Study of Intrinsic Localized Modes in Quantum Lattices

量子晶格中本征局域模式的研究

• 批准号: 18340086
• 负责人: SATO Masayuki
• 金额: $ 10.09万
• 依托单位: Kanazawa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18340086/
• 关键词: Intrinsic Localized Modes; Terahertz Spectroscopy; Far-infrared Spectroscopy; Four-wave Mixing Spectroscopy; Laser Spectroscopy; Lattice Vibration; Dielectric materials

A THz nonlinear four wave mixing spectrometer has been developed for studies of intrinsic localized modes of phonon vibration in solids. A FIR laser excited by a TEA laser, a CW FIR laser excited by a carbon dioxide gas laser, a titanium-sapphire laser, Fourier spectrometers have been modified, converted and upgraded. Those equipments have been operated.From theoretical consideration of the time-resolved four wave mixing spectroscopy using above lasers, it has been concluded that the frequency of the FIR laser has to be coincide with a n-th harmonics of a repetition frequency of the titanium-sapphire laser. A cavity length of the titanium sapphire laser must be adjusted to achieve the coincidence of those frequencies. The adjustment of the cavity length is estimated to be within 100mm, and the adjustment with such length will be possible. In this study, we haven't achieved a full development of the four-wave mixing spectrometer with synchronized FIR and titanium-sapphire lasers, partia … More lly because of this unexpected synchronizing problem and because of a failure of an excitation laser of the titanium laser. However, we have been expecting that the development will be completed and four-wave mixing spectra of solids will be measured. It is also expected that problems of phase transition phenomena of solids like dielectrics will be well studied from the point of view of the nonlinear intrinsic localized modes.Intrinsic localized modes based on a 3rd order nonlinearity have been experimentally observed in antiferromagnets and MEMS oscillators. Measurements of four wave-mixing spectra and discovery of sideband resonant structure are very powerful tools in those studies. In this study, we have speculated that the origin of the sideband resonant structure is the fact that the cross nonlinear resonant frequency shift is always larger than the auto nonlinear resonant frequency shift. We have also speculating that the same mechanism keeps the shape of such nonlinear localized modes. We have confirmed that similar sideband structure appears for the intrinsic localized modes based on a 2nd order nonlinearity, that is expected for lattice vibrations of solid lattices. Less

太赫兹非线性四波混合光谱仪已开发用于研究固体中声子振动的固有局域模式，由 TEA 激光器激发的 FIR 激光器、由二氧化碳气体激光器激发的 CW FIR 激光器、钛蓝宝石激光器、傅里叶。通过对上述激光器的时间分辨四波混频光谱的理论考虑，得出了光谱仪的频率。 FIR激光器必须与钛蓝宝石激光器的频率重复的n次谐波一致，必须调整钛蓝宝石激光器的腔长度以实现这些频率的一致。估计腔长度的调整。在100mm以内，这样的长度的调节是可能的。在本研究中，我们还没有实现同步FIR和四波混频光谱仪的全面开发。钛蓝宝石激光器，部分是由于这种意外的同步问题以及钛激光器的激发激光器的故障，但是，我们一直期望开发能够完成，固体的四波混合光谱将会出现。还期望从非线性本征局域模式的角度来很好地研究像电介质这样的固体的相变现象。基于三阶的本征局域模式。非线性已经在反铁磁体和 MEMS 振荡器中被实验观察到，四波混合光谱的测量和边带谐振结构的发现是这些研究中非常有力的工具，我们推测边带谐振结构的起源是事实。交叉非线性谐振频移总是大于自非线性谐振频移我们还推测相同的机制保持了这种非线性局部模式的形状。已经证实，基于二阶非线性的固有局域模式出现了类似的边带结构，这对于固体晶格的晶格振动来说是预期的。

项目成果

Mobile localized excitations in the acoustic spectrum of a nonlinear micromechanical cantilever array

非线性微机械悬臂阵列声谱中的移动局部激励

• 发表时间: 2007
• 期刊: Phys. Rev. Lett 98
• 作者: H. Ueba;B. N. J. Persson;M.Sato and A.J. Sievers
• 通讯作者: M.Sato and A.J. Sievers

Management of localized energy in discrete nonlinear transmission lin es

离散非线性传输线中的局部能量管理

• 发表时间: 2007
• 期刊: EuroPhysics Letters 80
• 作者: M. Sato;S. Yasui;M. Kimura;T. Hikihara;A. J. Sievers
• 通讯作者: A. J. Sievers

Nonlinear Four-wave mixing Spectrometer in THz region

太赫兹区域非线性四波混频光谱仪

• 发表时间: 2008
• 作者: Seri Yamaguchi;Takako Yoshiike;Masayuki Sato
• 通讯作者: Masayuki Sato

Visualization intrinsic localized modes with a nonlinear micromechani cal array

使用非线性微机械阵列可视化固有局部模式

• 发表时间: 2008
• 期刊: Low Temperature Physics(Fizika Nizkih Temper atur) 34
• 作者: M. Sato;A. J. Sievers
• 通讯作者: A. J. Sievers

Visualization intrinsic localized modes with anonlinear micromechanical array

非线性微机械阵列的可视化固有局部模式

• 发表时间: 2008
• 期刊: Low Temperature Physics (Fizika Nizkih Temperatur) 34
• 作者: M. Sato;A. J. Sievers
• 通讯作者: A. J. Sievers