Open AccessReduction of speckle noise and mitigation of beam wander in tunable external cavity quantum cascade lasers using rotating diamond/KBr pellet coupled with multimode fiber
Author(s) -
Yohan Yoon,
Christopher J. Breshike,
Christopher A. Kendziora,
Robert Furstenberg,
R. Andrew McGill
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.008011
Subject(s) - optics , multi mode optical fiber , speckle pattern , materials science , diamond , cascade , quantum cascade laser , speckle noise , beam (structure) , laser , diffuser (optics) , noise (video) , noise reduction , optoelectronics , optical fiber , physics , chemistry , light source , image (mathematics) , chromatography , artificial intelligence , computer science , composite material , acoustics
We experimentally demonstrate speckle noise reduction and beam wander mitigation by using a rotating diamond/KBr pellet and a multimode fiber (MMF). As the diamond/KBr diffuser is rotated, the reflected speckle images that are captured by an infrared camera are temporally averaged. We demonstrate 78% speckle noise reduction by averaging 25 frames, which is within 80% of the theoretical contrast reduction. Large beam position fluctuations are also significantly suppressed by adding the MMF. This combination of beam wander mitigation and speckle reduction offers significant benefits for emerging optical technologies that use quantum cascade lasers as illumination sources.