Contribution of multiple electron trajectories to high-harmonic generation in the few-cycle regime
Contribution of multiple electron trajectories to high-harmonic generation in the few-cycle regime
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DOI：
10.1103/physreva.91.063421
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发表时间：
2015-06-26
影响因子：
2.9
通讯作者：
Niikura, Hiromichi
中科院分区：
文献类型：
--
作者：
Naumov, A. Yu.;Villeneuve, D. M.;Niikura, Hiromichi
我们使用一个数周期的载波包络相位（CEP）稳定的激光系统来产生氩，氖和二氧化碳中的高谐波发射。高次谐波谱由离散谐波阶数组成，其位置作为CEP的函数而移动。在截止谐波附近，峰被两个光子阶分开，并且可以对应于驱动激光频率的偶次或奇次谐波，这取决于CEP的值。在平台区，谐波级仅由一个光子级分开。我们开发了一个简单的模型来预测所观察到的行为。我们使用所观察到的谐波峰作为CEP的函数的依赖性作为测量激光系统的统计CEP波动的方法。测量的均方根波动0.17弧度同意与光学测量。测量CEP稳定性的高次谐波方法的优点是它对激光强度波动的敏感性低于光学方法。
We use a few-cycle, carrier-envelope-phase (CEP) stabilized laser system to generate high-harmonic emission in argon, neon, and carbon dioxide. The high-harmonic spectra consist of discrete harmonic orders whose positions shift as a function of the CEP. Near the cutoff harmonic, the peaks are separated by two photon orders, and can correspond to either even or odd harmonics of the driving laser frequency, depending on the value of the CEP. In the plateau region, harmonic orders are separated by only one photon order. We develop a simple model which predicts the observed behavior. We use the observed dependence of the harmonic peaks as a function of CEP as a method to measure the statistical CEP fluctuations of the laser system. The measured rms fluctuation of 0.17 radians agrees with optical measurements. The high-harmonic approach to measuring CEP stability has the advantage that it is less sensitive to laser intensity fluctuations than are optical methods.