Coherent sampling of active mode-locked terahertz quantum cascade lasers and frequency synthesis
Coherent sampling of active mode-locked terahertz quantum cascade lasers and frequency synthesis
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DOI：
10.1038/nphoton.2011.49
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发表时间：
2011-05-01
期刊：
影响因子：
35
通讯作者：
Davies, A. Giles
中科院分区：
文献类型：
--
作者：
Barbieri, Stefano;Ravaro, Marco;Davies, A. Giles
太赫兹量子级联激光器是紧凑的电泵浦半导体激光源，能够以连续波提供数十毫瓦的功率。在这里，我们表明，这些设备可以通过调制它们的偏置电流与射频合成器在一个制度的主动锁模。通过将量子级联激光器重复率和载波频率锁相到锁模飞秒光纤激光器的重复率的谐波，可以检测所发射的脉冲串。这种技术允许太赫兹电场的相干采样，表明太赫兹脉冲是变换限制的。此外，我们的技术允许控制量子级联激光器的载波包络相移。
Terahertz quantum cascade lasers are compact, electrically pumped semiconductor laser sources that are capable of delivering tens of milliwatts of power in continuous wave. Here, we demonstrate that these devices can be operated in a regime of active mode-locking by modulating their bias current with a radiofrequency synthesizer. Detection of the emitted pulse train is made possible by phase-locking the quantum cascade laser repetition rate and carrier frequency to a harmonic of the repetition rate of a mode-locked femtosecond fibre laser. This technique allows coherent sampling of the terahertz electric field, showing that the terahertz pulses are transform-limited. In addition, our technique allows control of the carrier-envelope phase shift of the quantum cascade laser.