Terahertz laser frequency combs
Terahertz laser frequency combs
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DOI：
10.1038/nphoton.2014.85
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发表时间：
2014-06-01
期刊：
影响因子：
35
通讯作者：
Hu, Qing
中科院分区：
文献类型：
--
作者：
Burghoff, David;Kao, Tsung-Yu;Hu, Qing
太赫兹光可以用来识别许多复杂的分子，但由于缺乏强大的宽带光源，传统上一直未被利用。脉冲激光器可以用来产生宽带辐射，但这种光源体积庞大，平均功率仅为微瓦。相反，虽然太赫兹量子级联激光器是高功率太赫兹辐射的紧凑型半导体源，但它们的窄带发射使它们不适合复杂的光谱学。在这项工作中，我们展示了基于太赫兹量子级联激光器的频率梳，它将高功率激光器与脉冲源的宽带能力联合收割机结合起来。通过充分利用这些激光器可用的量子力学加宽的增益谱，我们可以产生分布在70条激光线上的5 mW太赫兹功率。这种辐射足够强大，可以被肖特基二极管混频器检测到，并将导致紧凑的太赫兹光谱仪。
Terahertz light can be used to identify numerous complex molecules, but has traditionally remained unexploited due to the lack of powerful broadband sources. Pulsed lasers can be used to generate broadband radiation, but such sources are bulky and produce only microwatts of average power. Conversely, although terahertz quantum cascade lasers are compact semiconductor sources of high-power terahertz radiation, their narrowband emission makes them unsuitable for complex spectroscopy. In this work, we demonstrate frequency combs based on terahertz quantum cascade lasers, which combine the high power of lasers with the broadband capabilities of pulsed sources. By fully exploiting the quantum-mechanically broadened gain spectrum available to these lasers, we can generate 5 mW of terahertz power spread across 70 laser lines. This radiation is sufficiently powerful to be detected by Schottky-diode mixers, and will lead to compact terahertz spectrometers.