Abstract

A compact focus sensor constructed with thin film components such as a reflection twin micro-Fresnel lens and a photodetector is proposed. This sensor has a folded optical path and is insensitive to wavelength shift. Theoretical analysis indicates that the optical performance of reflection Fresnel lenses can be improved in comparison with a conventional transmission micro-Fresnel lens. The reflection twin Fresnel lens was fabricated using electron-beam lithography and exhibited diffraction-limited focusing performance with high (71%) efficiency. It was demonstrated that the focus sensor had excellent spot displacement characteristics in agreement with theoretical results, and a focus error signal was detected. This focus sensor could be useful for the optical head of an optical disk system.

© 1989 Optical Society of America

Reflection micro-Fresnel lenses and their use in an integrated focus sensor

Teruhiro Shiono, Masatoshi Kitagawa, Kentaro Setsune, and Tsuneo Mitsuyu
Appl. Opt. 28(16) 3434-3442 (1989)

Planar-optic-disk pickup with diffractive micro-optics

Teruhiro Shiono and Hisahito Ogawa
Appl. Opt. 33(31) 7350-7355 (1994)

ZnS micro-Fresnel lens and its uses

Hayami Hosokawa and Tsukasa Yamashita
Appl. Opt. 29(34) 5106-5110 (1990)

Wavelength independent grating lens system

Masayuki Kato, Satoshi Maeda, Fumio Yamagishi, Hiroyuki Ikeda, and Takefumi Inagaki
Appl. Opt. 28(4) 682-686 (1989)

Rectangular-apertured micro-Fresnel lens arrays fabricated by electron-beam lithography

Teruhiro Shiono, Kentaro Setsune, Osamu Yamazaki, and Kiyotaka Wasa
Appl. Opt. 26(3) 587-591 (1987)