Alam T, Wienold M, Lü X, Biermann K, Schrottke L, Grahn H T, Hübers H-W
Opt Express. 2019 Feb 18;27(4):5420-5432. doi: 10.1364/OE.27.005420.
Near-infrared optical excitation enables wideband frequency tuning of terahertz quantum-cascade lasers. In this work, we demonstrate the feasibility of the approach for molecular laser absorption spectroscopy. We present a physical model which explains the observed frequency tuning characteristics by the optical excitation of an electron-hole plasma. Due to an improved excitation configuration as compared to previous work, we observe a single-mode continuous-wave frequency coverage of as much as 40 GHz for a laser at 3.1 THz. This represents, for the same device, a ten-fold improvement over the usually employed tuning by current. The method can be readily applied to a large class of devices.
近红外光激发能够实现太赫兹量子级联激光器的宽带频率调谐。在这项工作中，我们证明了该方法用于分子激光吸收光谱的可行性。我们提出了一个物理模型，该模型通过电子 - 空穴等离子体的光激发来解释所观察到的频率调谐特性。与之前的工作相比，由于激发配置得到了改进，我们观察到对于一台3.1太赫兹的激光器，单模连续波频率覆盖范围高达40吉赫兹。对于同一器件而言，这比通常采用的电流调谐有了十倍的提升。该方法可以很容易地应用于一大类器件。
