Resonant effect is found in femtosecond laser ablating Pr-Nd glass. When processed with resonant wavelength of 807 nm, resonant ablation efficiency （RAE） with a single pulse can be improved by 45.22%. Furthermore, R...Resonant effect is found in femtosecond laser ablating Pr-Nd glass. When processed with resonant wavelength of 807 nm, resonant ablation efficiency （RAE） with a single pulse can be improved by 45.22%. Furthermore, RAE closely relates to laser intensity. For resonant ablation, RAE is increased significantly when laser intensity 〈0.556×10^14 W/cm^2 at which multiphoton ionization dominates, while it fades away when laser intensity 〉0.556×10^14 W/cm^2 at which tunnel ionization dominates. Besides, it is also found that the ablation depth increases along with the wavelength rise when multiphoton ionization dominates, while the change rule is inversed when tunnel ionization dominates.展开更多
Mechanism of terahertz (THz) pulse generation in gases irradiated by ultrashort laser pulses is investigated theoretically. Quasi-static transverse currents produced by laser field ionization of gases and the longitud...Mechanism of terahertz (THz) pulse generation in gases irradiated by ultrashort laser pulses is investigated theoretically. Quasi-static transverse currents produced by laser field ionization of gases and the longitudinal modulation in formed plasmas are responsible for the THz emission at the electron plasma frequency, as demonstrated by particle-in-cell simulations including field ionization. The THz field amplitude scaling with the laser amplitude within a large range is also discussed.展开更多
The ionization current generated by two-color laser interaction with different gas atoms can produce strong terahertz （THz） emissions. The ionization potential of atoms determines the ionization rate. Thus, THz emis...The ionization current generated by two-color laser interaction with different gas atoms can produce strong terahertz （THz） emissions. The ionization potential of atoms determines the ionization rate. Thus, THz emission from different atoms varies. Particle-in-cell simulations are conducted to investigate the THz emission from He, Ne, Ar, and N. The THz emissions as a function of the laser field are different because the ionization rate and electron speed depend on the laser field and ionization potential.展开更多
基金supported by the National"973"Program of China(No.2011CB013000)the National Natural Science Foundation of China(Nos.91123035,91323301,and 51335011)
文摘Resonant effect is found in femtosecond laser ablating Pr-Nd glass. When processed with resonant wavelength of 807 nm, resonant ablation efficiency （RAE） with a single pulse can be improved by 45.22%. Furthermore, RAE closely relates to laser intensity. For resonant ablation, RAE is increased significantly when laser intensity 〈0.556×10^14 W/cm^2 at which multiphoton ionization dominates, while it fades away when laser intensity 〉0.556×10^14 W/cm^2 at which tunnel ionization dominates. Besides, it is also found that the ablation depth increases along with the wavelength rise when multiphoton ionization dominates, while the change rule is inversed when tunnel ionization dominates.
基金Supported by National Natural Science Foundation of China (10425416, 10674175, 60621063)National High-Tech ICF Com-mittee in China and National Basic Research Program of China (2007CB310406)
文摘Mechanism of terahertz (THz) pulse generation in gases irradiated by ultrashort laser pulses is investigated theoretically. Quasi-static transverse currents produced by laser field ionization of gases and the longitudinal modulation in formed plasmas are responsible for the THz emission at the electron plasma frequency, as demonstrated by particle-in-cell simulations including field ionization. The THz field amplitude scaling with the laser amplitude within a large range is also discussed.
文摘The ionization current generated by two-color laser interaction with different gas atoms can produce strong terahertz （THz） emissions. The ionization potential of atoms determines the ionization rate. Thus, THz emission from different atoms varies. Particle-in-cell simulations are conducted to investigate the THz emission from He, Ne, Ar, and N. The THz emissions as a function of the laser field are different because the ionization rate and electron speed depend on the laser field and ionization potential.
