Diffraction from a point light source (a laser diode) was studied. The diffraction images were found to be magnified without using a lens and to move corresponding to the displacement of the slit aperture. A digital encoder using this diffraction is proposed to obtain very high resolution without a lens.
© 1988 Optical Society of America
Jun Akedo, Haruhiko Machida, Hiroshi Kobayashi, Yoshikatsu Shirai, and Hideaki Ema, "Point source diffraction and its use in an encoder," Appl. Opt. 27, 4777-4781 (1988)