High-Q photonic crystal slab nanocavity with an asymmetric nanohole in the center for QED

We present a new approach which allows one to insert a silica nanosphere with a single quantum dot into a highQ photonic crystal slab nanocavity with an asymmetric nanohole in the center. The high Q cavity is optimized by adjusting air holes around the L3-type cavity based on three-dimensional finite-difference time-domain simulation. High Q value of 48 700 in this asymmetric cavity is achieved. The performance of the cavity with an assumed silica sphere containing a single quantum dot in the nanohole is also discussed, in which the Q factor can reach 5 × 104 and modal volume V is 0:048 μm3 (∼0:62 ðλ0=nÞ). It is found that the electric field intensity in the nanohole is much stronger than the maximum electric field in the cavity without a nanohole. This makes it possible to locate the precise position of the quantum dot with respect to the cavity mode electric maximum. This system provides a good candidate for realizing a strong interaction between a quantumdot and cavity for the study of cavity quantum electrodynamics. © 2011 Optical Society of America OCIS codes: 230.5298, 140.3948, 270.5580.