Mid-Infrared Photonics Using 2D Materials: Status and Challenges

In recent years, a variety of 2-dimensional (2D) materials including graphene, topological insulators, transition metal dichalcogenides, and black phosphorus have been utilized in photonics and optoelectronics applications. Since the mid-infrared (MIR) region has a significant role in various fields, rapid progress has been made on photonics and optoelectronics applications using 2D materials. Herein, the progress in the photonics devices that exploit the unique properties of 2D materials for a range of MIR applications is summarized, focusing on ultrafast light generation, MIR light modulation, and photodetection. By taking advantage of ultrafast light response, broadband absorption, and high carrier mobility of 2D materials, femtosecond lasers, broadband optical modulators, and high-responsivity photodetectors are achieved. Some perspectives on 2D material-based MIR photonics are highlighted. Due to their MIR bandgaps, small size, high carrier mobility, and easy integration, 2D materials are appealing for MIR photonics applications. Moreover, the availability of an increasingly broad library of 2D materials with variable electronic and optical properties, and the ability to be thinned and restacked into functional and complex assembled structures, enable the development of a highly integrated MIR photonic chip, which will make information technology greener, faster, and lower in energy consumption.