Förster resonance energy transfer (FRET) is ubiquitous in optical processes in the natural world. A methodology is proposed that uses an optical force to control its efficiency without contact in an aqueous solution of a thermo‐responsive polymer, polyvinyl methyl ether (PVME). Focusing irradiation of a near infrared laser beam into the solution results in the formation and trapping of a single polymer droplet. The polymer concentration in the droplet is controllable by changing the optical force from the laser light is shown. The polarity inside the droplet decreases with increasing the optical force. When small amounts of dye molecules, D (energy donor) and A (energy accepter), are dissolved in the polymer solution, D and A are absorbed (extracted) into the droplet. The concentrations of D and A are controllable by the optical force. Based on this mechanism, FRET between D and A is induced successfully, and can control the FRET efficiency. Finally, the modulation of fluorescence color of the droplet from blue, green, yellow, to an orange color is demosntrated simply by changing the optical force. The concept and technique are unique and will open a new channel to develop droplet chemistry and photochemistry.

中文翻译：

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通过光力控制福斯特共振能量转移

福斯特共振能量转移 (FRET) 在自然界的光学过程中无处不在。提出了一种方法，在热响应聚合物聚乙烯甲基醚（PVME）的水溶液中使用光学力来控制其效率，而无需接触。将近红外激光束聚焦照射到溶液中会形成并捕获单个聚合物液滴。显示了通过改变激光的光学力可以控制液滴中的聚合物浓度。液滴内部的极性随着光学力的增加而降低。当染料分子含量较少时，D（能量捐赠者）和A（能量受体），溶解在聚合物溶液中，D和A被吸收（提取）到液滴中。的浓度D和A可以通过光力来控制。基于这种机制，FRET之间D和A诱导成功，并且可以控制FRET效率。最后，简单地通过改变光学力就演示了液滴荧光颜色从蓝色、绿色、黄色到橙色的调制。该理念和技术独特，将为液滴化学和光化学的发展开辟新的途径。