Far-Field Polarization Optics Control the Nanometer-Scale Pattern of High-Fluorescence Dissymmetry Emission from Achiral Molecules near Plasmonic Nanodimers
Far-Field Polarization Optics Control the Nanometer-Scale Pattern of High-Fluorescence Dissymmetry Emission from Achiral Molecules near Plasmonic Nanodimers
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DOI：
10.1021/acs.jpcc.3c00467
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
Zechariah Pfaffenberger;Saaj Chattopadhyay;J. Biteen
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文献类型：
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作者：
Zechariah Pfaffenberger;Saaj Chattopadhyay;J. Biteen
像圆二色谱一样的手部光谱学报告了分子的左旋手，但由于传播可见光的波长和分子大小之间的不匹配，通常仅限于高浓度区域。最近的工作表明，在手性等离子体纳米结构附近产生的电磁场可以具有高的光学手性，连接这些长度尺度，并可以通过改变发射方向来诱导非手性染料的高荧光不对称信号。作为迈向单分子手性源的一步，手性等离子体纳米粒子附近的诱导荧光不对称性和表观发射模式必须被量化。在这里，我们测量了非手性染料Cy5.5在手性金纳米二聚体结构附近的诱导荧光不对称性，并用超分辨单分子显微镜绘制了染料的表观发射图案。我们的高灵敏度方法通过仅采样Cy5.5的∼100zeptomoles和从接近金纳米二聚体的Cy5.5测量的荧光不对称因子来量化荧光不对称因子，这些因子比合成的手性荧光分子大两个数量级。我们观察到等离子体金纳米二聚体的模拟光学手性与实验获得的超分辨率表观发射图案之间的空间相关性，并使用入射偏振来控制我们对最亮分子的检测偏差，以采样高电通量的纳米级区域。
Chiroptical spectroscopies like circular dichroism report on the handedness of molecules but are often limited to the high-concentration regime because of the mismatch between the wavelength of propagating visible light and the size of molecules. Recent work has demonstrated that the electromagnetic fields generated near chiral plasmonic nanostructures can have high optical chirality that bridges these length scales and can induce high-fluorescence dissymmetry signals from achiral dyes by redirecting their emission. As a step toward single-molecule chiral sources, the induced fluorescence dissymmetry and apparent emission pattern near chiral plasmonic nanoparticles must be quantified. Here, we measure the induced fluorescence dissymmetry from the achiral dye Cy5.5 near a chiral gold nanodimer structure, and we map out the apparent emission pattern of the dyes using super-resolution single-molecule microscopy. Our high-sensitivity approach quantifies the fluorescence dissymmetry from sampling only ∼100 zeptomoles of Cy5.5 and measures from Cy5.5 near gold nanodimers median fluorescence dissymmetry factors that are 2 orders of magnitude greater than those of synthesized chiral fluorescent molecules. We observe a spatial correlation between the simulated optical chirality about a plasmonic gold nanodimer and experimentally obtained super-resolution apparent emission patterns, and we use the incident polarization to control our detection bias for the brightest molecules to sample nanometer-scale regions of high electric flux.