Abstract
The images on a dot-matrix hologram contain many two-dimensional (2D) dots with different grating orientations and different grating pitches. Because the zeroth-order light nondiffracted by different grating structures has the same progress direction, the nondiffracted light can be diffracted to a 2D spot spectrum by the 2D dot structure. The 2D spot spectrum depends on grating depths and dot sizes. Although ordinary noises are troublesome for 2D spots, noises caused by special dot arrangement defects or special grating moiré fringes are useful in checking holograms. Since the features of grating depths, dot sizes, dot arrangement defects, and grating moiré fringes can be randomly changed on a case by case basis, 2D spot spectra in different cases are different. The aforementioned random features are used to identify dot-matrix holograms.
© 2006 Optical Society of America
Full Article | PDF ArticleMore Like This
Chih-Kung Lee, Jeremy Wen-Jong Wu, Sheng-Lie Yeh, Chih-Wen Tu, Yi-An Han, Eric Hong-Zong Liao, Linus Ying-Yueh Chang, I-En Tsai, Hsiu-Hung Lin, Jeffrey Chi-Tang Hsieh, and Julie Tsai-Wei Lee
Appl. Opt. 39(1) 40-53 (2000)
Marek Skeren, Pavel Fiala, and Ivan Richter
Appl. Opt. 45(1) 27-32 (2006)
Sheng Lih Yeh, Kuang Tsan Lin, and Yu Jui Cheng
Appl. Opt. 46(17) 3455-3461 (2007)