Efficient Terahertz lasers and broadband amplifiers based on QC gain media

Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.Cataloged from PDF version of thesis.Includes bibliographical references (pages 105-110).One of the most important applications for Terahertz (THz) quantum cascade (QC) lasers is to provide compact and powerful frequency-stabilized solid-state sources as local oscillators in heterodyne receivers for astronomical studies. The first part of the thesis is dedicated to the device cavity design, fabrication and characterization of the microstrip antenna coupled third-order distributed feedback QC lasers aimed for 2.060 THz atomic oxygen line. THz travelling-wave QC amplifiers are highly desired to achieve broadband amplification of THz radiation in free space. The second part of the thesis focuses on the development of 4.3 THz travelling-wave QC amplifier by monolithically integrating horn antennas and attaching silicon lenses at the metal-metal waveguide facets.by Xiaowei Cai.S.M