[OPTICAL REVIEW Vol. 19, No. 2 (2012) 50-57]
© 2012 The Japan Society of Applied Physics

Computer-Generated Hologram Fabricated by Electron-Beam Lithography for Noise Reduction

Hitoshi TAMURA1,2* and Yukihiro ISHII1

1Department of Applied Physics, Tokyo University of Science, Shinjuku, Tokyo 162-8601, Japan 2Department of Electronics, University of Industrial Technology, Sagamihara 252-5196, Japan

(Received November 13, 2010; Accepted November 17, 2010)

A Lohmann-type computer-generated hologram (CGH) is fabricated using an electron-beam lithographic system. A high-resolution groove width of 0.2 μm is attained in relief gratings by changing the e-beam exposures. A diffraction efficiency close to ∼30.4% is obtained by using resist-on-silicon recording materials and cell-structural apertures in a CGH. The reconstructed images exhibit fewer phase noises owing to the incorporation of a non-overflow cell structure into a CGH. The CGH is designed for reconstruction-noise reduction by using an iterative error-reduction algorithm. The designed CGH exhibits fewer reconstruction noises such that the performance function in the convergence is smaller by a factor of 1/3 than that in the first iteration. Experiments demonstrating the performance of CGHs obtained by electron-beam lithography are presented.

Key words: computer-generated hologram, Lohmann-type cell orientation, electron-beam lithography, error-reduction algorithm, noise reduction in reconstruction

*E-mail address: tamura@uitec.ac.jp