Assessing the degree of heating present when a metal nanoparticle is trapped in an optical tweezers is critical for its appropriate use in biological applications as a nanoscale force sensor. Heating is necessarily present for trapped plasmonic particles because of the non-negligible extinction which contributes to an enhanced polarisability. We present a robust method for characterising the degree of heating of trapped metallic nanoparticles, using the intrinsic temperature dependence of the localised surface plasmon resonance (LSPR) to infer the temperature of the surrounding fluid at different incident laser powers. These particle specific measurements can be used to infer the rate of heating and local temperature of trapped nanoparticles. Our measurements suggest a considerable amount of a variability in the degree of heating, on the range of 414–673 K/W, for different 100 nm diameter Au nanoparticles, and we associated this with variations in the axial trapping position.
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机译：评估将金属纳米粒子捕获在光镊中时出现的加热程度对于将其适当地用作生物学应用中的纳米力传感器至关重要。由于不可忽略的消光会导致极化率增强，因此必须对捕获的等离激元粒子进行加热。我们提出了一种用于表征捕获的金属纳米颗粒加热程度的可靠方法，使用局部表面等离子体共振（LSPR）的固有温度依赖性来推断在不同入射激光功率下周围流体的温度。这些特定于颗粒的测量可用于推断被捕获的纳米颗粒的加热速率和局部温度。我们的测量结果表明，对于不同的100 nm直径的Au纳米粒子，加热程度在414–673 K / W范围内存在相当大的变化，我们将此与轴向俘获位置的变化联系在一起。
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