THz quantum cascade designs for optimized injection

We report two different terahertz (THz) quantum cascade lasers based on bound-to-continuum transitions emitting at 2.8 and 3.8 THz. Novel design approaches have been explored with the purpose of optimizing the electron injection process. Both devices show large current dynamic ranges with output powers of several tens of mW, offering ample scope for future improvements. (C) 2007 Elsevier B.V. All rights reserved.