Near-field Optical Spectroscopy on Photonic Metamaterials

Most photonic metamaterials consist of basic buildingblocks which are specifically engineered to exhibitelectromagnetic resonances. These determine theoptical properties of the material, thus renderingpossible novel optical properties, such as magneticresponses at optical frequencies, negativepermittivities and permeabilities, and even negativerefractive indices. With these characteristicsmetamaterials expanded the range of what can berealised in optics, stimulating a vibrant andfast-growing field of fundamental research. In thiswork, the field distributions of resonant modes inselected 2-D metamaterials are investigatedexperimentally as well as numerically. Spectroscopicexperiments are carried out with scanning near-fieldoptical microscopes with aperture probes incollection mode. For the complementing numericalstudies a theoretical model of the transmissionprocess through the near-field aperture probes isintroduced. This model is discussed and data derivedwith the model are used to corroborate theexperimental results.