Abstract

Electron-beam (EB) lithography has several advantages for the fabrication of micro-optic diffractive components, because submicron patterns and blazed relief structure can be formed. We developed the computer-controlled EB writing system¹ suitable for the fabrication of diffractive optics. Figure 1 shows the block diagram of the system. Specially designed pattern generators are included to reduce the amount of writing data and to make possible high-speed writing. By using the system, we fabricated various types of blazed diffractive microlenses and their arrays including rectangular-apertured lenses and elliptical lenses. These lenses exhibited¹ the diffraction-limited focusing performance with a high efficiency of greater than 70%. In particular, reflection diffractive microlenses found to be promising, because the fabrication accuracy and the optical characteristics can be greatly improved compared with the transmission diffractive microlenses. In addition, reflection diffractive microlenses for oblique incidence can be flexibility used without 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°.

© 1995 IEEE