Abstract

Electron-beam lithography has several advantages for the fabrication of diffractive optical components, because submicrometer patterns and blazed relief structures can be formed. We developed the computer-controlled electron-beam writing system for diffractive optics. By using the system, we fabricated various types of blazed diffractive microlenses, including rectangular-apertured lenses and elliptical lenses. These lenses exhibited the diffraction-limited focusing performance with a high efficiency of greater than 70%. In particular, reflection diffractive microlenses were found to be very promising, because their fabrication accuracy and the optical characteristics can be greatly improved over those of transmission diffractive microlenses. In addition, reflection diffractive microlenses for oblique incidence can be flexibly used without a beam splitter and are key devices in planar optics. It is demonstrated that these lenses showed the diffraction-limited focusing performance at a large oblique angle of 30°.

© 1992 Optical Society of America