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We demonstrate the nonresonant magnetic interaction at optical frequencies between a photonic crystal microcavity and a metallized near-field microscopy probe. This interaction can be used to map and control the magnetic component of the microcavity modes. The metal coated tip acts as a microscopic conductive ring, which induces a magnetic response opposite to the inducing magnetic field. The resulting shift in resonance frequency can be used to measure the distribution of the magnetic field intensity of the photonic structure and fine-tune its optical response via the magnetic field components.

We report on the achievement of simultaneous quantum degeneracy in a mixed gas of fermionic 40K and bosonic 87Rb. Potassium is cooled to 0.3 times the Fermi temperature by means of an efficient thermalization with evaporatively cooled rubidium. Direct measurement of the collisional cross-section confirms a large interspecies attraction. This interaction is shown to affect the expansion of the Bose-Einstein condensate released from the magnetic trap, where it is immersed in the Fermi sea.