Photonic molecules defined by SU-8 photoresist strips on a photonic crystal waveguide.

We present experimental and numerical investigations of photonic molecules obtained from laser patterned SU-8 photoresist strips on photonic crystal waveguides. Properties of cavities defined by a single strip are investigated and we show that two adjacent strips on a waveguide form a pair of optically coupled cavities. Simulation results and micro-photoluminescence mapping measurements demonstrate that the coupling strength is tunable by controlling the separation between the strips. Confocal mapping with decoupled collection and excitation points is used to explicitly show coupling between two cavities of a photonic molecule.

Optical fabrication and characterisation of SU-8 disk photonic waveguide heterostructure cavities.

In order to demonstrate cavity quantum electrodynamics using photonic crystal (PhC) cavities fabricated around self-assembled quantum dots (QDs), reliable spectral and spatial overlap between the cavity mode and the quantum dot is required. We present a method for using photoresist to optically fabricate heterostructure cavities in a PhC waveguide with a combined photolithography and micro-photoluminescence spectroscopy system. The system can identify single QDs with a spatial precision of ±25 nm, and we confirm the creation of high quality factor cavity modes deterministically placed with the same spatial precision. This method offers a promising route towards bright, on-chip single photon sources for quantum information applications.