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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 15 — Jul. 16, 2012
  • pp: 16677–16683

Emission pattern control and polarized light emission through patterned graded-refractive-index coatings on GaInN light-emitting diodes

Ming Ma, Ahmed N. Noemaun, Jaehee Cho, E. Fred Schubert, Gi Bum Kim, and Cheolsoo Sone  »View Author Affiliations

Optics Express, Vol. 20, Issue 15, pp. 16677-16683 (2012)

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Patterned graded-refractive-index (GRIN) coatings that offer the controllability of far-field emission pattern and polarization properties of GaInN light-emitting diodes (LEDs) are investigated. Compared with a planar reference LED, the light-output power of an LED with patterned GRIN coatings (GRIN LED) is enhanced by about 69%. Furthermore, the GRIN LED has bidirectional emission peaks at about 45° off-surface-normal and polarized light emission with the maximum polarization ratio occurring at the same angle, i.e. the intensity maximum and the polarization-ratio maximum coincide. The large off-surface-normal emission of the GRIN LED results from the strong light extraction through the sidewalls of the GRIN pillars, which is in good agreement with results predicted from ray-tracing simulations.

© 2012 OSA

OCIS Codes
(230.3670) Optical devices : Light-emitting diodes
(310.4165) Thin films : Multilayer design

ToC Category:
Optical Devices

Original Manuscript: April 3, 2012
Revised Manuscript: May 30, 2012
Manuscript Accepted: June 12, 2012
Published: July 9, 2012

Ming Ma, Ahmed N. Noemaun, Jaehee Cho, E. Fred Schubert, Gi Bum Kim, and Cheolsoo Sone, "Emission pattern control and polarized light emission through patterned graded-refractive-index coatings on GaInN light-emitting diodes," Opt. Express 20, 16677-16683 (2012)

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