Department of Physics and Astronomy, ‡Department of Electrical and Computer Engineering, and §Department of Materials Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States.
Nano Lett. 2017 Sep 13;17(9):5646-5652. doi: 10.1021/acs.nanolett.7b02524. Epub 2017 Aug 14.
We report a method to electrically detect heating from excitation of propagating surface plasmon polaritons (SPP). The coupling between SPP and a continuous wave laser beam is realized through lithographically defined gratings in the electrodes of thin film gold "bow tie" nanodevices. The propagating SPPs allow remote coupling of optical energy into a nanowire constriction. Heating of the constriction is detectable through changes in the device conductance and contains contributions from both thermal diffusion of heat generated at the grating and heat generated locally at the constriction by plasmon dissipation. We quantify these contributions through computational modeling and demonstrate that the propagation of SPPs provides the dominant contribution. Coupling optical energy into the constriction via propagating SPPs in this geometry produces an inferred temperature rise of the constriction a factor of 60 smaller than would take place if optical energy were introduced via directly illuminating the constriction. The grating approach provides a path for remote excitation of nanoconstrictions using SPPs for measurements that usually require direct laser illumination, such as surface-enhanced Raman spectroscopy.
我们报告了一种通过激发传播表面等离激元 (SPP) 来检测加热的方法。通过在薄膜金“领结”纳米器件的电极中光刻定义的光栅，实现了 SPP 与连续波激光束之间的耦合。传播的 SPP 允许将光学能量远程耦合到纳米线缩颈中。通过器件电导的变化可以检测到缩颈的加热，其中包含了由光栅处产生的热在热扩散和由等离子体耗散在缩颈处产生的热的贡献。我们通过计算建模对这些贡献进行了量化，并证明了 SPP 的传播提供了主要贡献。通过在这种几何形状中传播 SPP 将光学能量耦合到缩颈中，会导致缩颈的温度升高，比直接照射缩颈引入光学能量时升高的幅度小 60 倍。光栅方法为使用 SPP 远程激发纳米缩颈提供了一种途径，用于通常需要直接激光照射的测量，例如表面增强拉曼光谱。
