of 5 × 10^(15) W.cm^(-2).μm^(2) irradiating Ta,Mo,and Cu targets.By introducing an 8% prepulse of 70ps before the main pulse,the fraction of high energy γ-ray photons(hv>l00keV)was significantly enhanced relative to low energy photons(hv<100 keV).
