Surface Plasmon polariton waves are well-known to suffer from high loss where, with a result of this loss causing localized heating of the SPP structure. However, directly measuring optically-induced heating with nanoscale resolution has always been very challenging. Now, using Scanning Thermal Microscopy and NSOM, researchers Boris Desiatov, Ilya Goykhman, and Uriel Levy have characterized both the electromagnetic field and thermal distribution in silicon plasmonic nanotips. The authors used a Multiview 4000 equipped with a Nanonics thermocouple tip - to measure thermal signal as a function of tip position - and a metal-coated NSOM tip to measure the electromagnetic intensity distribution. The use the silicon integrated plasmonic nanoptip device to confine the electromagnetic energy at the silicon tip/metal boundary, resulting in a localized thermal hotspot that they then measure. They find that coupling 10mW of optical power into the waveguide results in a temperature rise of about 15C at the apex of the nanotip compared to ambient temperature; these experimental findings were confirmed with simulations.
This study is important in helping understanding the localized heating of this structure, a major consequence of ohmic loss in these devices.
Published: Nano Letters 2014 14(2) p. 648-652
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