[OPTICAL REVIEW Vol. 8, No. 4 (2001) 245-248]

Wavelength-Multiplexing Diffractive Phase Element with Quantized Phase Structure

Yusuke OGURA1,*, Nobuhiro SHIRAI1, Jun TANIDA1 and Yoshiki ICHIOKA2

1Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka, 565-0871 Japan, 2Nara National College of Technology, 22, Yata-cho, Yamatokoriyama, Nara, 639-1080 Japan

(Received February 1, 2001; Accepted April 26, 2001)

We have reported on the design algorithm of the wavelength-multiplexing diffractive phase element (WMDPE) capable of generating independent spot patterns for more than two wavelengths. [J. Opt. Soc. Am. A 18 (2001) 1082] In this paper, the stepwise quantization method proposed by F. Wyrowski [J. Opt. Soc. Am. A 7 (1990) 961] is built into the algorithm to design the WMDPE with quantized phase structure. Validity of the method is verified by the WMDPE for 7 wavelengths with 9 phase levels. The optical experiment demonstrates that the fabricated WMDPE generates correct patterns for different wavelengths. Performance dependence of the WMDPE on the number of quantized phase levels is discussed based on the simulation results.

Key words : wavelength multiplexing, diffractive phase element, stepwise quantization method, spot pattern, quantized phase structure