Low temperature enhancement of alignment-induced spectral broadening of femtosecond laser pulses

• 作 者: 王翡 蒋红兵 龚旗煌
• 机 构: Department of Physics & State Key Laboratory for Mesoscopic Physics, Peking University,
• 出 处: Chinese Physics B
• 发表日期: 2014年01期
• 关键词: alignment hollow refractive filled aligned cycle repetition tuning tunable refle

The propagation of femtosecond laser pulses in N2-filled hollow fibers is studied both theoretically and experimentally. The laser pulse aligns the N2 molecules and changes the refractive index, which meanwhile modulates the spectrum of the pulse in turn. The dependence of the spectral modulation on the gas temperature is investigated. We find that both spectral broadening and frequency red-shift are enhanced at low temperature. The degree of enhancement is found to be dependent on the pulse duration. Based on our findings, we propose a method for femtosecond pulse spectral broadening and few-cycle pulse generation via the molecular alignment.

The propagation of femtosecond laser pulses in N2-filled hollow fibers is studied both theoretically and experimentally. The laser pulse aligns the N2 molecules and changes the refractive index, which meanwhile modulates the spectrum of the pulse in turn. The dependence of the spectral modulation on The gas temperature is investigated. We find that both spectral broadening and frequency red-shift are enhanced at low temperature. The degree of enhancement is found to be dependent on the pulse duration. Based on our findings, we propose a method for femtosecond pulse spectral broadening and few-cycle pulse generation via the molecular alignment.