Thermoplasmonic Study of a Triple Band Optical Nanoantenna Strongly Coupled to Mid IR Molecular Mode.
Thermoplasmonic Study of a Triple Band Optical Nanoantenna Strongly Coupled to Mid IR Molecular Mode.
复制标题
与中红外分子模式强耦合的三波段光学纳米天线的热等离子体研究
DOI：
10.1038/srep22227
复制
发表时间：
2016-02-26
影响因子：
4.6
通讯作者：
Lee C
中科院分区：
文献类型：
--
作者：
Hasan D;Ho CP;Pitchappa P;Yang B;Yang C;Lee C
我们报告了对中红外波长 (MW IR) 与分子模式强耦合的三带等离子体纳米天线的首次热研究。混合等离子体结构支持三种空间和光谱变化的共振，其中两种是磁性的，一种是偶极的。通过将结构的等离子体模式与 PMMA 在 5.79μm 处的振动模式耦合来激发杂化模式。模拟和实验中光谱变化之间的定性一致性清楚地表明，电阻加热是偶极峰和磁峰强度变化背后的主要机制。该研究还揭示了随着温度升高耦合模式强度的热不敏感性。我们提出了一种通过模式失谐和表面电流工程来减少耦合模式在高温下的相对强度变化的机制，并证明强度变化小于 9%。随后，我们进行了温度循环测试并研究了 Au-PMMA 复合器件的退化情况。失效条件被认为主要与材料界面的表面化学有关，而不是与纳米图案的变形有关。该研究揭示了强耦合混合模式即使在多次循环下也具有鲁棒性。
We report the first thermal study of a triple band plasmonic nanoantenna strongly coupled to a molecular mode at mid IR wavelength (MW IR). The hybrid plasmonic structure supports three spatially and spectrally variant resonances of which two are magnetic and one is dipolar in nature. A hybridized mode is excited by coupling the structure’s plasmonic mode with the vibrational mode of PMMA at 5.79 μm. Qualitative agreement between the spectral changes in simulation and experiment clearly indicates that resistive heating is the dominant mechanisms behind the intensity changes of the dipolar and magnetic peaks. The study also unveils the thermal insensitivity of the coupled mode intensity as the temperature is increased. We propose a mechanism to reduce the relative intensity change of the coupled mode at elevated temperature by mode detuning and surface current engineering and demonstrate less than 9% intensity variation. Later, we perform a temperature cycling test and investigate into the degradation of the Au-PMMA composite device. The failure condition is identified to be primarily associated with the surface chemistry of the material interface rather than the deformation of the nanopatterns. The study reveals the robustness of the strongly coupled hybridized mode even under multiple cycling.