Narrow-bandgap materials for optoelectronics applications

Narrow-bandgap materials possess the intriguing optical-electric properties and unique structures,which can be widely applied in the field of photonics,energy optoelectronic sensing and biomedicine,etc.Nowadays,the researches on nonlinear optical properties of narrow-bandgap materials have at-tracted extensive attention worldwide.In this paper,we review the progress of narrow-bandgap ma-terials from many aspects,such as background,nonlinear optical properties,energy band structure,methods of preparation,and applications.These materials have obvious nonlinear optical character-istics and the interaction with the short pulse laser excitation shows the extremely strong nonlinear absorption characteristics,which leads to the optical limiting or saturable absorption related to Pauli blocking and excited state absorption.Especially,some of these novel narrow-bandgap materials have been utilized for the generation of ultrashort pulse that covers the range from the visible to mid-infrared wavelength regions.Hence,the study on these materials paves a new way for the advancement of optoelctronics devices.