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arXiv 2106.01145physics.opticscond-mat.mtrl-sci
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铌酸锂二次谐波的极化增强

Polaronic Enhancement of Second-Harmonic Generation in Lithium Niobate

Agnieszka L. Kozub, Arno Schindlmayr, Uwe Gerstmann, Wolf Gero Schmidt

摘要:

利用密度泛函理论中的Berry相动态极化公式计算了铌酸锂(LiNbO $_3$)的二阶极化率$χ^{(2)}$。发现缺陷俘获极化子和双极化子强烈增强材料的非线性极化率,特别是如果定位在Nb $_\mathrm{V}$ -V $_{\mathrm{Li}}$缺陷对。这基本上是极化子激发导致弛豫诱导的间隙态的结果。这些水平的占领导致强烈增强的$χ^{(2)}$系数,并允许宏观样品的二次谐波产生的空间和瞬态修改。

英文摘要:

Density-functional theory within a Berry-phase formulation of the dynamical polarization is used to determine the second-order susceptibility $χ^{(2)}$ of lithium niobate (LiNbO$_3$). Defect trapped polarons and bipolarons are found to strongly enhance the nonlinear susceptibility of the material, in particular if localized at Nb$_\mathrm{V}$-V$_{\mathrm{Li}}$ defect pairs. This is essentially a consequence of the polaronic excitation resulting in relaxation-induced gap states. The occupation of these levels leads to strongly enhanced $χ^{(2)}$ coefficients and allows for the spatial and transient modification of the second-harmonic generation of macroscopic samples.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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