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9 results on '"Naveen Gajendra"'

1. Miniature 120-beam coherent combiner with 3D printed optics for multicore fiber based endoscopy

Author

Sivankutty, Siddharth, Bertoncini, Andrea, Tsvirkun, Victor, Kumar, Naveen Gajendra, Brévalle, Gaelle, Bouwmans, Géraud, Andresen, Esben Ravn, Liberale, Carlo, and Rigneault, Hervé

Subjects
Physics - Optics, Physics - Applied Physics
Abstract

We report high efficiency, miniaturized, ultra-fast coherent beam combining with 3D printed micro-optics directly on the tip of a multicore fiber bundle. The highly compact device foot-print (180 micron diameter) facilitates its incorporation into a minimally invasive ultra-thin nonlinear endoscope to perform two-photon imaging, Comment: Published in Optics Letters

Published
2022
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3. A Hollow-Core Fiber Based Stand-Alone Multimodal (2-Photon, 3-Photon, SHG, THG) Nonlinear Flexible Imaging Endoscope System

Author

Septier, Dylan, Brevalle-Wasilewski, Gaelle, Lefebvre, Eloise, Kumar, Naveen Gajendra, Wang, Yong Jian, Kaszas, Attila, Rigneault, Herve, and Kudlinski, Alexandre

Abstract

Multimodal nonlinear endoscopes have been a topic of intense research over the past two decades, enabling sub-cellular and label-free imaging in areas not reachable with table-top microscopes. They are sophisticated systems that can be implemented on an optical table in a lab environment, but they cannot be easily moved within or out of the lab. We present here a multimodal and flexible nonlinear endoscope system able to perform two-photon excited fluorescence and second harmonic generation imaging with a stand-alone and movable kart integrating a compact ultrashort laser source. In addition, the system can perform three-photon excited fluorescence and third harmonic generation imaging thanks to a delivery optical fiber that connects a large frame laser system to the stand-alone kart. The endoscopic fiber probes and delivery optical fibers are based on functionalized negative curvature hollow core fibers. The endoscope distal head has a diameter $< $2.2 mm and can perform nonlinear imaging at max 10 frames/s over a field of view up to 600 μm with a $\sim$1 μm spatial resolution.

Published
2024
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5. Coupling optimized bending-insensitive multi-core fibers for lensless endoscopy

Author

Naveen Gajendra Kumar, Siddharth Sivankutty, Victor Tsvirkun, Andy Cassez, Damien Labat, Rosa Cossart, Geraud Bouwmans, Esben Ravn Andresen, Hervé Rigneault, Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), MOSAIC (MOSAIC), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut de Neurobiologie de la Méditerranée [Aix-Marseille Université] (INMED - INSERM U1249), and Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Atomic and Molecular Physics, and Optics
Abstract

International audience; We report a bending-insensitive multi-core fiber (MCF) for lensless endoscopy imaging with modified fiber geometry that enables optimal light coupling in and out of the individual cores. In a previously reported bending insensitive MCF (twisted MCF), the cores are twisted along the length of the MCF allowing for the development of flexible thin imaging endoscopes with potential applications in dynamic and freely moving experiments. However, for such twisted MCFs the cores are seen to have an optimum coupling angle which is proportional to their radial distance from the center of the MCF. This brings coupling complexity and potentially degrades the endoscope imaging capabilities. In this study, we demonstrate that by introducing a small section (1 cm) at two ends of the MCF, where all the cores are straight and parallel to the optical axis one can rectify the above coupling and output light issues of the twisted MCF, enabling the development of bend-insensitive lensless endoscopes.

Published
2023

6. Miniature 120-beam coherent combiner with 3D printed optics for multicore fiber based endoscopy

Author

Gaelle Brévalle, Siddharth Sivankutty, Géraud Bouwmans, Naveen Gajendra Kumar, Hervé Rigneault, Andrea Bertoncini, Esben Ravn Andresen, Carlo Liberale, Victor Tsvirkun, Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), MOSAIC (MOSAIC), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), King Abdullah University of Science and Technology (KAUST), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), ANR-20-CE19-0028,NAIMA,Imagerie rapide et non invasive par fibre optique multi-modes(2020), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), and Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)

Subjects
Optics and Photonics, 3d printed, Materials science, Physics::Optics, FOS: Physical sciences, 02 engineering and technology, Applied Physics (physics.app-ph), Multicore fiber, 01 natural sciences, Endoscopy, Gastrointestinal, 010309 optics, Footprint (electronics), Optics, Optical imaging, 0103 physical sciences, medicine, Fiber bundle, ComputingMilieux_MISCELLANEOUS, Endoscopes, Photons, medicine.diagnostic_test, business.industry, Endoscopy, Physics - Applied Physics, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, Bundle, Printing, Three-Dimensional, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, 0210 nano-technology, business, Beam (structure), Physics - Optics, Optics (physics.optics)
Abstract

We report high efficiency, miniaturized, ultra-fast coherent beam combining with 3D printed micro-optics directly on the tip of a multicore fiber bundle. The highly compact device foot-print (180 micron diameter) facilitates its incorporation into a minimally invasive ultra-thin nonlinear endoscope to perform two-photon imaging, Comment: Published in Optics Letters

Published
2022
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7. Tapered multi-core fiber for biomedical lens-less endoscopes

Author

El Moussawi, Fatima, primary, Hofer, Matthias, additional, Kumar, Naveen Gajendra, additional, Cassez, Andy, additional, Labat, Damien, additional, Bouwmans, Géraud, additional, Vanvincq, Olivier, additional, Rigneault, Hervé, additional, and Andresen, Esben Ravn, additional

Published
2022
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8. Flexible lensless endoscopes for 2-photon fluorescence imaging of hippocampal neurons in mice

Author

Naveen Gajendra Kumar, Esben Ravn Andresen, Rosa Cossart, Géraud Bouwmans, Hervé RIGNEAULT, Institut FRESNEL (FRESNEL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), MOSAIC (MOSAIC), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Composants logiciels et matériels pour l'Information et la Communication Avancé - USR 3380 (IRCICA), Institut de Neurobiologie de la Méditerranée [Aix-Marseille Université] (INMED - INSERM U1249), Institut National de la Santé et de la Recherche Médicale (INSERM)-Aix Marseille Université (AMU), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2021

9. Lensless endoscopy

Author

Naveen Gajendra, Siddharth Sivankutty, Viktor Tsvirkun, Esben Ravn Andresen, Olivier Vanvincq, Géraud Bouwmans, Hervé RIGNEAULT, Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), MOSAIC (MOSAIC), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), and Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)

Subjects
[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2021

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