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Development of femtosecond time-resolved Raman spectroscopy using stimulated Raman scattering

利用受激拉曼散射开发飞秒时间分辨拉曼光谱

基本信息

批准号：
10640378
负责人：
YOSHIZAWA Masayuki
金额：
$ 1.92万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640378/
关键词：
Femtosecond spectroscopy Stimulated Raman scattering Time-resolved Raman spectroscopy Nonlinear optical effect Photoisomerization DCM dye Charge Transfer Fourier transform limit ラマン分光ラマン増幅

项目摘要

New femtosecond Raman spectroscopy has been developed to investigate ultrafast photoinduced structural changes of materials. Vibrational modes in the transient species are measured by stimulated Raman scattering using a Raman pump pulse with narrow bandwidth and a femtosecond supercontinuum probe pulse. The Raman signal can be measured without slowing the temporal response and broadening the spectrum, because the temporal and spectral resolutions of the new method can be improved independently without restriction of Fourier transform limit. This method can apply to any stimulated Raman scattering, i.e., Raman gain, Raman loss, CARS and CSRS and may also apply to other nonlinear optical spectroscopy. The temporal resolution of 250 fs and the spectral resolution of 25 cmィイD1-1ィエD1 has been obtained simultaneously in this study.Validity of the new system has been demonstrated by the application to the photoisomerization of organic dye. Time-resolved Raman signals in ultrafast trans-cis photoisomerization processes of DCM (4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran) solutions has been investigated. The observed Raman signals are separated to two groups from the temporal dependence and assigned to an intermediate state between trans- and cis-forms and a charge-transfer state in DCM.

新的飞秒拉曼光谱已被开发用于研究材料的超快光致结构变化。使用窄带宽拉曼泵浦脉冲和飞秒超连续谱探测脉冲，通过受激拉曼散射来测量瞬态物质的振动模式。可以在不减慢时间响应和展宽光谱的情况下测量拉曼信号，因为新方法的时间和光谱分辨率可以独立提高而不受傅里叶变换极限的限制。该方法可以应用于任何受激拉曼散射，即拉曼增益、拉曼损耗、CARS和CSRS，并且也可以应用于其他非线性光谱。本研究同时获得了250 fs的时间分辨率和25 cmィイD1-1ィエD1的光谱分辨率。通过在有机染料光异构化中的应用证明了新系统的有效性。研究了 DCM（4-二氰亚甲基-2-甲基-6-对二甲基氨基苯乙烯基-4H-吡喃）溶液超快反式-顺式光异构化过程中的时间分辨拉曼信号。观察到的拉曼信号根据时间依赖性分为两组，并分配给反式和顺式形式之间的中间状态以及 DCM 中的电荷转移状态。