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Journal ArticleDOI

Laser speckle reduction due to spatial and angular diversity introduced by fast scanning micromirror.

M. Nadeem Akram, +4 more
- 10 Jun 2010 - 
- Vol. 49, Iss: 17, pp 3297-3304
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TLDR
Experimental results show that the speckle contrast factor can be reduced down to 5% within the integration time of the detector.
Abstract
We utilize spatial and angular diversity to achieve speckle reduction in laser illumination. Both free-space and imaging geometry configurations are considered. A fast two-dimensional scanning micromirror is employed to steer the laser beam. A simple experimental setup is built to demonstrate the application of our technique in a two-dimensional laser picture projection. Experimental results show that the speckle contrast factor can be reduced down to 5% within the integration time of the detector.

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Citations
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Journal ArticleDOI

Low spatial coherence electrically pumped semiconductor laser for speckle-free full-field imaging

TL;DR: A chip-scale, electrically pumped semiconductor laser based on a novel design is presented, demonstrating high power per mode with much lower spatial coherence than conventional laser sources, which could enable a wide range of full-field imaging applications.
Journal ArticleDOI

Complex lasers with controllable coherence

TL;DR: In this paper, the authors present an overview of complex, low and tunable spatial coherence properties of laser cavity geometries with a focus on their spatial and spectral properties.
Journal ArticleDOI

Laser speckle reduction by multimode optical fiber bundle with combined temporal, spatial, and angular diversity

TL;DR: Speckle contrast close to that of white light was obtained using a vibrating fiber bundle with combined temporal, spatial, and angular diversities of the illumination.
Journal ArticleDOI

Speckle noise suppression in digital holography by angular diversity with phase-only spatial light modulator

TL;DR: The experimental results demonstrate the effectiveness, repeatability, and practicability of the proposed approach, and the greatly suppressed speckle noise which is in good agreement with the theoretical results.
Journal ArticleDOI

Speckle reduction and maintaining contrast in a LASER pico-projector using a vibrating symmetric diffuser

TL;DR: A design for a LASER pico-projector with a low speckle contrast value and high contrast ratio that maintains system efficiency is proposed and utilizes two diffusers and a Voice Coil Motor (VCM) oscillator.
References
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Journal ArticleDOI

Speckle Reduction in Laser Projection Systems by Diffractive Optical Elements

TL;DR: A new method for eliminating speckles in the far field by using a diffractive optical element is proposed, which can be reduced to a few percent while good beam quality is preserved.
Journal ArticleDOI

Speckle Removal by a Slowly Moving Diffuser Associated with a Motionless Diffuser

TL;DR: In this article, a two-diffuser system of which one diffuser is motionless, the other moving is used to destroy the spatial coherence of laser light only partially when the integration time is finite.
Proceedings ArticleDOI

Speckle contrast reduction in laser projection displays

TL;DR: In this paper, the maximum speckle contrast reduction for a given system was derived, and two novel approaches to achieve the maximum reduction were introduced, and the Hadamard diffuser was applied to the GLV TM.
Journal ArticleDOI

Speckle Reduction Using Multiple Tones of Illumination

TL;DR: A direct extension of this method to holographic microscopy, using a multitone laser, should permit one to record and reconstruct holograms of diffraction-limited resolution that are essentially speckle-free.
Journal ArticleDOI

Hadamard speckle contrast reduction

Jahja I. Trisnadi
- 01 Jan 2004 - 
TL;DR: The condition for a diffuser to produce the maximum speckle contrast reduction with the minimum number of distinct phase patterns is derived and a binary realization of this optimum diffuser is obtained by mapping the rows or columns of a Hadamard matrix to the phase patterns.
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