Nanoemitters in a defect layer embedded in photonic crystals: synthesis and optical characterization
Résumé
Manipulation of the emission of nanocrystals embedded in photonic crystals can pro-vide single photon source for quantum information.Artificial opals are 3D photonic crystals whose synthesis is based on self-assembly of dielectricspheres. This cost-efficient and versatile method does not require a high technological platform andleads to nanostructured samples over cm range. In order to obtain light confinement inside opals,several fabrication methods have been used to create a defect. Artificial opals with a planar defectcan be considered as a good ”model system” to study the modification of the optical properties ofnanoemitters in a photonic crystal.We will present two efficient and reliable methods to engineer a defect between two silica opals:by sputtering a controlled amount of silica or by the transfer of a monolayer of silica spheres ofdifferent diameter by the Langmuir-Blodgett or Schaefer technique. The optical properties of theprepared samples were characterized by transmission and specular reflection spectra. Tunable andhighly transmitted and reflected optical modes were evidenced, in good agreement with FiniteDifference Time Domain simulations (FDTD).Colloidal II-VI nanocrystals are efficient and stable emitters which can emit single photons. Thesenanoemitters were introduced in the defect. The collected fluorescence of these nanocrystalspresents an emission diagram which is modified by the photonic crystal and especially by thedefect layer.