5.5 W near-diffraction-limited power from resonant leaky-wave coupled phase-locked arrays of quantum cascade lasers

J. D. Kirch, C. C. Chang, C. Boyle, L. J. Mawst, D. Lindberg, T. Earles, D. Botez*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)

Abstract

Five, 8.36 μm-emitting quantum-cascade lasers (QCLs) have been monolithically phase-locked in the in-phase array mode via resonant leaky-wave coupling. The structure is fabricated by etch and regrowth which provides large index steps (Δn = 0.10) between antiguided-array elements and interelement regions. Such high index contrast photonic-crystal (PC) lasers have more than an order of magnitude higher index contrast than PC-distributed feedback lasers previously used for coherent beam combining in QCLs. Absorption loss to metal layers inserted in the interelement regions provides a wide (∼1.0 μm) range in interelement width over which the resonant in-phase mode is strongly favored to lase. Room-temperature, in-phase-mode operation with ∼2.2 kA/cm2 threshold-current density is obtained from 105 μm-wide aperture devices. The far-field beam pattern has lobewidths 1.65× diffraction limit (D.L.) and 82% of the light in the main lobe, up to 1.8× threshold. Peak pulsed near-D.L. power of 5.5 W is obtained, with 4.5 W emitted in the main lobe. Means of how to increase the device internal efficiency are discussed.

Original languageEnglish
Article number061113
JournalApplied Physics Letters
Volume106
Issue number6
DOIs
Publication statusPublished - 2015 Feb 9
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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