Ultrafast broadband optical modulation in indium tin oxide/titanium dioxide 1D photonic crystal

Abstract

Photonic crystals can integrate plasmonic materials such as indium tin oxide in their structure. Exploiting indium tin oxide plasmonic properties, it is possible to tune the photonic band gap of the photonic crystal upon the application of an external stimuli. In this work, we have fabricated a one-dimensional multilayer photonic crystal alternating indium tin oxide and titanium dioxide via radiofrequency sputtering and we have triggered its optical response with ultrafast pump-probe spectroscopy. Upon photoexcitation, we observe a change in the refractive index of indium tin oxide. Such an effect has been used to create a photonic crystal that changes its photonic bandgap in an ultrafast time scale. All optical modulation in the visible region, that can be tuned by designing the photonic crystal, has been demonstrated.