Surface-emitting distributed feedback terahertz quantum-cascade phase-locked laser arrays

[摘要] A new approach to achieve high-power, symmetric beam-pattern, single-mode THz emission from metal-metal waveguide quantum-cascade laser is proposed and implemented. Several surface-emitting distributed feedback terahertz lasers are coupled through the connection phase sectors between them. Through carefully choosing the length of phase sectors, each laser will be in-phase locked with each other and thus create a tighter beam-pattern along the phased-array direction. A clear proof of phase-locking phenomenon has been observed and the array can be operated in either in-phase or out-of-phase mode at different phase sector length. The phase sector can also be individually biased to provide another frequency tuning mechanism through gain-induced optical index change. A frequency tuning range of 1:5 GHz out of 3:9 THz was measured. Moreover, an electronically controlled ;;beam steering;; device is also proposed based on the result of this work. This thesis focuses on the design, fabrication and measurement of the surface-emitting distributed feedback terahertz quantum-cascade phase-locked laser arrays.

[发布机构] Massachusetts Institute of Technology