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Beam engineering of quantum cascade lasers
Author(s) -
Yu N.,
Wang Q.,
Capasso F.
Publication year - 2012
Publication title -
laser and photonics reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.778
H-Index - 116
eISSN - 1863-8899
pISSN - 1863-8880
DOI - 10.1002/lpor.201100019
Subject(s) - laser , terahertz radiation , cascade , optoelectronics , plasmon , optics , beam (structure) , wavefront , laser beam quality , collimated light , whispering gallery wave , quantum cascade laser , materials science , physics , laser beams , engineering , chemical engineering
This paper reviews beam engineering of mid‐infrared and terahertz quantum cascade lasers (QCLs), based on two approaches: designer plasmonic structures and deformed microcavities. The plasmonic structures couple laser emission into surface waves and control the laser wavefront in the near‐field, thereby greatly increasing beam collimation or introducing new functionalities to QCLs. The plasmonic designs overall preserve laser performance in terms of operating temperature and power output. The deformed microcavity QCLs operate primarily on whispering‐gallery modes, which have much higher quality factors than other modes, leading to lower threshold current densities. Cavity deformations are carefully controlled to greatly enhance directionality and output power.