Highly efficient surface enhanced Raman scattering using microstructured optical fibers with enhanced plasmonic interactions

Microstructured optical fibers "MOFs" represent a promising platform technology for fully integrated photonic-plasmonic devices. In this paper, we experimentally investigate the properties of two MOF templates impregnated with silver nanoparticles via a high pressure chemical deposition technique. By comparing fiber templates with different air filling fractions, we have quantified the importance of an increased field-particle overlap for improved surface enhanced Raman scattering sensitivity for the next generation of optical fiber sensors

Thermal nonlinearity in silicon microcylindrical resonators

We explore the thermally induced nonlinearity in hydrogenated amorphous silicon microcylindrical resonators that are fabricated from the silicon optical fiber platform. In particular, we use a pump-probe technique to experimentally demonstrate thermally induced optical modulation and determine the response time. Through characterization of the thermal properties and the associated resonance wavelength shifts we will show that it is possible to infer the material absorption coefficient for a range of whispering gallery mode resonators

Time and spectrally resolved enhanced fluorescence using silver nanoparticle impregnated polycarbonate substrates

Silver nanoparticle impregnated polycarbonate strips have been investigated as substrates for metal-enhanced photoluminescence of a blue emitting dye molecule (coumarin 102). By considering simultaneous time and spectrally resolved photoluminescence we observed fluorescence enhancement resulting from plasmon coupling with an increase in the emission by a factor of ~8.5 with an associated reduction in the photon lifetime. We relate the fast and slow components of the observed emission decay to the presence of both monomers and aggregates in the films and we discuss their different responses to the plasmon coupling

Incorporating metal organic frameworks within microstructured optical fibers toward scalable photoreactors

Optical fiber technology has revolutionized the telecommunications industry, though is still under‐utilized in chemistry. Optical fibers open many avenues for introducing, and containing, light in chemical reactions, as part of a photoreactor. This work shows, for the first time, a design strategy for incorporating a photocatalytic, nanoporous framework (Co ZIF‐67) within the internal capillaries of an optical fiber, in doing so creating an all‐in‐one, plug‐in‐and‐play photoreactor. This system improves the reactivity of the photocatalyst, relative to the powdered form, for C—H activation leading to C—C bond formation, a significant process in pharmaceutical and organic synthesis. Performing this reaction using solar energy, and low temperature demonstrates the clear potential for these systems for large scale industrial applications

Templated growth of II-VI semiconductor optical fiber devices and steps towards infrared fiber lasers

ZnSe and other zinc chalcogenide semiconductor materials can be doped with divalent transition metal ions to create a mid-IR laser gain medium with active function in the wavelength range 2-5 microns and potentially beyond using frequency conversion. As a step towards fiberized laser devices, we have manufactured ZnSe semiconductor fiber waveguides with low (less than 1dB/cm at 1550nm) optical losses, as well as more complex ternary alloys with ZnSxSe1-x stoichiometry to potentially allow for annular heterostructures with effective and low order mode core-cladding waveguiding

Continuous wave Fe²⁺:ZnSe mid-IR optical fiber lasers

Today fiber lasers in the visible to near-infrared region of the spectrum are well known, however mid-infrared fiber lasers have only recently approached the same commercial availability and power output. There has been a push to fabricate optical fiber lasers out of crystalline materials which have superior mid-IR performance and the ability to directly generate mid-IR light. However, these materials cannot currently be fabricated into an optical fiber via traditional means. We have used high pressure chemical vapor deposition (HPCVD) to deposit Fe2+:ZnSe into a silica optical fiber template. These deposited structures have been found to exhibit laser threshold behavior and emit CW mid-IR laser light with a central wavelength of 4.12 μm. This is the first reported solid state fiber laser with direct laser emission generated beyond 4 μm and represents a new frontier of possibility in mid-IR laser development.+<br/

Diamond encapsulated silicon optical fibers synthesized by chemical vapor deposition

Semiconductor optical fibers encapsulated in a protective diamond coating can theoretically lead to immense power handling capabilities and infrared functionality. Here, silicon optical fibers are grown using high pressure chemical vapor deposition before being coated by 50 μm-300 μm of diamond by microwave plasma-assisted chemical vapor deposition. This coating extends conformally around the fiber cross section with diamond crystallites in the film on the order of several micrometers. Complete coating of high-quality diamond around the fiber is indicated by scanning electron microscopy and Raman measurements. The encapsulated silicon fibers are durable enough to survive the diamond deposition process, as demonstrated by their ability to guide infrared light