Buried waveguides in terahertz quantum cascade lasers based on two-dimensional surface plasmon modes

A scheme for buried waveguides in terahertz quantum cascade lasers is demonstrated by combining a surface plasmon mode with ion implantation. The mode is bound to a metal strip deposited on the surface of the device that confines the light in both vertical and lateral directions without any etching requirements. Ion implantation is used to confine the current that selectively pumps the active region. Electrical and optical measurements demonstrate this two-dimensional confinement. Further, by taking advantage of the lower losses and a reduced thermal resistance, laser action is achieved in continuous wave up to 77 K. (C) 2005 American Institute of Physics.