Nonlocal nonlinear phononics
Nonlocal nonlinear phononics
复制标题
非局部非线性声学
作者：
M. Henstridge;M. Forst;Edward L. Rowe;M. Fechner;A. Cavalleri
非线性声子学依赖于红外活性晶格振动的共振光激发来诱导固体中的目标结构变形。这种形式的动态晶体结构设计已被应用于控制许多复杂固体的功能特性，包括磁性材料，超导体和铁电体。然而，到目前为止，声子已被限制在协议中，结构变形发生在光激发体积，有时会导致不必要的加热。在这里，我们扩展非线性声子传播极化激元，空间分离的功能响应从光学驱动器。我们使用中红外光脉冲共振驱动铁电铌酸锂表面的声子。时间分辨的受激拉曼散射表明，铁电极化在样品的整个50 μm深度上都降低了，远远超过了倏逝声子场的微米深度。我们将这种效应归因于驱动模式和传播到材料中的极化激元之间的非谐耦合。对于高激发振幅，我们达到一个制度，其中铁电极化反转，所揭示的所有极性模式的拉曼张量系数的符号变化。非线性声子学是一种在固体中产生瞬态结构变化的方法，但其效果仅限于光激发区域。现在，耦合到传播的极化激元允许非线性声子驱动非局部响应。
Nonlinear phononics relies on the resonant optical excitation of infrared-active lattice vibrations to induce targeted structural deformations in solids. This form of dynamical crystal structure design has been applied to control the functional properties of many complex solids, including magnetic materials, superconductors and ferroelectrics. However, phononics has so far been restricted to protocols in which structural deformations occur within the optically excited volume, sometimes resulting in unwanted heating. Here, we extend nonlinear phononics to propagating polaritons, spatially separating the functional response from the optical drive. We use mid-infrared optical pulses to resonantly drive a phonon at the surface of ferroelectric LiNbO3. Time-resolved stimulated Raman scattering reveals that the ferroelectric polarization is reduced over the entire 50 µm depth of the sample, far beyond the micrometre depth of the evanescent phonon field. We attribute this effect to the anharmonic coupling between the driven mode and a polariton that propagates into the material. For high excitation amplitudes, we reach a regime in which the ferroelectric polarization is reversed, as revealed by a sign change in the Raman tensor coefficients of all the polar modes. Nonlinear phononics is a method for creating transient structural changes in solids, but its effect is limited to the region of optical excitation. Now, coupling to a propagating polariton allows nonlinear phononics to drive a nonlocal response.
影响因子：
4.4
作者：
Lee, SY;Zhang, DH;Mathies, RA
通讯作者：
Mathies, RA
影响因子：
64.8
作者：
Mankowsky, R.;Subedi, A.;Cavalleri, A.
通讯作者：
Cavalleri, A.