Quantum cascade lasers are bright and compact semiconductor lasers that emit light in the mid- to far-infrared spectral region. The use of a closed ring cavity has now set them on the path towards ultrafast pulses.

中文翻译：

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敲响钟声

量子级联激光器是明亮，紧凑的半导体激光器，可在中红外光谱区域发射光。闭环腔的使用现在使它们朝着超快脉冲的方向发展。