Hollow-Core Optical Fibers

Belardi, Walter

doi:10.3390/fib7050050

Cited by 9 publications

(3 citation statements)

References 19 publications

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“…The other extreme is represented by hollow-core antiresonant reflecting optical waveguides (ARROWs), where both light and analyte are confined to a hollow core by a sophisticated multilayer cladding. − This antiresonant approach, which is strongly used in the context of microstructured optical fibers, , results in nearly complete overlap between the central guided mode and the medium. However, it comes at the cost of poor accessibility of the core volume due to the capillary-type geometry, as complex cladding structures need to be employed for light confinement .…”

Section: Introductionmentioning

confidence: 99%

3D-Nanoprinted Antiresonant Hollow-Core Microgap Waveguide: An on-Chip Platform for Integrated Photonic Devices and Sensors

et al. 2022

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Due to their unique capabilities, hollow-core waveguides are playing an increasingly important role, especially in meeting the growing demand for integrated and low-cost photonic devices and sensors. Here, we present the antiresonant hollow-core microgap waveguide as a platform for the on-chip investigation of light-gas interaction over centimeter-long distances. The design consists of hollow-core segments separated by gaps that allow external access to the core region, while samples with lengths up to 5 cm were realized on silicon chips through 3Dnanoprinting using two-photon absorption based direct laser writing. The agreement of mathematical models, numerical simulations and experiments illustrates the importance of the antiresonance effect in that context. Our study shows the modal loss, the effect of gap size and the spectral tuning potential, with highlights including extremely broadband transmission windows (>200 nm), very high contrast resonance (>60 dB), exceptionally high structural openness factor (18%) and spectral control by nanoprinting (control over dimensions with step sizes (i.e., increments) of 60 nm). The application potential was demonstrated in the context of laser scanning absorption spectroscopy of ammonia, showing diffusion speeds comparable to bulk diffusion and a low detection limit. Due to these unique properties, application of this platform can be anticipated in a variety of spectroscopy-related fields, including bioanalytics, environmental sciences, and life sciences.

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Section: Introductionmentioning

confidence: 99%

3D-Nanoprinted Antiresonant Hollow-Core Microgap Waveguide: An on-Chip Platform for Integrated Photonic Devices and Sensors

et al. 2022

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“…Hollow-core optical fibers (HCs) have recently gained significant interest to a large scientific community [1]. Within the last six years, a novel form of hollow-core optical fiber has been developed, which consists in a simplified HC where a set of detached tubes surrounds a central air core [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Borosilicate Based Hollow-Core Optical Fibers

Belardi

Sazio

2019

Fibers

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We discuss the fabrication of hollow-core optical fibers made of borosilicate glass. We show that, despite the high attenuation of the glass relative to silica, the fiber optical losses can be of the same order of magnitude of those obtained by using ultrapure silica glass. Short lengths of the fabricated fibers, used in combination with incoherent optical sources, provide single-mode optical guidance in both near and mid-infrared spectral ranges without any additional optical components.

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“…A conceptually different approach relies on guiding the light directly inside the liquid, thus maximizing the fraction of power inside the medium of interest. Due to the lack of total internal reflection, efficient waveguiding inside water-core waveguides requires microstructured claddings to confine the light inside the core region within leaky modes. − Substantial advancement of hollow core waveguides has been achieved in recent times within the field of microstructured optical fibers. , Via effects such as photonic band gap formation, omnidirectional guidance, , or antiresonance guidance using inhibited coupling , employed in various spectral domains, , low-loss guidance in hollow core fibers up to the dB/km level has been demonstrated (e.g., 6.6, 10 dB/km). The application range of hollow core fibers spans across multiple disciplines, including pharmaceutical detection, nano-object tracking, Raman spectroscopy, − and gas sensing …”

mentioning

confidence: 99%

The Optofluidic Light Cage – On-Chip Integrated Spectroscopy Using an Antiresonance Hollow Core Waveguide

et al. 2020

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Emerging applications in spectroscopy-related bioanalytics demand for integrated devices with small geometric footprints and fast response times. While hollow core waveguides principally provide such conditions, currently used approaches include limitations such as long diffusion times, limited light−matter interaction, substantial implementation efforts, and difficult waveguide interfacing. Here, we introduce the concept of the optofluidic light cage that allows for fast and reliable integrated spectroscopy using a novel on-chip hollow core waveguide platform. The structure, implemented by 3D nanoprinting, consists of millimeterlong high-aspect-ratio strands surrounding a hollow core and includes the unique feature of open space between the strands, allowing analytes to sidewise enter the core region. Reliable, robust, and long-term stable light transmission via antiresonance guidance was observed while the light cages were immersed in an aqueous environment. The performance of the light cage related to absorption spectroscopy, refractive index sensitivity, and dye diffusion was experimentally determined, matching simulations and thus demonstrating the relevance of this approach with respect to chemistry and bioanalytics. The presented work features the optofluidic light cage as a novel on-chip sensing platform with unique properties, opening new avenues for highly integrated sensing devices with real-time responses. Application of this concept is not only limited to absorption spectroscopy but also includes Raman, photoluminescence, or fluorescence spectroscopy. Furthermore, more sophisticated applications are also conceivable in, e.g., nanoparticle tracking analysis or ultrafast nonlinear frequency conversion.

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Hollow-Core Optical Fibers

Abstract: The possibility of guiding light in air has fascinated optical scientists and engineers since the dawn of optical fiber technology [...]

Cited by 9 publications

References 19 publications

3D-Nanoprinted Antiresonant Hollow-Core Microgap Waveguide: An on-Chip Platform for Integrated Photonic Devices and Sensors

3D-Nanoprinted Antiresonant Hollow-Core Microgap Waveguide: An on-Chip Platform for Integrated Photonic Devices and Sensors

Borosilicate Based Hollow-Core Optical Fibers

The Optofluidic Light Cage – On-Chip Integrated Spectroscopy Using an Antiresonance Hollow Core Waveguide

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