Second harmonic generation in quantum cascade lasers pumped by femtosecond mid-infrared pulses

Sheng Liu, Hong Cai, Elaine Lalanne, Peter Q. Liu, Xiaojun Wang, Claire F. Gmachl, Anthony M. Johnson

Research output: Contribution to journalArticle

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Abstract

Second harmonic generation (SHG) pulses at ∼ 2.25 m have been obtained from a 4.5 m quantum cascade laser (QCL) when it is resonantly pumped by transverse magnetic polarized 120 fs, 4.5 m pulses through the QCL's front facet at room temperature. The measured SHG spectrum narrows when the bias across the QCL increases due to the electron population re-distribution and subband realignment. The expected quadratic dependence of the SHG with pump power is observed but saturates at higher pump powers. The linear to nonlinear power conversion efficiency is calculated (∼2 W/W2) and compared with theoretical calculation. This experiment provides an alternative way of investigating the carrier dynamics in QCLs.

Original languageEnglish (US)
Article number122104
JournalApplied Physics Letters
Volume99
Issue number12
DOIs
StatePublished - Sep 19 2011

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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