Low-frequency atomic stabilization and dichotomy in superintense laser fields from the high-intensity high-frequency Floquet theory
Low-frequency atomic stabilization and dichotomy in superintense laser fields from the high-intensity high-frequency Floquet theory
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DOI：
10.1103/physreva.78.033404
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发表时间：
2008-09-01
影响因子：
2.9
通讯作者：
Stroe, M.
中科院分区：
文献类型：
--
作者：
Gavrila, M.;Simbotin, I.;Stroe, M.
原子与频率为ω的单色激光场相互作用的Floquet问题，很久以前就用“高频Floquet理论”（HFFT）在高ω和任意强度的情况下进行了研究。该理论的两个参数是频率ω和等效于E-0 ω（-2）的经典偏移参数α（0），其中E-0是电场强度。HFFT通过连续迭代求解Floquet系统。迭代过程的收敛性是由ω相对于某些典型的原子激发能足够大的条件保证的。我们现在确定，相同的迭代过程能够处理足够高强度下的低频情况。这导致的结论是，在这种情况下，电离率显示准稳态稳定也在低ω。因此，这个概念并不像人们普遍认为的那样只与高频有关。此外，它建议该理论更合适的名称应该是“高强度，高频Floquet理论”（IHFFT）。我们的一般结果被应用到一个常用的一维（1D）软核势模型，其中可以得到明确的解析结果的准能量和波函数的一般HIHFFT公式。激光脉冲的情况下，这些准稳态结果的相关性指出。
The Floquet problem for the interaction of an atom with a monochromatic laser field of frequency omega was studied long ago for the case of high omega and arbitrary intensity using the "high-frequency Floquet theory'' (HFFT). The two parameters of the theory are the frequency omega and the classical excursion parameter alpha(0) equivalent to E-0 omega(-2), where E-0 is the electric field strength. HFFT solves the Floquet system by successive iterations. Convergence of the iteration procedure was shown to be ensured by the condition that omega be suffiently large with respect to some typical atomic excitation energy. We now establish that the same iteration procedure is capable of handling the case of low frequency at sufficiently high intensity. This leads to the conclusion that in this case the ionization rates display quasistationary stabilization also at low omega. The concept is thus not exclusively related to high frequencies, as widely assumed. In addition, it suggests that a more appropriate designation for the theory should be "high-intensity, high-frequency Floquet theory'' (IHFFT). Our general results are applied to a frequently used one-dimensional (1D) soft-core potential model, for which explicit analytic results can be obtained for the quasienergies and wave functions from the general HIHFFT formulas. The relevance of these quasistationary results for the case of laser pulses is pointed out.