Diffractive optical elements (DOEs) are key components in the miniaturization of optical systems because of their planarity and extreme thinness. We demonstrate the fabrication of DOEs by use of gray-scale photolithography with a high-energy-beam sensitive glass photomask. We obtained DOE lenses with continuous phase profiles as small as 800 μm in diameter and 5.9 μm in the outermost grating pitch by selecting a suitable optical density for each height level and optimizing the process variables. Microlenses patterned with eight levels and replicated by UV embossing with the polymer master mold showed a diffraction efficiency of 81.5%, which was sufficiently high for the devices to be used as optical pickups. The effects of deviations in diffraction efficiency between the DOE height and profile design were analyzed.
© 2005 Optical Society of America
(050.1970) Diffraction and gratings : Diffractive optics
(220.0220) Optical design and fabrication : Optical design and fabrication
(220.4610) Optical design and fabrication : Optical fabrication
Jin-Seung Sohn, Myung-Bok Lee, Wan-Chin Kim, Eun-Hyung Cho, Tae-Wan Kim, Chan-Young Yoon, No-Cheol Park, and Young-Pil Park, "Design and fabrication of diffractive optical elements by use of gray-scale photolithography," Appl. Opt. 44, 506-511 (2005)