The magnetic response of natural materials at optical frequencies is very weak, which is due to electronic spin states which diminish at high frequencies. That is why only the electric component of light is directly controlled in conventional photonic devices. Metamaterials, i.e. electromagnetic composite structures with properties engineered at the nanoscale, have opened a way to transcend this limit by designing nanostructured materials with artificial magnetic properties. Today the vast majority of photonic structures exhibiting artificial magnetism in the visible frequency range contain metallic elements, so that strong dissipative losses have retarded their practical applications.
Resonant dielectric nanostructures makes a new twist on light-matter interaction. We have recently demonstrated that subwavelength particles made of high-dielectric materials exhibit very strong magnetic response in visible range. Nanophotonic structures composed of dielectric resonators can exhibit many of the same features as plasmonic nanostructures and even outperform them, including superscattering, near-field enhancement, high-frequency magnetism and others. One of the most successful application is the superior performance of hybrid and all-dielectric nanoantennas for effective control of light emission from localized sources. Strong near-field enhancement in resonant dielectric nanostructures implies that strong nonlinear phenomena can be expected in the nonlinear optical response of high-index dielectric nanoparticles. Recently, we have observed enhanced third-order optical nonlinearities of silicon nanodisks at the vicinity of the magnetic dipole resonances pumped by femtosecond laser pulses. The efficiency of the conversion is enhanced by two orders of magnitude with respect to the unstructured bulk silicon slab. These results demonstrate a possibility to establishing a novel efficient platform of nanoscale resonant nonlinear optical media driven by optically-induced magnetic response of low-loss high-index nanoparticles.
Dr Andrey Miroshnichenko obtained his PhD in 2003 from the Max-Planck Institute for Physics of Complex Systems in Dresden, Germany. In 2004 he moved to Australia to join the Nonlinear Physics Centre at ANU. During this time Dr. Miroshnichenko made fundamentally important contributions to the field of photonic crystals and bringing the concept of the Fano resonances to photonics. In 2007 Dr. Miroshnichenko was awarded by APD Fellowship from the Australian Research Council. It allowed him to initiate the research on a new class of tunable photonic structures infiltrated with liquid crystals. In 2011 he was awarded by Future Fellowship from the Australian Research Council. The current topics of his research are nonlinear nanophotonics, resonant interaction of light with nanoclusters, including optical nanoantennas and metamaterials.
Refreshments will be held in the Tea Room after the Seminar (around 5pm)