Investigation of integrated diffractive/refractive microlens microfabricated by focused ion beam

Integrated diffractive/refractive microlens with dual focus point is introd uced in detail in the view of design, microfabrication, and testing. Two ma nufacturing methods-milling and deposition directly by focused ion beam tec hnology is discussed and compared. It was shown by testing results that the deposition method is more suitable to form the refractive spherical/aspher ical lens and milling is suitable for microfabrication of diffractive optic al elements. Focusing spot size (full width at half maximum) are 0.55 and 0 .87 mu m (lambda = 638 nm) for refractive and diffractive lens, respectivel y, with NA 0.35 and 0.5. (C) 2000 American Institute of Physics. [S0034-674 8(00)01006-6].