Six years after their birth, terahertz quantum-cascade lasers can now deliver milliwatts or
more of continuous-wave coherent radiation throughout the terahertz range—the spectral …

Quantum cascade lasers are unipolar semiconductor lasers covering a wide range of the
infrared and terahertz spectrum. Lasing action is achieved by using optical intersubband …

In the short space of 15years since their first demonstration, quantum cascade lasers have
become the most useful sources of tunable mid-infrared laser radiation. This Letter …

The vast majority of gaseous chemical substances exhibit fundamental vibrational
absorption bands in the mid-infrared spectral region (≈ 2–25 µm), and the absorption of …

Terahertz signals were until recently an almost unexplored area of research due to the
difficulties in generation and detection of electromagnetic fields at these wavelengths …

Coherent sources of mid-infrared (mid-IR) radiation are of great interest for a wide range of
scienti? c and technological applications from spectroscopy and frequency metrology to …

The interband cascade laser differs from any other class of semiconductor laser,
conventional or cascaded, in that most of the carriers producing population inversion are …

The terahertz spectral range (λ= 30–300 µm) has long been devoid of compact, electrically
pumped, room-temperature semiconductor sources,,,. Despite recent progress with terahertz …

Covalent bonding is commonly described by Lewis's theory, with an electron pair shared
between two atoms constituting one full bond. Beginning with the valence bond description …

Terahertz quantum cascade laser (QCL) sources based on intra-cavity difference frequency
generation are currently the only electrically pumped monolithic semiconductor light sources …