Improved control over the interaction between light and matter has been a driving force of technology since the invention of the laser in the 1960s. The strongest interactions (and most interesting physics) are observed when both photons and electrons are confined to small physical volumes. By placing photonic nanomaterials into optical microcavities we can modify the 'internal' electronic properties of the materials and observe changes in their behaviour which can be exploited for a wide range of applications from IT to healthcare and security.
Fig.1 Schematic of an 'open access' optical cavity.
A recent highlight of our research is the development of tunable 'open access' microcavities with femtolitre (10-15 litre) mode volumes and quality factors of order 104. These microcavities allow precise control of the alignment to a nano-object for detailed study of the changing properties. By fabricating large arrays of the microcavities we also aim to develop high throughput sensing techniques for the chemical and biological sciences.
Fig 2: (left and middle) optical transmission spectra for our tunable microcavities, and (right) large arrays of microcavity structures, each of 8 micrometres diameter.