Spectral and directional properties of elliptical quantum-dot microlasers

Qingji Zeng, Evan Lafalce, Chun Hao Lin, Marcus J. Smith, Sidney T. Malak, Jaehan Jung, Young Jun Yoon, Zhiqun Lin, Vladimir V. Tsukruk, Zeev Valy Vardeny

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We have fabricated microdisk lasers of colloidal quantum dots in circular and elliptical forms with different aspect ratios. By characterizing the laser emission spectrum under optical pumping and through mode simulation calculations, we demonstrate that the elliptical resonators can display two sets of whispering-gallery modes that interact to varying degrees depending on the aspect ratio. This causes significant mode splitting in the emission spectra when the mode interaction is at maximum. We also performed angular-dependent laser emission measurements for characterizing the emission pattern of the microlasers. We found that the emission pattern becomes less isotropic and more directional as the boundary deviates further from circular symmetry. In addition, we demonstrate that the emission directional properties of these microlasers can be further tailored by coupling pairs of elliptical microcavities together in different manners, where the long or short elliptical axis interacts most strongly.

Original languageEnglish
Article number032218
JournalJournal of Photonics for Energy
Issue number3
StatePublished - 1 Jul 2018

Bibliographical note

Publisher Copyright:
© 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).


  • lasers
  • microcavities
  • optics
  • photonics
  • quantum dots


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