High quality beaming and efficient free-space coupling in L3 photonic crystal active nanocavities

Opt Express. 2012 Aug 13;20(17):18876-86. doi: 10.1364/OE.20.018876.

Abstract

We report on far-field measurements of L3 photonic crystal (PhC) cavities with high quality beaming. This is achieved by means of the so-called "band folding" technique, in which a modulation of the radius of specific holes surrounding the cavity is introduced. Far-field patterns are measured from photoluminescence of quantum wells embedded in the PhC. A very good agreement between experimental results and simulated radiation patterns has been found. Laser effect is demonstrated in the beaming cavity with a threshold comparable to the regular one. In addition, free-space input coupling to this cavity has been achieved. In order to fully analyze the coupling efficiency, we generalize the approach developed in S. Fan, et al., [J. Opt. Soc. Am. A 20, 569 (2003)], relaxing the hypothesis of mirror symmetry. The obtained coupling efficiencies are about 15% with quality factors (Q) exceeding 10(4). These results further validate the "folding" technique on L3 cavities for nanocavity realization with efficient free-space coupling and high Q factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Computer-Aided Design
  • Crystallization
  • Equipment Design
  • Equipment Failure Analysis
  • Light
  • Nanostructures / chemistry*
  • Nanotechnology / instrumentation*
  • Scattering, Radiation
  • Surface Plasmon Resonance / instrumentation*
  • Transducers*