Asymmetric single-cycle control of valence electron motion in polar chemical bonds
Asymmetric single-cycle control of valence electron motion in polar chemical bonds
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DOI：
10.1364/optica.414213
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
Y. Morimoto;Y. Shinohara;M. Tani;Bo-Han Chen;K. Ishikawa;P. Baum
中科院分区：
文献类型：
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作者：
Y. Morimoto;Y. Shinohara;M. Tani;Bo-Han Chen;K. Ishikawa;P. Baum
电介质材料对光的响应在微观上由原子环境恢复力下的场循环驱动的电子密度运动来定义。本文应用单周期中红外脉冲驱动具有不对称结构的异核晶体中价电子的非线性运动，并报道了如何将宏观光学响应追溯到沿化学键的对称破缺势中的实空间电子动力学。我们的单周期场是将电子从电负性较弱的元素驱动到电负性较强的元素，还是相反，控制了光滑非线性输出谱的外观，还是偶数和奇数谐波阶的输出谱。晶体角度扫描显示了不对称键的绝对取向。因此，由单个光周期控制的价电荷的定向运动可以用于光谱探索结合势，理解和设计用于非线性光学的新材料，或最终以光的频率处理信息。
A dielectric material’s response to light is microscopically defined by field-cycle-driven motion of electron densities in the restoring forces of the atomic environment. Here we apply single-cycle mid-infrared pulses to drive the nonlinear motion of valence electrons in a heteronuclear crystal with asymmetric structure and report how the macroscopic optical response can be tracked back to the real-space electron dynamics in the symmetry-breaking potential along the chemical bonds. Whether our single-cycle field drives electrons from the less electronegative to the more electronegative element or vice versa controls the appearance of a smooth nonlinear output spectrum or one with even and odd harmonic orders. Crystal angle scans reveal the absolute orientation of the asymmetric bonds. Directional motion of valence charges controlled by a single cycle of light can therefore be used for spectroscopically exploring the binding potential, to understand and design novel materials for nonlinear optics, or to eventually process information at the frequency of light.