Amplification of terahertz radiation in quantum cascade structures

We explore the use of quantum cascade structures as amplifiers for terahertz radiation. For this purpose, two section devices were fabricated, in which the output from a nu similar to 2.3 THz laser section is amplified in a subsequent stage. For relatively short devices we obtain an amplification of 1.5x, in good agreement with the calculated level. Based on these results we predict that amplifications of up to 13 dB could be obtained for such structures using increased amplifier lengths of a few millimeters.(C) 2007 American Institute of Physics.