Abstract | Quantum cascade (QC) lasers1 are light sources based on optical transitions between quantized states of the conduction band in semiconductor nanostructures. These devices emit in the mid-infrared spectral region, which is known as the molecular fingerprint region, because many chemical and biological species have their telltale absorption features at these wavelengths. This spectral range is characterized by the lack of convenient laser sources of ultrashort pulses. On the other hand, these sources would be quite desirable for several applications, ranging from time-resolved spectroscopy to coherent control. Recently, we demonstrated the generation of picosecond mid-infrared pulses with gain-switched and actively mode-locked QC lasers. |
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