Abstract A phase-locked laser pair containing two terahertz distributed feedback (DFB) quantum cascade lasers (QCLs) has been realized via evanescent-wave coupling. The mode selection in the laser pair is dominated by the waveguide loss which can be controlled mainly by the ridge width, as well as the width of the gap between the two ridges. A judicious design enables the laser pair to stably operate on the out-of-phase supermode with a side mode suppression ratio (SMSR) of 34 dB, a peak output power of 8.06 mW, and an amplification factor of about 1.72. Due to the significant overlap of the electromagnetic fields caused by the two laser elements, the laser pair is phase-locked even when the two elements are differently biased, confirmed by the measured emission spectra and far-field beam patterns. This work represents a crucial step towards phase-locked arrays for high power single-mode terahertz radiation.

中文翻译：

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通过渐逝波耦合的锁相太赫兹量子级联激光器对

摘要 已经通过渐逝波耦合实现了包含两个太赫兹分布反馈 (DFB) 量子级联激光器 (QCL) 的锁相激光器对。激光器对中的模式选择由波导损耗决定，波导损耗主要由脊宽度以及两个脊之间的间隙宽度控制。明智的设计使激光器对能够在异相超模上稳定运行，边模抑制比 (SMSR) 为 34 dB，峰值输出功率为 8.06 mW，放大系数约为 1.72。由于两个激光元件引起的电磁场的显着重叠，即使两个元件的偏置不同，激光对也是锁相的，测量的发射光谱和远场光束模式证实了这一点。