Nanostructured Optical Fiber Research Articles

Lifetime of Violet 1 Dye Doping the Polymer Nanostructured Optical Fibers and Thin Films for Biomedical applications

This study, the homemade electrospinning system was used to produces the [PMMA] polymer nanofibers doped with Violet 1 dye and also prepared polymer films. The fluorescence spectra showed the intensity of emission increase with concentration, the lifetime measured by using single-photon counting technique showed the lifetime increased with concentration increased until the concentration reach (0.5 *10−3)[M] then it drops exponentially to reaches to (2 nsec). Also, lifetime measured in low temperature. This study showed in low concentration, the self-absorption dominated, whereas at high concentration the internal quenching dominated.

Nanostructured sapphire optical fiber embedded with Au nanorods for high-temperature plasmonics in harsh environments.

Sensors for harsh environments must exhibit robust sensing response and considerable thermal and chemical stability. We report the exploration of a novel all-alumina nanostructured sapphire optical fiber (NSOF) embedded with Au nanorods (Au NRs) for plasmonics-based sensing at high temperatures. Temperature dependence of the localized surface plasmon resonance (LSPR) of Au NRs was studied in conjunction with numerical calculations using the Drude model. It was found that LSPR of Au NRs changes markedly with temperature, red shifting and increasing in transmission amplitude as the temperature increases. Furthermore, this variation is highly localized through tunneling by overlapping the near-field of thin cladding and sapphire optical fiber. The NSOF embedded with Au NRs has the potential for sensing in advanced energy generation systems.

Recent advances in nano-photonic techniques for pharmaceutical drug monitoring with emphasis on Raman spectroscopy

Abstract Innovations in Raman spectroscopic techniques provide a potential solution to current problems in pharmaceutical drug monitoring. This review aims to summarize the recent advances in the field. The developments of novel plasmonic nanoparticles continuously push the limits of Raman spectroscopic detection. In surface-enhanced Raman spectroscopy (SERS), these particles are used for the strong local enhancement of Raman signals from pharmaceutical drugs. SERS is increasingly applied for forensic trace detection and for therapeutic drug monitoring. In combination with spatially offset Raman spectroscopy, further application fields could be addressed, e.g. in situ pharmaceutical quality testing through the packaging. Raman optical activity, which enables the thorough analysis of specific chiral properties of drugs, can also be combined with SERS for signal enhancement. Besides SERS, micro- and nano-structured optical hollow fibers enable a versatile approach for Raman signal enhancement of pharmaceuticals. Within the fiber, the volume of interaction between drug molecules and laser light is increased compared with conventional methods. Advances in fiber-enhanced Raman spectroscopy point at the high potential for continuous online drug monitoring in clinical therapeutic diagnosis. Furthermore, fiber-array based non-invasive Raman spectroscopic chemical imaging of tablets might find application in the detection of substandard and counterfeit drugs. The discussed techniques are promising and might soon find widespread application for the detection and monitoring of drugs in various fields.

Nano-Structured Optical Fibers Made of Glass-Ceramics, and Phase Separated and Metallic Particle-Containing Glasses

For years, scientists have been looking for different techniques to make glasses perfect: fully amorphous and ideally homogeneous. Meanwhile, recent advances in the development of particle-containing glasses (PCG), defined in this paper as glass-ceramics, glasses doped with metallic nanoparticles, and phase-separated glasses show that these “imperfect” glasses can result in better optical materials if particles of desired chemistry, size, and shape are present in the glass. It has been shown that PCGs can be used for the fabrication of nanostructured fibers—a novel class of media for fiber optics. These unique optical fibers are able to outperform their traditional glass counterparts in terms of available emission spectral range, quantum efficiency, non-linear properties, fabricated sensors sensitivity, and other parameters. Being rather special, nanostructured fibers require new, unconventional solutions on the materials used, fabrication, and characterization techniques, limiting the use of these novel materials. This work overviews practical aspects and progress in the fabrication and characterization methods of the particle-containing glasses with particular attention to nanostructured fibers made of these materials. A review of the recent achievements shows that current technologies allow producing high-optical quality PCG-fibers of different types, and the unique optical properties of these nanostructured fibers make them prospective for applications in lasers, optical communications, medicine, lighting, and other areas of science and industry.

