Direct time-resolved measurement of anharmonic lattice vibrations in ferroelectric crystals
Direct time-resolved measurement of anharmonic lattice vibrations in ferroelectric crystals
复制标题
铁电晶体中非简谐晶格振动的直接时间分辨测量
DOI：
10.1063/1.475293
复制
发表时间：
1997
影响因子：
4.4
通讯作者：
K. Nelson
中科院分区：
文献类型：
--
作者：
C. Brennan;K. Nelson
通过强飞秒脉冲的脉冲受激拉曼散射激发，相干晶格振动被驱动到超过谐波极限的位置。在铁电晶体钽酸锂和铌酸锂随时间变化的响应中，观察到了基晶格振动频率和波矢的高泛音。结果提供了对晶格势能面的非简谐区的可控实验访问，包括离子从它们的初始晶格位置向它们在新的晶格结构中所占据的位置移动的“软”模或“集体反应坐标”路径，即新的磁区取向或晶相。这些观察代表了对材料行为的相干光学控制的重大扩展，并朝着可能诱导合作结构重排的“集体模式选择化学”迈出了一步。
Coherent lattice vibrations are driven beyond the harmonic limit through impulsive stimulated Raman scattering excitation with intense femtosecond pulses. High overtones of the fundamental lattice vibrational frequency and wave vector are observed in the time-dependent responses of the ferroelectric crystals lithium tantalate and lithium niobate. The results provide controlled experimental access to anharmonic regions of lattice potential energy surfaces, including the “soft” mode or “collective reaction coordinate” paths along which ions move from their initial lattice positions toward the positions they occupy in new lattice structures, i.e., new domain orientations or crystalline phases. The observations represent a significant extension of coherent optical control over material behavior, and a step toward “collective mode-selective chemistry” through which cooperative structural rearrangements might be induced.