title: Speckle reduction using a motionless diffractive optical element.
abstract: Speckle reduction by moving diffuser has been previously studied in display systems with coherent light sources, such as lasers. In this Letter, we propose a motionless diffractive optical element (DOE) for speckle reduction. The DOE was designed based on finite-element method simulations, fabricated using micromachining technology, and characterized for despeckle efficiency. Experiments using a DOE with two gratings have indicated that the speckle was suppressed to 50%, which shows fair agreement with theoretical analysis. With some modification of this DOE, the speckle noise can be reduced to 10% according to the theory.
authors.affiliation: Faculty of Science and Engineering, Vestfold University College, N-3103 Tonsberg, Norway.
authors.forename: Guangmin
authors.initials: G
authors.lastname: Ouyang
authors.forename: Zhaomin
authors.initials: Z
authors.lastname: Tong
authors.forename: M Nadeem
authors.initials: MN
authors.lastname: Akram
authors.forename: Kaiying
authors.initials: K
authors.lastname: Wang
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kartashov
authors.forename: Xin
authors.initials: X
authors.lastname: Yan
authors.forename: Xuyuan
authors.initials: X
authors.lastname: Chen