Nanofabricated Devices For Plasmonic Nanocircuits And Detection Of Plasmonic Thermal Effect

Surface plasmons?SPs?are the collective electron oscillations exists at the metal-dielectric interface that can couple to electromagnetic waves.In recent years plasmonics has received intense research interest because of its potential applications in many fields.These applications are based on the unique properties of SPs,such as local electromagnetic field enhancement and propagation with field confinement beyond the diffraction limit of light.With the rapid developments of nanofabrication techniques in recent years,it becomes possible to fabricate nano devices with high accuracy and quality.The fabrication of plasmonic devices with high controllability and yield by nanofabrication approaches is significant to the application of plasmonic devices.In this thesis,we introduce the nanofabrication of several plasmonic devices including gold nanowires and networks,2D gold nanohole arrays,and dual-layer gold gratings.The applications of gold nanowire networks and nanohole arrays are explored in depth:?1?We fabricate the gold nanowires and networks by electron beam lithography and metal film deposition techniques.The gold nanowire structures are fabricated on quartz substrates without using any adhesion layer but coated with a thin layer of Al₂O₃ film for immobilization.The thermal annealing during the Al₂O₃ deposition process decreases the SP loss.In a Y-shaped nanowire network,the SPs can be routed to different branches by controlling the polarization of the excitation light,and the routing behavior is dependent on the length of the main nanowire.By using two laser beams to excite SPs in a Y-shaped nanowire network,the output intensity can be modulated by the interference of SPs,which can be used to design Boolean logic gates.We experimentally demonstrate that AND,OR,XOR and NOT gates can be realized in three-terminal nanowire networks,and NAND,NOR and XNOR gates can be realized in four-terminal nanowire networks.?2?We fabricate 2D gold nanohole arrays integrated with thermocouples.The 2D gold nanohole arrays support strong SP resonances which can be tuned by the period,the size of nanohole,and the thickness of the metal film.We analyze the absorption spectra of the 2D gold nanohole arrays with different structure parameters.The non-radiative decay of SPs leads to the increase of temperature on the metal structure and this temperature change can be measured by the thermocouple as an electromotive force?EMF?.We measure the EMF of the device under different excitation wavelengths.It matches well with the absorption spectrum of the nanohole array,confirming its origin from the non-radiative decay of SPs.