Photothermal therapy assisted by plasmonic nanostructure relies on the absorption of light energy by the metallic nanoparticle. The manifestation of a rational use of plasmonic-assisted superficial laser thermal therapy procedures requires the analyses of the thermoplasmonic behavior of colloidal nanostructures in random orientation. A quantitative analysis of orientation effect on optically heating metallic nanostructures still unrevealed. Here, we evaluate the thermal properties of metallic nanoparticles (SiO₂/Au core-shell particles, Au nanotriangles, Au nanorods, and Au nanocages) irradiated by polarized light. We perform 3D full-wave field analysis to compare absorption properties and temperature rise of these nanoparticles as a function of the nanostructure orientation with respect to applied field polarization. The analysis shows a major variation in joule number of asymmetrical nanostructures (up to 50%) due to orientation effects, which may limit its performance on colloidal photothermal applications. In contrast, the high degree of rotational symmetry of core-shell nanoparticles and nanocages provide greater potential in thermal-assisted phototherapy applications, as their absorption is largely independent (less than 2%) of their orientation in colloid. Our computational results establish new insights for the use of gold nanocages, as a high performance plasmonic structure for thermal applications with colloidal samples.

中文翻译：

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取向对近红外胶体金纳米结构的等离子加热的影响

由等离子体纳米结构辅助的光热疗法依赖于金属纳米颗粒对光能的吸收。合理使用等离子辅助浅表激光热疗程序的表现要求分析胶体纳米结构在随机取向下的热等离子行为。尚未公开对光学加热金属纳米结构的取向效应的定量分析。在这里，我们评估了金属纳米颗粒（SiO ₂/ Au核壳粒子，Au纳米三角形，Au纳米棒和Au纳米笼）受到偏振光的照射。我们进行3D全波场分析，以比较这些纳米颗粒的吸收特性和温度升高，该吸收特性和温度升高是相对于所施加的场极化的纳米结构取向的函数。分析显示，由于取向效应，不对称纳米结构的焦耳数（高达50％）有很大变化，这可能会限制其在胶体光热应用中的性能。相比之下，核壳纳米粒子和纳米笼的高度旋转对称性在热辅助光疗应用中提供了更大的潜力，因为它们的吸收在很大程度上与胶体中的取向无关（小于2％）。我们的计算结果为金纳米笼的使用提供了新的见解，