Electron-beam-written reflection diffractive microlenses for oblique incidence

Reflection microlenses for oblique incidence can be flexibly used without a beam splitter, and also could be key devices in planar optics and optical interconnections with a zigzag optical path within the substrate. The functions of the electron-beam writing system that we developed have been expanded so that the diffraction-limited microlenses for oblique incidence can be fabricated. It is demonstrated that electron-beam written microlenses including rectangular- apertured lens array exhibit the diffraction-limited focusing characteristics with 78% high efficiency at a large oblique angle of 30 degree(s).