Measurements of the High Field Optical Nonlinearity and Electron Density in Gases: Application to Filamentation Experiments
Measurements of the High Field Optical Nonlinearity and Electron Density in Gases: Application to Filamentation Experiments
复制标题
气体中高场光学非线性和电子密度的测量：在丝状实验中的应用
DOI：
10.1109/jqe.2012.2187881
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发表时间：
2012
影响因子：
2.5
通讯作者：
H. Milchberg
中科院分区：
文献类型：
--
作者：
J. Wahlstrand;Yu;Yu;Sanjay R. Varma;H. Milchberg
我们讨论了气体中高强度光学非线性的最新实验和计算。对空气成分对电离阈值附近的激光强度的非线性光学响应进行光谱干涉测量。对瞬态双折射测量中泵浦光束和探测光束之间的干涉产生的等离子体光栅引起的相移的计算表明，当泵浦脉冲和探测脉冲具有相同波长时，测量强泵浦脉冲对探测脉冲的交叉相位调制的实验技术对于研究光学非线性是不可靠的。还对灯丝中的电子密度进行干涉测量。测量的峰值电子密度与包含等离子体散焦但不包含高阶克尔项的模型一致。这些技术有望提高对电离阈值和丝化附近非线性光学的定量理解。
We discuss recent experiments and calculations of the high-intensity optical nonlinearity in gases. Spectral interferometry measurements of the nonlinear optical response of air constituents to laser intensities near the ionization threshold are performed. A calculation of the phase shift caused by a plasma grating created by interference between the pump and probe beams in a transient birefringence measurement suggests that experimental techniques measuring cross phase modulation of a probe pulse by a strong pump pulse are unreliable for studying the optical nonlinearity when the pump and probe pulses are of the same wavelength. An interferometric measurement of the electron density in a filament is also performed. The peak elec-tron density measured is consistent with a model that includes plasma defocusing, but not higher-order Kerr terms. These tech-niques promise to improve the quantitative understanding of nonlinear optics near the ionization threshold and filamentation.