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To combine the technical functions and advantages of solid-core fiber Bragg gratings (FBGs) and hollow-core optical fibers (HCFs), the hollow and filled FBGs in nano-bore optical fibers (NBFs) with nano-bore in the GeO2-doped core are proposed. The fundamental mode field, effective mode index, and confinement loss of NBF with 50 nm–-diameter hollow and filled nano-bore are numerically investigated by the finite element method. The reflected spectra of FBGs in NBFs are obtained by the transmission matrix method. The hollow FBGs in NBFs can be acheived with (∼5% power fraction in the bore and the (∼0.9 reflectivity when bore diameter is less than . The filled FBGs can be realized with (∼1% power fraction and 0.98 reflectivity with different fillings including o-xylene, trichloroethylene, and chloroform for 800-nm bore diameter. The feasibility of the index sensing by our proposed NBF FBG is also analyzed and discussed. The experimental fabrication of hollow and filled FBGs are discussed and can be achieved by current techniques. The aim of this work is to establish a principle prototype for investigating the HCFs and solid-core FBGs-based fiber-optic platforms, which are useful for applications such as the simultaneous chemical and physical sensing at the same position. [ABSTRACT FROM AUTHOR]

Large-area patterned films of boron nanowires (BNWs) are fabricated at various densities by chemical vapor deposition (CVD). Different widths of unit-cell of Mo masks are used as templates. The widths of unit-cell of Mo masks are 100 μm, 150 μm, and 200 μm, respectively. The distance between unit cells is 50 μm. The BNWs have an average diameter of about 20 nm and lengths of 10 μm–20 μm. High-resolution transmission electron microscopy analysis shows that each nanowire has a β-tetragonal structure with good crystallization. Field emission measurements of the BNW films show that their turn-on electric fields decrease with width of unit-cell increasing. [ABSTRACT FROM AUTHOR]

Large-area boron nanowire (BNW) films were fabricated on the Si(111) substrate by chemical vapor deposition (CVD). The average diameter of the BNWs is about 20 nm, with lengths of 5–10 μm. Then, graphene-capped boron nanowires (GC-BNWs) were obtained by microwave plasma chemical vapor deposition (MPCVD). Characterization by scanning electron microscopy indicates that few-layer graphene covers the surface of the boron nanowires. Field emission measurements of the BNWs and GC-BNW films show that the GC-BNW films have a lower turn-on electric field than the BNW films. [ABSTRACT FROM AUTHOR]