The manuscript “Electric tuning and switching of the resonant response of nanoparticle arrays with liquid crystals” by Erik van Heijst and co-workers has been selected as featured article in the last issue of the Journal of Applied Physics. In this article, it is shown how collective plasmonic resonances can be electrically controlled with liquid crystals. This is the first manuscript of the EHCI and ICMS together. Erik van Heijst did his work as part of his graduation research in the Applied Physics and Chemical Engineering department. There he obtained the double degree last year.
Plasmonic resonances in metallic nanoparticles have shown promise for a wide range of applications. This includes nanolasers and extremely sensitive nano-sized biosensors. The field of plasmonics has seen steady improvements toward active control over resonances using the refractive index of the material between nanoparticles.
Scientists designed, constructed and analyzed a tunable device combining nano-particle arrays that support collective surface lattice resonances with liquid crystals. They leveraged the tunability of liquid crystals and the effect of the refractive index of the environment on SLRs. The optical response of the array can be controlled electrically by switching between states in the liquid crystal. The resulting rapid and reversible spectral tuning gives a large degree of control over SLR wavelength.
Narrow collective resonances within arrays are key features in the device’s ability to tune resonance with such control.
The hybrid plasmonic-photonic modes of SLRs exhibit large enhancements of the electric field intensity, despite being delocalized with respect to the individual nanoparticles.
Scientists found the SLR energy shift was less than what was indicated in simulations. This they attribute to the rough surface of the indium tin oxide electrodes. The imperfect alignment of liquid crystals imposed by the nanoparticle structure. Scientists aims to tune the emission of molecules dispersed in the liquid crystal. This then could be coupled to the collective resonance. Then it will ultimately allow a change in crystal orientation.