Abstract-Room temperature broadband terahertz gains in graphene heterostructures based on inter-layer radiative transitions

                            

Linlong Tang^1,2, Jinglei Du^1,a), Haofei Shi^2,b), Dongshan Wei² and Chunlei Du^2,c)
 HIDE AFFILIATIONS
1 Key Laboratory of High Energy Density Physics and Technology, College of Physics and Technology, Sichuan University, Chengdu, 610064, China
2 Chongqing institute of green and intelligent technology, Chinese Academy of Sciences, Chongqing, 401122, China
http://scitation.aip.org/content/aip/journal/adva/4/10/10.1063/1.4900487
a) Electronic mail: dujl@scu.edu.cn
b) Electronic mail: shi@cigit.ac.cn
c) Electronic mail: cldu@cigit.ac.cn

We exploit inter-layer radiative transitions to provide gains to amplify terahertz waves in graphene heterostructures. This is achieved by properly doping graphene sheets and aligning their energy bands so that the processes of stimulated emissions can overwhelm absorptions. We derive an expression for the gain estimation and show the gain is insensitive to temperature variation. Moreover, the gain is broadband and can be strong enough to compensate the free carrier loss, indicating graphene based room temperature terahertz lasers are feasible.