Effect of a nanoparticle on the optical properties of a photonic crystal cavity: theory and experiment

Single quantum emitters can be coupled to photonic crystal (PC) cavities by placing their host nanoparticles into the cavity field. We describe fabrication, characterization, and tuning of gallium-phosphide PC cavities that resonate in the visible, and simulations and measurements of the effect of a nanoparticle on the optical properties of these cavities. Simulations show that introducing a 50 nm (100 nm) sized nanoparticle into S1 and L3-type cavities, with original quality factors of 18·10^3 and 73·10^3, respectively, reduces the quality factor by <10% (?50%). Furthermore, simulations indicate that an emitter embedded in a 50 nm (100 nm) sized nanoparticle can be coupled 3.5 (9) times more effectively to an S1 cavity than to an L3 cavity. We employ a nanopositioning technique to position individual, 50 nm sized nanocrystals into S1 cavities, and find that the quality factors are reduced by a factor of 0.9±0.1 from the original values of order 10^3.