Microlens arrays by field-assisted Ag(+)-exchange

The formation of both cylindrical as well as sperical microlens arrays by field assisted Ag+-exchange with N.A. up to 0.2 is presented. A special designed optical glass enabling a refractive index increase of 0.14 is used. Modelling of field assisted exchange processes and the aquisition of material parameters like concentration dependent diffusion coefficient are discussed. The lenses are characterized by a shearing interferometer and exhibit diffraction limited performance with numerical apertures N.A. up to 0.20.