Transparent conducting oxides as plasmonic component in near infrared (Presentation Recording)

Abstract

The development of new plasmonic materials enables novel optical devices, and they in turn assist in the progress of optical communications. As a result of the significant attention in searching for alternative materials, transparent conducting oxides (TCOs) have been proposed as promising plasmonic compounds at telecommunication wavelengths [1]. They are eminently practical materials because they are CMOS-compatible, can be grown on many different types of substrates, patterned by standard fabrication procedures, and integrated with many other standard technologies. Due to the ability of TCO nanostructures to support strong plasmonic resonance in the NIR, metasurface devices, such as a quarter wave plate, have been demonstrated whose properties can be easily adjustable with post processing such as thermal annealing [2,3]. Additionally, TCOs can be used as epsilon near zero (ENZ) materials in the NIR. From our recent study of the behavior of nanoantennae sitting upon a TCO substrate, we found that TCOs serve as an optical insulating media due to the high impedance of TCOs at the ENZ frequency, enabling emission shaping. Finally, the optical properties of TCOs can be varied by optical or electrical means. Current research is focused on studying the ultrafast carrier dynamics in doped zinc oxide films using pump-probe spectroscopy. We have shown that aluminum doped zinc oxide films can achieve a 40% change in reflection with ultrafast dynamics (<1ps) under a small fluence of 3mJ/cm2. Consequently, TCOs are shown to be extremely flexible materials, enabling fascinating physics and unique devices for applications in the NIR regime.