Temperature Elevation and Fluid Convection Under Optical Trapping Condition as Revealed by Fluorescence Correlation Spectroscopy
Temperature Elevation and Fluid Convection Under Optical Trapping Condition as Revealed by Fluorescence Correlation Spectroscopy
复制标题
荧光相关光谱揭示光捕获条件下的温度升高和流体对流
DOI：
10.1117/1.jnp.13.012504
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发表时间：
2018
影响因子：
1.5
通讯作者：
Kenji Setoura; Keisuke Fujita; Syoji Ito*; Hiroshi Miyasaka*
中科院分区：
文献类型：
--
作者：
Kenji Setoura;Tetsuro Tsuji;Syoji Ito;Satoyuki Kawano;Hiroshi Miyasaka;Kenji Setoura; Keisuke Fujita; Syoji Ito*; Hiroshi Miyasaka*
在强光照射下，由于光热转换，物质的温度升高。光热效应有时是光学操作中的一个重要问题，通常需要强光场。因此，定量评估光照射下的局部温度可以为光学操作提供不可或缺的信息。在以前的工作中，我们已经应用荧光相关光谱（FCS）监测温度下的光捕获条件下的水，乙醇和乙二醇。我们指出，荧光染料的扩散时间的分析可以提供有关的温度的基础上的溶剂的粘度的信息。在目前的工作中，FCS测温适用于七种溶剂，包括脂肪族伯醇，以检查该方法的普遍适用性。为了验证实验结果，数值模拟的基础上进行二维热传导在稳态。温度场的数值计算结果与实验数据吻合较好，证明FCS测温法适用于一般溶剂。此外，我们还对溶剂中的速度场进行了数值模拟，以评估在典型的光阱条件下，在光强度为10MW cm− 2时自然对流的贡献。结果表明，自然对流对传质的贡献是不可忽略的。
Temperature of matter increases under intense photoirradiation owing to photothermal conversion. The photothermal effect is sometimes a significant issue in optical manipulation usually requiring intense optical fields. Quantitative evaluation of local temperature under photoirradiation can, therefore, provide indispensable information for optical manipulation. In a previous work, we have applied fluorescence correlation spectroscopy (FCS) to monitor the temperature under the optical trapping condition in water, ethanol, and ethylene glycol. We pointed out that analyses of diffusion time of fluorescent dyes could provide information about temperature on the basis of temperature-dependent viscosities of the solvents. In the present work, the FCS thermometry was applied to seven solvents including primary aliphatic alcohols, to examine universal applicability of the method. To verify the experimental results, numerical simulations were performed on the basis of two-dimensional heat conduction at a stationary state. The numerical results on the temperature field satisfactorily reproduced the experimental data, proving that the FCS thermometry is applicable to ordinary solvents. In addition, we also performed numerical simulations on velocity fields in the solvent, to evaluate contribution of natural convection under typical optical trapping condition at light intensity of ∼MW cm− 2. It was revealed that the contribution of the natural convection is not negligible for mass transfer in the solvents.