Manipulation of the spontaneous emission dynamics of quantum dots in two-dimensional photonic crystals

We demonstrate the ability to control the spontaneous emission dynamics of self-assembled quantum dots via the local density of optical modes in two-dimensional (2D) photonic crystals. We show that an incomplete 2D photonic band gap is sufficient to significantly lengthen the spontaneous emission lifetime (>2×) over a wide bandwidth (Δλ⩾40nm) . For dots that are both spectrally and spatially coupled to strongly localized [V_modes∼1.5(λ/n)³] , high Qtilde 2700 optical modes, we have directly measured a strong Purcell-enhanced shortening of the emission lifetime ⩾5.6× , limited only by our temporal resolution. Analysis of the spectral dependence of the recombination dynamics shows a maximum lifetime shortening of 19±4 . From the directly measured enhancement and suppression we show that the single-mode coupling efficiency for quantum dots in such structures is at least β=92% and is estimated to be as large as ∼97% .