Conventional Quantum Cascade (QC) lasers are based on intersubband transitions in repeated stages of precisely engineered quantum wells, with one electron emitting at most one photon in each stage. Here, we report on a same-wavelength cascaded-transition (SWCT) QC structure, with two subsequent optical transitions emitting at the same wavelength (λ ∼ 14.2 μm) in each stage. This SWCT QC gain medium was inserted between two conventional QC stacks, also at ∼14.2 μm. The measured laser power shows a quasi-saturation region with a 46% increase in slope efficiency after it. This quasi-saturation region is attributed to different current injection mechanisms.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)