Reduction of Speckle Noise and Mitigation of Beam Wander in Tunable External Cavity Quantum Cascade Lasers Using Rotating Diamond/KBr Pellet Coupled with Multimode Fiber
Journal Article - Open Access
NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States
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We experimentally demonstrate speckle noise reduction and beam wander mitigation by using a rotating diamondKBr pellet and a multimode fiber MMF. As the diamondKBr 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. C 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.
- Lasers and Masers