Observation of nanoscale opto-mechanical molecular damping as the origin of spectroscopic contrast in photo induced force microscopy.
Observation of nanoscale opto-mechanical molecular damping as the origin of spectroscopic contrast in photo induced force microscopy.
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DOI：
10.1038/s41467-020-19067-3
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发表时间：
2020-11-10
影响因子：
16.6
通讯作者：
Wickramasinghe HK
中科院分区：
文献类型：
--
作者：
Almajhadi MA;Uddin SMA;Wickramasinghe HK
红外光诱导力显微镜 (IR-PiFM) 是一种扫描探针光谱技术，可在纳米 (nm) 尺度上绘制样品形态和化学性质。具有纳米周期性的制造样品（例如嵌段共聚物薄膜的自组装）可以相对容易地通过 IR-PiFM 进行化学表征。尽管 IR-PiFM 取得了成功，但光谱对比度的起源仍不清楚，这阻碍了科学界进行定量测量。在这里，我们通过实验研究了 IR-PiFM 记录振动共振的对比机制。我们表明，测量到的样品光谱信息与振荡悬臂梁中损失的能量直接相关，这是分子在其振动光学共振（称为光机械阻尼）下激发的直接结果。悬臂梁的品质因数和局部样品极化率可以在数学上相关，从而实现定量分析。引入耗散尖端-样品相互作用的基本理论来模拟观察到的光机械阻尼。由于电子传感器速度有限，现有的记录空间和偏振的高维光学成像技术无法检测光子的到达时间。在这里，作者开发了一种单次超快成像模式，以皮秒分辨率记录光速高维事件。
Infrared photoinduced force microscopy (IR-PiFM) is a scanning probe spectroscopic technique that maps sample morphology and chemical properties on the nanometer (nm)-scale. Fabricated samples with nm periodicity such as self-assembly of block copolymer films can be chemically characterized by IR-PiFM with relative ease. Despite the success of IR-PiFM, the origin of spectroscopic contrast remains unclear, preventing the scientific community from conducting quantitative measurements. Here we experimentally investigate the contrast mechanism of IR-PiFM for recording vibrational resonances. We show that the measured spectroscopic information of a sample is directly related to the energy lost in the oscillating cantilever, which is a direct consequence of a molecule excited at its vibrational optical resonance—coined as opto-mechanical damping. The quality factor of the cantilever and the local sample polarizability can be mathematically correlated, enabling quantitative analysis. The basic theory for dissipative tip-sample interactions is introduced to model the observed opto-mechanical damping. Existing high-dimensional optical imaging techniques that record space and polarization cannot detect the photon’s time of arrival due to the limited speeds of electronic sensors. Here, the authors develop a single-shot ultrafast imaging modality to record light-speed high-dimensional events with picosecond resolution.
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影响因子：
17.1
作者：
Gu, Kevin L.;Zhou, Yan;Bao, Zhenan
通讯作者：
Bao, Zhenan
影响因子：
35
作者：
Lu, Feng;Jin, Mingzhou;Belkin, Mikhail A.
通讯作者：
Belkin, Mikhail A.
影响因子：
0.9
作者：
de Melo e Souza, Reinaldo;Kort-Kamp, W. J. M.;Farina, C.
通讯作者：
Farina, C.
DOI：
10.1088/0022-3719/11/20/020
发表时间：
1978-01-01
期刊：
JOURNAL OF PHYSICS C-SOLID STATE PHYSICS
影响因子：
--
作者：
PERSSON, BNJ
通讯作者：
PERSSON, BNJ
影响因子：
3.7
作者：
Olmon, Robert L.;Slovick, Brian;Raschke, Markus B.
通讯作者：
Raschke, Markus B.