Phase locking of a 1.5 Terahertz quantum cascade laser and use as a local oscillator in a heterodyne HEB receiver
Phase locking of a 1.5 Terahertz quantum cascade laser and use as a local oscillator in a heterodyne HEB receiver
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DOI：
10.1364/oe.17.001159
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发表时间：
2009-02-02
期刊：
影响因子：
3.8
通讯作者：
Faist, J.
中科院分区：
文献类型：
--
作者：
Rabanus, D.;Graf, U. U.;Faist, J.
我们证明了第一次关闭的电子锁相环的连续波量子级联激光器（QCL）在1.5太赫兹。QCL在封闭循环低温冷却器中运行。我们实现了优于100 Hz的频率稳定性，受限于频谱分析仪的分辨率带宽。PLL电子器件利用从热电子测辐射热计（HEB）获得的中频（IF），该热电子测辐射热计被下变频到125 MHz的PLL IF。通过QCL的偏置电压实现纵模的粗选和精调。在QCL腔模式内，自由运行的QCL示出约5MHz的频率波动，PLL电路能够经由QCL增益材料的斯塔克位移来控制该频率波动。结果表明，与温度相关的调谐是非线性的，量级为-16 MHz/K。此外，我们已经使用QCL作为本地振荡器（LO）泵浦HEB和执行，再次在1.5 THz的第一次，外差实验，并获得1741 K的接收机噪声温度。(C)2009年美国光学学会
We demonstrate for the first time the closure of an electronic phase lock loop for a continuous-wave quantum cascade laser (QCL) at 1.5 THz. The QCL is operated in a closed cycle cryo cooler. We achieved a frequency stability of better than 100 Hz, limited by the resolution bandwidth of the spectrum analyser. The PLL electronics make use of the intermediate frequency ( IF) obtained from a hot electron bolometer (HEB) which is downconverted to a PLL IF of 125 MHz. The coarse selection of the longitudinal mode and the fine tuning is achieved via the bias voltage of the QCL. Within a QCL cavity mode, the free-running QCL shows frequency fluctuations of about 5 MHz, which the PLL circuit is able to control via the Stark-shift of the QCL gain material. Temperature dependent tuning is shown to be nonlinear, and of the order of -16 MHz/K. Additionally we have used the QCL as local oscillator (LO) to pump an HEB and perform, again for the first time at 1.5 THz, a heterodyne experiment, and obtain a receiver noise temperature of 1741 K. (C) 2009 Optical Society of America