We demonstrate the electrical beat note analysis and radio frequency （RF） injection locking of a continuous wave （cw） terahertz quantum cascade laser （QCL） emitting around 3 THz （-100 μm）. In free running the...We demonstrate the electrical beat note analysis and radio frequency （RF） injection locking of a continuous wave （cw） terahertz quantum cascade laser （QCL） emitting around 3 THz （-100 μm）. In free running the beat note frequency of the QCL shows a shift of ~180 MHz with increasing drive current. The beat note, modulation response, injection pulling, and terahertz emission spectral characteristics in the different current regimes Ⅰ, Ⅱ, and Ⅲ are investigated. The results show that in the current regime I close to the laser threshold we obtain a narrower beat note and flat response to the RF modulation at the cavity round trip frequency. The pulling effect and spectral modulation measurements verify that in the current regime I the RF injection locking is more ef- ficient and a robust tool to modulate the mode number and mode frequency of terahertz QCLs.展开更多
基金supported by the“Hundred-Talent”Program of Chinese Academy of Sciencesthe National Natural Science Foundation of China(No.61575214)+2 种基金the Shanghai Municipal Commission of Science and Technology(Nos.14530711300,15560722000,and 15ZR1447500)the National 973 Program of China(No.2014CB339803)the Major National Development Project of Scientific Instrument and Equipment(No.2011YQ150021)
文摘We demonstrate the electrical beat note analysis and radio frequency （RF） injection locking of a continuous wave （cw） terahertz quantum cascade laser （QCL） emitting around 3 THz （-100 μm）. In free running the beat note frequency of the QCL shows a shift of ~180 MHz with increasing drive current. The beat note, modulation response, injection pulling, and terahertz emission spectral characteristics in the different current regimes Ⅰ, Ⅱ, and Ⅲ are investigated. The results show that in the current regime I close to the laser threshold we obtain a narrower beat note and flat response to the RF modulation at the cavity round trip frequency. The pulling effect and spectral modulation measurements verify that in the current regime I the RF injection locking is more ef- ficient and a robust tool to modulate the mode number and mode frequency of terahertz QCLs.
