Fully automated dual-frequency three-pulse-echo 2DIR spectrometer accessing spectral range from 800 to 4000 wavenumbers
Fully automated dual-frequency three-pulse-echo 2DIR spectrometer accessing spectral range from 800 to 4000 wavenumbers
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DOI：
10.1063/1.4892480
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发表时间：
2014-08-01
影响因子：
1.6
通讯作者：
Rubtsov, Igor V.
中科院分区：
文献类型：
--
作者：
Leger, Joel D.;Nyby, Clara M.;Rubtsov, Igor V.
设计和制造了一种新型的双频二维红外仪，它允许以全自动的方式对800~4000 cm(-1)光谱范围内的任何交叉峰进行三脉冲外差回波测量。该仪器通过光谱干涉测量、相位循环和精确到类似70as的闭环相位稳定相结合，实现了卓越的灵敏度。在800次激光激发下，记录到了小于10(-4)cm(-1)的强羰基伸缩模式的非谐性。新设计的稳相方案允许调谐中红外(m-IR)脉冲的偏振，从而支持振动跃迁偶极子之间的角度测量。自动调频是通过对每个m-IR波束实施波束方向稳定方案来实现的，提供了优于50µrad的波束稳定性，以及在样品处设置m-IR波束的相位匹配几何的新方案。与不理想的相位匹配条件和对准有关的交叉峰值幅度的误差被发现在20%的水平。该仪器可供超快光谱学的非专业人员使用。(C)2014 AIP出版有限责任公司。
A novel dual-frequency two-dimensional infrared instrument is designed and built that permits three-pulse heterodyned echo measurements of any cross-peak within a spectral range from 800 to 4000 cm(-1) to be performed in a fully automated fashion. The superior sensitivity of the instrument is achieved by a combination of spectral interferometry, phase cycling, and closed-loop phase stabilization accurate to similar to 70 as. The anharmonicity of smaller than 10(-4) cm(-1) was recorded for strong carbonyl stretching modes using 800 laser shot accumulations. The novel design of the phase stabilization scheme permits tuning polarizations of the mid-infrared ( m-IR) pulses, thus supporting measurements of the angles between vibrational transition dipoles. The automatic frequency tuning is achieved by implementing beam direction stabilization schemes for each m-IR beam, providing better than 50 mu rad beam stability, and novel scheme for setting the phase-matching geometry for the m-IR beams at the sample. The errors in the cross-peak amplitudes associated with imperfect phase matching conditions and alignment are found to be at the level of 20%. The instrument can be used by non-specialists in ultrafast spectroscopy. (C) 2014 AIP Publishing LLC.