Tapered ultra-high numerical aperture optical fiber tip for nitrogen vacancy ensembles based endoscope in a fluidic environment
| Autor: | Gopalakrishnan Balasubramanian, Sri Ranjini Arumugam, Dewen Duan, Vinaya Kumar Kavatamane, Yan-Kai Tzeng, Huan-Cheng Chang |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Optical fiber Physics and Astronomy (miscellaneous) FOS: Physical sciences Applied Physics (physics.app-ph) 02 engineering and technology engineering.material 01 natural sciences law.invention law 0103 physical sciences Fluidics 010302 applied physics Multi-mode optical fiber business.industry Diamond Physics - Applied Physics Microstructured optical fiber 021001 nanoscience & nanotechnology Numerical aperture Core (optical fiber) engineering Optoelectronics 0210 nano-technology business Refractive index |
| Zdroj: | Applied Physics Letters. 116:113701 |
| ISSN: | 1077-3118 0003-6951 |
| Popis: | Fixing a diamond containing a high density of Nitrogen-Vacancy (NV) center ensembles on the apex of a multimode optical fiber (MMF) extends the applications of NV-based endoscope sensors. Replacing the normal MMF with a tapered MMF (MMF-taper) has enhanced the fluorescence (FL) collection efficiency from the diamond and achieved a high spatial resolution NV-based endoscope. The MMF-taper's high FL collection efficiency is the direct result of multiple internal reflections in the tapered region caused by silica, which has a higher refractive index (RI) than the surrounding air. However, for applications involving fluidic environments whose RI is close to or higher than that of the silica, the MMF-taper loses its FL collection significantly. Here, to overcome this challenge, we replaced the MMF-taper with an ultra-high numerical aperture (NA) microstructured optical fiber (MOF) which is tapered and sealed its air capillaries at the tapered end. Since the end-sealed air capillaries along the tapered MOF (MOF-taper) have isolated the MOF core from the surrounding medium, the core retains its high FL collection and NV excitation efficiency in liquids regardless of their RI values. Such a versatile NV-based endoscope could potentially find broad applications in fluidic environments where many biological processes and chemical reactions occur. 4 pages, 5 figures |
| Databáze: | OpenAIRE |
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