Black phosphorus: device and application

In the advancement of photonics technologies, all-optical systems are highly demanded in ultrafast photonics, signal processing, optical sensing, and communication. All-optical devices are the core elements to visualize the next generation of photonics integration systems and optical interconnection. As a result, the venture of new optoelectronic materials that able to cater to different optical properties is a highlighted research direction in photonics technologies. The emerging of two-dimensional (2D) black phosphorus (BP) has provided great potential in the evolution of photonics technologies. Owing to the optical properties of 2D materials, including unique mechanical, electronic, photonic, and thermal anisotropy, tunable and direct bandgap, and high mobility of an energy bandgap, third-order nonlinearity, nonlinear absorption, and the thermo-optics coefficient can be a tailor for different types of optical applications. Since the past decade, the explorations of 2D materials in photonics applications have to extend to all-optical modulators, all-optical switches, and all-optical wavelength converters that covered visible and near-infrared wavelength range. Herein, we review all-optical devices based on the 2D layer materials, especially BP from principle, synthesis, and its device and application. Finally, we commented on the perspectives and challenges on the future of the potential applications of 2D materials.