Cascaded-transition Quantum Cascade laser

Jingyuan Linda Zhang, Xue Huang, Claire F. Gmachl, Vadim Tokranov, Serge Oktyabrsky

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The Quantum Cascade (QC) laser is a semiconductor laser based on intersubband transitions in the conduction band of a multiple quantum-well heterostructure, and is a highperformance light source in the mid-infrared and terahertz region. With the aim of improving the quantum efficiency and power efficiency of long-wavelength QC lasers, based on the principle of conventional single-transition QC lasers, we demonstrate a cascaded-transition, long-wavelength (λ ∼ 14.6 μm) QC laser where an electron makes two consecutive, cascading optical transitions and emits two energy-matched photons in each active region. The laser structure grown consists of a cascaded-transition active core with 25 stages sandwiched between two conventional single-transition active cores with 30 stages each. From the grown samples, laser emission from ∼ 680 cm-1 to ∼ 700 cm -1 (λ ∼ 14.7-14.3 μm) with threshold current density of 4.8 kA/cm2 at 80 K is observed. The laser functions in pulsed mode up to ∼ 240 K, with a characteristic temperature of 190-230 K for ridge widths around 20 μm. From the current-voltage (I-V) measurement, two turn-on's, defined as the electric field at which the subbands line up to create a low-resistive state, are observed, which is consistent with the I-V of a cascaded-transition only mesa, which, in turn, is suggestive of the functionality of the cascaded-transition active core; each turn-on relates to electron transport through the upper laser subbands and the middle subband respectively.

Original languageEnglish (US)
Title of host publication2012 Lester Eastman Conference on High Performance Devices, LEC 2012
StatePublished - Dec 1 2012
Event2012 Lester Eastman Conference on High Performance Devices, LEC 2012 - Providence, RI, United States
Duration: Aug 7 2012Aug 9 2012

Publication series

Name2012 Lester Eastman Conference on High Performance Devices, LEC 2012


Other2012 Lester Eastman Conference on High Performance Devices, LEC 2012
Country/TerritoryUnited States
CityProvidence, RI

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


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