Extracting complex refractive indices of ultrathin molybdenum oxides using a micro-photonic integrated circuit chip

2D nanomaterials are promising in next-generation miniatured on-chip optical devices. However, their ultra-small thicknesses and limited lateral dimensions hinder the characterization using conventional techniques, especially for complex refractive indices measurement. Here, we propose a silicon photonics-enabled platform to evaluate the complex refractive indices of ultrathin 2D materials in a facile and reliable manner. Ultrathin molybdenum oxides (MoOx) with multiple stoichiometric states are selected as the target 2D material. Wavelength shifts of a Mach-Zehnder interferometer (MZI) device generated from the integrated ultrathin MoOx are recorded for calculating the complex refractive indices. This work demonstrates a highly accurate and reliable approach for measuring the complex refractive index of 2D films with a deviation of less than 5% compared with the theoretical calculation, which possibly assists future advances in 2D materials-enabled optical and photonic applications.

About the presenter

Baoyue Zhang is a Scientific Associate Investigator from RMIT working with CI Michael Fuhrer. Baoyue is researching novel metal oxide nanomaterials as per FLEET’s Enabling Technology A, Anatomically-thin Materials.