Microstrip-antenna-coupled distributed feedback terahertz quantum-cascade lasers
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89930E.pdf
Description
Published version
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1.14 MB
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Unknown
Checksum (MD5)
546de9b75b4e74eed4624ec5ee097fab
Author(s)
Kao, Tsung-Yu
Cai, Xiaowei
Hu, Qing
Reno, John L.
Date Issued
December 2013
Publisher
SPIE
Citation
Kao, Tsung-Yu, Cai, Xiaowei, Hu, Qing and Reno, John L. 2013. "Microstrip-antenna-coupled distributed feedback terahertz quantum-cascade lasers."
Version
Final published version
Abstract
By introducing coupled microstrip antennas on THz Distributed Feedback (DFB) Quantum Cascade Lasers (QCLs), the radiation efficiency of each feedback aperture is greatly enhanced. Single mode emission ∼3 THz from a 31-period antenna-coupled third-order DFB laser yields ∼4 times improvement in output power comparing with a corrugated thirdorder device fabricated on the same gain medium. This 31-period device has ∼15×25° beam divergence and 4 mW pulsed power (4%) at 10 K with maximum lasing temperature (Tmax) at 134 K (pulsed). When phase matching condition is met, emissions from 81 apertures (4-mm long) are coherently combined to form a narrow beam with 12.5° divergence. Further experiment demonstrated the new device at 4 THz (25-period, ∼18 μm×1-mm long. The 4 THz device reaches >8 mW pulsed power (10%) at 12 K with Tmax109 K (pulsed) and >77 K (cw). The slope efficiency is 450 mW/A with 0.57% wall-plug. It is worth pointing out although the antennas would be excited differently, similar enhancement in out-coupling efficiency can also be observed in second-order surface-emitting THz DFB lasers. Begin the abstract two lines below author names and addresses.. © 2014 SPIE.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Research Laboratory of Electronics
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Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1117/12.2036604
