Quantum cascade lasers with a heterogeneous cascade: Two-wavelength operation

Claire Gmachl, Deborah L. Sivco, James N. Baillargeon, Albert L. Hutchinson, Federico Capasso, Alfred Y. Cho

Research output: Contribution to journalArticlepeer-review

78 Scopus citations


A quantum cascade (QC) laser with a heterogeneous cascade containing two substacks previously optimized to emit at 5.2 μm and 8.0 μm wavelengths, respectively, is presented. The low-temperature performance of the two-wavelength laser is comparable to the respective homogeneous stack lasers, indicating no penalty from the heterogeneity of the cascade. Each substack is apportioned the optimum fraction of the applied bias. This demonstrates the general applicability of this scheme. In addition, an etch-stop layer inserted between the two substacks allowed fabrication of a "tap" into the cascade. The latter was used to selectively manipulate the laser threshold of one substack, turning the 8.0 μm laser on and off while the adjacent 5.2 μm QC laser was operating undisturbed.

Original languageEnglish (US)
Pages (from-to)572-574
Number of pages3
JournalApplied Physics Letters
Issue number5
StatePublished - Jul 30 2001
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)


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