Excitation of epsilon-near-zero resonance in ultra-thin indium tin oxide shell embedded nanostructured optical fiber

We report a novel optical waveguide design of a hollow step index fiber modified with a thin layer of indium tin oxide (ITO). We show an excitation of highly confined waveguide mode in the proposed fiber near the wavelength where permittivity of ITO approaches zero. Due to the high field confinement within thin ITO shell inside the fiber, the epsilon-near-zero (ENZ) mode can be characterized by a peak in modal loss of the hybrid waveguide. Our results show that such in-fiber excitation of ENZ mode is due to the coupling of the guided core mode to the thin-film ENZ mode. We also show that the phase matching wavelength, where the coupling takes place, varies depending on the refractive index of the constituents inside the central bore of the fiber. These ENZ nanostructured optical fibers have many potential applications, for example, in ENZ nonlinear and magneto-optics, as in-fiber wavelength-dependent filters, and as subwavelength fluid channel for optical and bio-photonic sensing.

Failure of nano-structured optical fibers by femtosecond laser procedure as a strain safety-fuse sensor for composite material applications

As shown in a previous paper (Delobelle et al. (2013)) if synthetic flaws are generated on the surface or in the core of optical fibers thanks to single-shot femtosecond laser procedure, the rupture strength of these modified fibers can be controlled.In this paper, numerous new experiments have been conducted to show the potentialities of the embedded structured fibers within composite materials to act as a strain safety fuse sensor. The choice of a multimode optical fiber with polyimide coating has been validated. New Weibull's statistics on short fibers have been determined for two kinds of structuration, flaws on the surface or in the core of the silice fibers and in the failure strains range consistent with sensor applications on composite materials. Long structured fibers have been embedded within plane specimens of two components materials (glass fibers composite (16–20 plane sheets, 0°) and carbon fibers composite (4 sheets, ±45°)) and the comparison between the failure strains of these fibers with those issued from the Weibull's statistics of short fibers shows, at least for the superficial structuration, the possibility to use these structured fibers as strain fuse sensor. A very simple phenomenological model has been proposed.

Fiber optic nanotechnology: a new frontier of fiber optics

Nanophotonics is an exciting new field of nano-science that deals with the interaction of light with matter on a micro/nanometer size scale. It is a field in which photonics merges with nanoscience and nanotechnology, providing challenges for fundamental research and creating opportunities for new technologies and applications. Nanotechnology has spawned new areas of research for fiber optics, namely fiber optic nanophotonics. When we think of optical fibers, we typically think of optical propagation through waveguides of dimensions greater than or similar to the optical wavelength. Conventionally, little attention need be given to sub-wavelength or nano meter size features. However, when nano-features are intentionally incorporated into optical fibers, many interesting phenomena may arise. For example, with nano-features of sufficient refractive index contrast, a properly designed optical fiber can do more than simply guide light from one point to another. Such features can be used to create different types of waveguiding phenomena as well as enabling capabilities for manipulation of light that go beyond conventional optical transport. This additional functionality offers great potential of fiber-based nanotechnology for applications in communications, computation, sensing, biology and chemistry for both waveguides and waveguide-based devices. Nanotechnology can be exploited in multiple ways. In perhaps the most widely recognized form, nano-features provide an additional mechanism for confinement of light in so-called photonic crystal fiber. The concept of using air-glass structures to guide light was proposed in 1974 as a possible design for low-loss optical fiber. However, the field saw little activity until 1996. A major reason for this was because conventional fibers were so successful commercially that most research efforts were focused on exploiting more conventional fibers. Demonstrations of fibers with photonic crystal cladding, and later photonic band-gaps, in the late 1990s reinvigorated the field and attracted new research interest because air-glass microstructures offer a number of interesting physical effects that do not exist in conventional fibers. Microand later nano-structured optical fibers became an extremely active research area while miniaturization pushed toward micro/nanophotonic devices, such as tapers, resonators and interferometer for a wide range of telecommunications and specialty applications.

Failure of multimode optical fibers nano-structured by near ablation threshold single-shot femtosecond laser procedure

The present paper deals with the study of the failure probability of nano-structured optical fibers when submitted to uniaxial tensile loading. A nano-structuration procedure of optical fibers thanks to near ablation threshold single shot femtosecond laser has been proposed. The ablation threshold energy Ep0 for silica fiber is such that: NA2Ep0=15.5nJ, where NA is the numerical aperture of the objective to focus the laser inside the fibers. The rupture strength of the impacted fibers can be controlled through the pulse energy Ep, the numerical aperture NA, the number Nl of nano-craters depending on the step dz of the position of the fiber surface into the focal region, the interval dx between each crater and the number nl of flaw lines. An additive combination of two classical Weibull's laws allows a good representation of the failure probability of the impacted fibers. A phenomenological model for the evolutions of the Weibull's parameters (exponents and scaling stresses) has been proposed and the experimental tendencies of the failure probability curves are fairly well described by the set of the model's equations (Eq. (27)).

