Frequency tuning behaviour of terahertz quantum cascade lasers revealed by a laser beating scheme
Journal article, 2021
In the terahertz frequency range, the commercialized spectrometers, such as the Fourier transform infrared and time domain spectroscopies, show spectral resolutions between a hundred megahertz and a few gigahertz. Therefore, the high precision frequency tuning ability of terahertz lasers cannot be revealed by these traditional spectroscopic techniques. In this work, we demonstrate a laser beating experiment to investigate the frequency tuning characteristics of terahertz quantum cascade lasers (QCLs) induced by temperature or drive current. Two terahertz QCLs emitting around 4.2 THz with identical active regions and laser dimensions (150 μm wide and 6 mm long) are employed in the beating experiment. One laser is operated as a frequency comb and the other one is driven at a lower current to emit a single frequency. To measure the beating signal, the single mode laser is used as a fast detector (laser self-detection). The laser beating scheme allows the high precision measurement of the frequency tuning of the single mode terahertz QCL. The experimental results show that in the investigated temperature and current ranges, the frequency tuning coefficients of the terahertz QCL are 6.1 MHz/0.1 K (temperature tuning) and 2.7 MHz/mA (current tuning) that cannot be revealed by a traditional terahertz spectrometer. The laser beating technique shows potential abilities in high precision linewidth measurements of narrow absorption lines and multi-channel terahertz communications.
Author
WEN GUAN
Chinese Academy of Sciences
ShanghaiTech University
XIAOYU LIAO
Chinese Academy of Sciences
ZIPING LI
Chinese Academy of Sciences
WENJIAN WAN
Chinese Academy of Sciences
KANG ZHOU
Chinese Academy of Sciences
YIRAN ZHAO
Chinese Academy of Sciences
CHENJIE WANG
Chinese Academy of Sciences
XUHONG MA
Chinese Academy of Sciences
Shu Min Wang
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Chinese Academy of Sciences
J. C. CAO
Chinese Academy of Sciences
DONG XU
SIMIC Advanced Micro Semiconductors Co., Ltd.
Chinese Academy of Sciences
JUNWEN ZHANG
Fudan University
NAN CHI
Fudan University
HUA LI
Chinese Academy of Sciences
Optics Express
1094-4087 (ISSN) 10944087 (eISSN)
Vol. 29 14 21269-21279Subject Categories
Atom and Molecular Physics and Optics
Other Physics Topics
Other Electrical Engineering, Electronic Engineering, Information Engineering
DOI
10.1364/OE.427326
PubMed
34265917