Manipulation of the Spontaneous Emission Dynamics of Quantum Dots in 2D Photonic Crystals

We demonstrate the ability to control the spontaneous emission dynamics of self-assembled quantum dots by tuning the local density of optical modes using 2D photonic crystals. We shown that a 2D TE-polarised photonic bandgap is sufficient to significantly lengthen the spontaneous emission lifetime ($\geq2\times$) over a wide bandwidth ($\Delta\lambda\geq50$ nm). For dots that are both \textit{spectrally} and \textit{spatially} coupled to strongly localised ($V_{mode}\leq1.5(\lambda/n)^{3}$), high $Q\geq2700$ optical modes, we observe a very strong Purcell enhancement of the emission rate ($\geq6\times$). Analysis of the spectral dependence of the recombination dynamics shows that the maximum lifetime shortening is $\geq20$, close to the limit required strong light-matter coupling. From the measured enhancement and suppression we show that the single mode coupling efficiency for ideal quantum dots in such structures is $\beta\sim98%$.