Induced axial and lateral color surface contributions.

Induced aberrations in general are higher-order aberrations caused by ray perturbations of lower order, picked up in the preceding optical system. Therefore, in the case of color aberrations, induced influences can already be observed at the second order. They are generated by the preexisting first-order axial and lateral color.

Second-order axial color of thin lenses in air.

In present research, the influence of higher-order aberrations on the correction of secondary axial color is under investigation. Analytical solutions have so far been restricted to special cases and simple optical systems. Common theories require the tracing of rays of different wavelengths.

Whispering gallery modes in nanosized dielectric resonators with hexagonal cross section.

The size dependence of whispering gallery modes in dielectric resonators with hexagonal cross section has been observed within the visible spectral range for cavity diameters comparable to the light wavelength. As a model system single, tapered, high aspect ratio zinc oxide nanoneedles were analyzed. They enable systematic investigations as a function of the resonator diameter down to the nanometer regime.