Optomechanical Nonlinearity in Dual-Nanoweb Structure Suspended Inside Capillary Fiber

A novel kind of nanostructured optical fiber, displaying an extremely high and optically broadband optomechanical nonlinearity, is presented. It comprises two closely spaced ultrathin glass membranes (webs) suspended in air and attached to the inner walls of a glass fiber capillary. Light guided in this dual-web structure can exert attractive or repulsive pressure on the webs, causing them to be pushed together or pulled apart. The elastic deflection of the webs is, in turn, coupled to the electromagnetic field distribution and results in a change in the effective refractive index within the fiber. Employing a pump-probe technique in an interferometric setup, optomechanically induced refractive index changes more than 10^{4} times larger than the Kerr effect are detected. Theoretical estimates of the optomechanical nonlinearity agree well with the experimental results. The dual-web fiber combines the sensitivity of a microoptomechanical device with the versatility of an optical fiber and could trigger new developments in the fields of nonlinear optics, optical metrology, and sensing.

Remote Surface Enhanced Raman Imaging via a Nanostructured Optical Fiber Array

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Luminescence properties of ytterbium and erbium doped silica–zirconia nanostructured optical fiber under near infrared excitation

We present here the luminescence properties of erbium and ytterbium doped silica–zirconia nanostructured optical fibers prepared by the chemical sol–gel method. After describing the preparation process, their waveguiding properties as well as luminescence properties under continuous pumping in the near infrared domain (NIR) are reported; the effects of the zirconia nanocrystals that are dispersed in the core of the fibers on their optical properties are finally discussed.

Manufacturing Conditions for Microstructured and Nanostructured Optical Fibers

Microstructured optical fiber samples are presented that illustrate the lattice dynamics when fiber-drawing parameters are not ideal. The fiber samples contain simple and complex lattices that exhibit controlled and distorted lattice structures bound by a small (<;0.5) dimensionless capillary number. Although predictive numerical models exist, special manufacturing conditions are required for fabricating novel fiber lattices at limited quantities. This study is useful for basic-research studies on the development of novel lattice structures with characteristically short preform lengths (<;0.5 m) and modest draw rates (<;30 m/min) for the small-volume production of experimental microstructured and nanostructured optical fibers.

Rheology Study of Silica−Zirconia Sols for Elaboration of Silica−Zirconia Nanostructured Optical Fibers by Inverse Dip Coating

This article exposes a study of the rheological properties of silica−zirconia sols in acidic conditions, which are used for the development of nanostructured optical fibers by an original “inverse dip-coating” method. This new generation of optical fibers, which contains zirconia nanocrystals dispersed inside an amorphous pure silica core, must present a homogeneous core to allow good waveguiding properties. Thus, good control of the rheological properties of the silica−zirconia sols at its origin is needed to optimize the development process. After having described the chemical synthesis of the sols, the principle of the rheological measurement is then explained and a short reminder of a few and essential rheological notions is provided. The evolution of the rheological behavior of the sols is then studied as a function of the time and thus as a function of the polymerization advancement. Finally, in order to extend and stabilize the development process of these fibers, an estimation of the sol viscosity...

Light confinement within nanoholes in nanostructured optical fibers

We report fabrication of the lead silicate microstructured fibers (MOFs) with core holes as small as 20 nm, the smallest holes fabricated within the core of an optical fiber to date. We show that light confinement and average mode intensity within such holes are strongly dependent on the hole size. Light confinement within 80 nm and 250 nm core hole within the fabricated MOFs has been experimentally characterized using Scanning Near-field Optical Microscopy (SNOM).

Remote surface enhanced Raman spectroscopy imaging via a nanostructured optical fiber bundle

Remote surface enhanced Raman spectroscopy (SERS) imaging of an adsorbed monolayer was demonstrated through a nanostructured array of conical tips inscribed onto the distal face of a 30 cm optical fiber bundle. Despite intense Raman signal from the germanium oxide doped fibers, the Raman signal of an adsorbed monolayer of a reference compound (benzene thiol) was detected in the fingerprint region. This opens up the possibility of local remote imaging through an optical fiber that embeds a SERS active platform.

