在高速氣體噴流中由凡得瓦力結合而形成的原子團簇聚有十分特殊的性質，因為其內部的密度與固體相同，但是平均密度則是類似於氣體，目前已證實原子團簇可以非常有效率地吸收雷射光，游離形成奈米尺度的高溫高密度電漿球，而放射出高能的電子、離子、與X光。最近更證實其可以做為內層電子躍遷硬X光雷射的增益界質。
在過去利用高強度雷射脈衝驅動原子團簇產生高階諧波的相關研究中，已經證實由雷射激發原子團簇的震盪對高階諧波的產生效率有影響為了進一步了解並控制雷射與原子團簇的交互作用，我們發展出一套以波長810 nm之高強度紅外光雷射脈衝跟波長32.8 nm之軟X光雷射脈衝分別作為激發雷射跟量測雷射的系統，預計觀測原子團簇震盪現象對軟X光雷射吸收率的影響。由於原子團簇震盪會使原子之間距變化，未來希望這些資訊能夠協助我們發展更高效率更短波長的原子團簇內層電子躍遷硬X光雷射。

Atomic cluster is a unique combination of gas and solid phase components. It is normally produced inside a high-pressure gas jet that the atoms are combined through van der Waal’s force. Their solid-like local density and gas-like average density cause individual nanometer clusters efficiently to absorb laser energy, forming highly-charged hot nanoplasmas; to eject keV electrons and MeV ions, and to emit strongly from extreme-ultraviolet to x-ray. It is also demonstrated that cluster jet can be served as the gain medium of the inner-shell hard x-ray laser.
In the past studies of the high-harmonic generation from laser irradiated clusters, it has been proved that laser induced cluster vibration will effect the efficiency of high-harmonic generation. In order to understand and control laser-cluster interaction, we develop an experimental station for pump-probe experiment with IR and x-ray pulses. We use an infrared laser pulse (λ= 810 nm) to induce cluster vibration. After a time delay , we use a soft x-ray pulse (λ= 32.8 nm) to probe the vibration. The absorption of x-ray pulses is measured. We want to find the relationship between cluster vibration and x-ray absorption by observe the variation of x-ray absorption with time delay. As a result of that cluster vibration affects the distance between atoms, understand and control of the vibration may lead us to achieve the efficient inner-shell x-ray lasing from laser irradiated clusters.

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