High-efficiency blazed diffractive optical elements for the violet wavelength fabricated by electron-beam lithography
Blazed diffractive optical elements (DOEs) were studied for the violet wavelength by electron-beam lithography. By optimizing electron-beam writing parameters and electron-dose distributions, we fabricated eight kinds of grating (period Lambda = 10-0.54 mum) with excellent blazed structure. It has been demonstrated that the measured diffraction efficiency values agreed well with the rigorous theoretical ones. For the fine period of 0.54 mum, we confirmed a peak appearance of 75.6% (TE) experimentally. A wave aberration as small as approx]0.01[lambda (rms) was obtained for the first-order diffracted wave from the fabricated DOEs, Blazed DOEs for the violet wavelength could be used as key devices in a high-density optical disk pickup of the next generation.