Cascade emissions of an erbium-ytterbium doped silica-zirconia nanostructured optical fiber under supercontinuum irradiation

An erbium-ytterbium doped silica-zirconia nanostructured optical fiber is elaborated by using the chemical sol-gel method and its waveguiding properties are studied. A supercontinuum irradiation of the so-fabricated fiber leads to an exotic cascade emission of photons at 515 and 640 nm, as well as a wide emission band between 530 and 590 nm. Upconversion mechanisms and downconversion mechanisms are finally highlighted to explain these phenomena.

Current status of micro- and nano-structured optical fiber sensors

Recently developed micro- and nano-structured optical fiber sensors, with particular reference to surface plasmon resonance (SPR) fiber sensors and photonic crystal fiber (PCF) sensors are reviewed. SPR fiber sensors can have diverse structures such as D-shape, cladding-off, fiber tip or tapered fiber structures. Some of the recently developed novel structures include the use of various types of fiber gratings in SPR fiber sensors. PCF sensors cover diverse recent developments on photonic-bandgap fiber, holey fiber, hole-assisted fiber and Bragg fiber sensors. Major applications of these include gas sensors and bio-sensors. These micro- and nano-structured fiber sensors have attracted considerable research and development interest, because of their distinct advantages, which include high sensitivity, small sensor head footprint and the flexibility of the optical fibers. They are also of academic interest, and many novel ideas are continuously developed.

Multitip-Localized Enhanced Raman Scattering from a Nanostructured Optical Fiber Array

An optical fiber bundle composed of ∼6000 individual 3 μm core diameter fibers has been chemically etched to form a regular array of sharp tips, resulting in the confinement of the light reaching the tip apexes of the fibers as demonstrated by near-field optical microscopy. After coating this nanostructure with a gold thin film (30 nm thick), spatially resolved Raman experiments have been performed to detect a benzenethiol monolayer adsorbed on the covering gold film. High intensity Raman spectra were observed and localized at the extremities of the tips, demonstrating a surface enhanced Raman scattering (SERS) effect induced by the strong curvature of the metallized tip apexes. The Raman enhancement factor of the nanostructure has been investigated and an average enhancement factor of 2.7 × 104 was measured. This opens new avenues for the use of such optical fibers for in situ and endoscopic Raman measurements on complex systems.

MATERIALS SCIENCE BLOSSOMS IN BOSTON

WINTER ARRIVED FASHIONably late to this year's Materials Research Society (MRS) annual meeting, giving conferees three balmy-for-Boston days before settling into the chilly drizzle they've come to expect from the event, held for the past 28 years in Beantown. The season's tardiness was appropriate, though, as fashion took center stage at this year's meeting. During the afternoon breaks on the second and third days of the event, held from Nov. 28 to Dec. 2, attendees were treated to a geek-chic fashion show that featured technologically advanced clothing made possible by materials research. Professional models and MRS student members strutted side by side down the catwalk sporting silver-coated antibacterial textiles, denim jackets equipped with solar cells, and tank tops illuminated by nanostructured optical fibers attached to light-emitting diodes. In the words of Boston Globe reporter Hiawatha Bray, All the clothes showed off recent developments in materials research, an unsexy but vital ...

Micro- and Nano-Structured Optical Fibers - Artificial Media for Amplification of Light.

ABSTRACTIn experiments with rare-earth-doped fibers impressively results have been demonstrated and shown that fiber lasers and amplifiers are an attractive and power scalable solid-state laser concept. With ytterbium-doped large-mode-area double-clad fibers, output powers approaching the kW-range with diffraction limited beam quality have been realized in the continuous regime. Also in the pulsed regime, even for femtosecond pulse duration average output powers in the range of 100 W have been demonstrated. Further power scaling is limited by the end facets damage, thermo-optical problems or nonlinear effects. To overcome these restrictions microstructured fibers can be used. This type of fibers has several new preferable features. In our contribution we will discuss the advantages of microstructured fibers to reduce nonlinear effects inside the fiber and the possibility to scale the output power of fiber lasers and amplifiers with excellent beam quality. We also show fiber based chirped pulse amplification system (CPA-System) with ultra short pulses, pulse energies of up to 100 μJ and high repetition rates.