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 $(>2\times )$ over a wide bandwidth $(\Delta \lambda ⩾40\mathrm{nm})$. For dots that are both spectrally and spatially coupled to strongly localized $[V_{\mathit{\text{modes}}}\sim 1.5{(\lambda ∕n)}^3]$, high $Q\sim 2700$ optical modes, we have directly measured a strong Purcell-enhanced shortening of the emission lifetime $⩾5.6\times$, limited only by our temporal resolution. Analysis of the spectral dependence of the recombination dynamics shows a maximum lifetime shortening of $19\pm 4$. From the directly measured enhancement and suppression we show that the single-mode coupling efficiency for quantum dots in such structures is at least $\beta =92\%$ and is estimated to be as large as $\sim 97\%$.