Polarization-dependent optical absorption of MoS 2 for refractive index sensing

Abstract

As a noncentrosymmetric crystal with spin-polarized band structure, MoS 2 nanomaterials have attracts increasing attention in many areas such as lithium ion batteries, flexible electronic devices, photoluminescence and valleytronics. The investigation of MoS 2 is mainly focused on the electronics and spintronics instead of optics, which restrict its applications as key elements of photonics. In this work, we demonstrate the first observation of the polarization-dependent optical absorption of the MoS 2 thin film, which is integrated onto an optical waveguide device. With this feature, a novel optical sensor combining MoS 2 thin-film and a microfluidic structure has been constituted to achieve the sensitive monitoring of refractive index. Our work indicates the MoS 2 thin film as a complementary material to graphene for the optical polarizer in the visible light range, and explores a new application direction of MoS 2 nanomaterials for the construction of photonic circuits.