Rydberg原子在半週期脈波下的古典一維軌跡研究

Abstract

近年來由Jones等人在實驗室中，所製造出的強超短脈波––具有單偏 極化的半個光 學週期之電場––受到許多注意與討論。因為脈波時間 與激發態電子的古典週期相當，我 們希望瞭解其與原子作用的行為與傳 統雷射之異同。 本論文由古典力學的理論，來探 討一高激發態的氫 原子，受到此一脈波作用後的游離反應。為解決古典電子模型中的原點 位能之發散情形，我們採用了 Soft Coulomb potential 的形式。我們討 論了在此種類型 的位能條件下，對電子游離機率之影響。並且，所採用 的為 Monte-Carlo 軌跡數值方法 。 我們最後可以發現，在這些條 件下，電子的游離機率並未在強場下產生所謂的穩定 現象。並由相空間 圖形中，發現電子的起始條件與產生游離現象的關係。 Recently, Jones et al. studied the interaction of Rydberg atoms with the Half-cycle pulse(HCP). The pulse duration can be made to match the classical Kepler period of the electron. We will study the classical behavior of the atom under the HCP rather than traditional laser pulse, which is usually hundreds optical cycle in duration. This thesis discuss about the ionizationof a Rydberg hydrogen atom under HCP in the classical regime. To avoid the singularity at the origin of the classical potential, we use a model which isreferred as "soft Coulomb potential". We also discuss the influence of ionization probabilities by Monte-Carlo trajectory method with different potential model conditions. We find out that, under such conditions, anomalousionization stablization in strong fields does not showup. However, in phase space diagrams, we conclude the thesis by the relationship between the initial conditions and ionization of a Rydberg atom.