Abstract
By utilizing the phase change properties of vanadium dioxide (VO2), we have demonstrated the tuning of the electric and magnetic modes of split ring resonators (SRRs) simultaneously within the near IR range. The electric resonance wavelength is blue-shift about 73 nm while the magnetic resonance mode is red-shifted about 126 nm during the phase transition from insulating to metallic phases. Due to the hysteresis phenomenon of VO2 phase transition, both the electric and magnetic modes shifts are hysteretic. In addition to the frequency shift, the magnetic mode has a trend to vanish due to the fact that the metallic phase VO2 has the tendency to short the gap of SRR. We have also demonstrated the application of this active metamaterials in tunable surface-enhanced Raman scattering (SERS), for a fixed excitation laser wavelength, the Raman intensity can be altered significantly by tuning the electric mode frequency of SRR, which is accomplished by controlling the phase of VO2 with an accurate temperature control.
Highlights
Plasmonics and metamaterials have attracted numerous interests in imaging, energy harvesting, light manipulation, sensing [1,2,3,4,5]
Many active devices were demonstrated, such as the reconfigurable devices realized by altering the shape and the coupling strength of the structure units [6,7,8], the semiconductor based active devices realized by changing the carrier density of the substrate [9,10,11,12], the liquid-crystal based active devices accomplished by changing the effective index of the liquid-crystal with electric and magnetic field [13, 14], and the electrically controlled active devices [15,16,17]
We observe that the electric mode is blue-shift (~73 nm) while the magnetic mode is red-shift (~126 nm) during the phase transition induced by heating, and the peak shifts of electric and magnetic modes are hysteretic which emerges from the hysteresis nature of the VO2 phase transition
Summary
Plasmonics and metamaterials have attracted numerous interests in imaging, energy harvesting, light manipulation, sensing [1,2,3,4,5]. The phase transition of PCM can introduce significant change of optical and electrical properties, which can be utilized to construct active and tunable device, and the phase transition can be induced by external stimulus such as temperature, light, electric field and magnetic field [24,25,26]. VO2 is a typical and important phase change medium which exhibits insulating-metallic transition at 340 K on a sub picosecond timescale [27]. This kind of transition is initiated by the growing of metallic puddles in the insulating host and the transition is reversible when the stimulus is removed, as such the control of the VO2 phase in real time is possible [28]. We show that we can tune the SERS intensity by controlling the phase of VO2 with a temperature controller, which suggests huge potential as an active sensing device
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
