7,967 research outputs found
Single-crystal semiconductor wires integrated into microstructured optical fibers
No full textAssembly and integration of photonic and electronic building blocks such as semiconductor micro/nanowires into more complex structures is critical to the realization of advanced materials and devices useful for a diverse range of applications
Building semiconductor structures in optical fiber
No full textFabrication of semiconductor devices inside microstructured optical fiber may lead to all-fiber optoelectronics. In addition, the pervasive nature of electronics and optoelectronics technology based on silicon, GaAs and other crystalline semiconductors is familiar to almost all scientists and engineers...
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Infrared fibers
No full textAbstract not availableGuangming Tao, Heike Ebendorff-Heidepriem, Alexander M. Stolyarov, Sylvain Danto, John V. Badding, Yoel Fink, John Ballato, and Ayman F. Abouradd
Experimental observation of whispering gallery modes in novel silicon microcylindrical resonators
No full textMicroresonators that support whispering gallery modes (WGMs) are ideal systems for studying nonlinear phenomena at low thresholds due to the small mode volumes and the high quality (Q) factors and, as such, they are currently generating much scientific interest [1]. A variety of geometries have been investigated including microspheres, microdisks, toroids and micropillars, using a range of dielectrics and, more recently, semiconductor materials. One of the major challenges in fabricating semiconductor microresonators is obtaining the smooth, defect-free, surfaces required for high Q operation. In this paper, we present a novel approach to fabricating high quality silicon microcylindrical resonators starting from the silicon optical fibre platform [2]. The silicon fibres are fabricated using a high pressure chemical deposition technique to fill silica capillaries with the semiconductor material. This process can be easily modified to fill capillaries of various internal diameters with the deposited material taking on the pristine smoothness of the capillary walls (0.1 nm RMS). As an optical material, silicon is particularly attractive due to its broad transparency window that extends from the telecoms band to the mid-IR (~1.2–7µm), as well as its high optical damage threshold and large nonlinearities
Templated chemically deposited semiconductor optical fiber materials
No full textChemical deposition is a powerful technology for fabrication of planar microelectronics. Optical fibers are the dominant platform for telecommunications, and devices such as fiber lasers are forming the basis for new industries. High-pressure chemical vapor deposition (HPCVD) allows for conformal layers and void-free wires of precisely doped crystalline unary and compound semiconductors inside the micro-to-nanoscale-diameter pores of microstructured optical fibers (MOFs). Drawing the fibers to serve as templates into which these semiconductor structures can be fabricated allows for geometric design flexibility that is difficult to achieve with planar fabrication. Seamless coupling of semiconductor optoelectronic and photonic devices with existing fiber infrastructure thus becomes possible, facilitating all-fiber technological approaches. The deposition techniques also allow for a wider range of semiconductor materials compositions to be exploited than is possible by means of preform drawing. Gigahertz bandwidth junction-based fiber devices can be fabricated from doped crystalline semiconductors, for example. Deposition of amorphous hydrogenated silicon, which cannot be drawn, allows for the exploitation of strong nonlinear optical function in fibers. Finally, crystalline compound semiconductor fiber cores hold promise for high-power infrared light-guiding fiber devices and subwavelength-resolution, large-area infrared imaging
Endoscopic fiber: microfluidic chemical deposition moves optical fiber to the nanoscale
No full textThe use of a novel chemical vapor-deposition process to integrate metals and semiconductor films in microstructured optical fibers may soon enable nanometer-scale waveguides and endoscopic cameras
Drones, augmented reality and virtual reality journalism: mapping their role in immersive news content
No full textDrones are shaping journalism in a variety of ways including in the production of immersive news content. This article identifies, describes and analyzes, or maps out, four areas in which drones are impacting immersive news content. These include: 1) enabling the possibility of providing aerial perspective for first-person perspective flight-based immersive journalism experiences; 2) providing geo-tagged audio and video for flight-based immersive news content; 3) providing the capacity for both volumetric and 360 video capture; and 4) generating novel content types or content based on data acquired from a broad range of sensors beyond the standard visible light captured via video cameras; these may be a central generator of unique experiential media content beyond visual flight-based news content
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Polycrystalline silicon optical fibers with atomically smooth surfaces
No full textWe investigate the surface roughness of polycrystalline silicon core optical fibers fabricated using a high-pressure chemical deposition technique. By measuring the optical transmission of two fibers with different core sizes, we will show that scattering from the core–cladding interface has a negligible effect on the losses. A Zemetrics ZeScope three-dimensional optical profiler has been used to directly measure the surface of the core material, confirming a roughness of only ±0.1nm. The ability to fabricate low-loss polysilicon optical fibers with ultrasmooth cores scalable to submicrometer dimensions should establish their use in a range of nonlinear optical application
Ultra-smooth microcylindrical resonators fabricated from the silicon optical fiber platform
No full textWe demonstrate a type of microcavity with minimal-volume confinement using a high-contrast phase-shifted Bragg grating in a microfiber. While waveguiding by the air-silica boundary provides a diffraction-limited two-dimensional confinement, the grating introduces the third degree of confinement. Theoretical simulations verified the microfiber cavity confinement while the experimental demonstration, carried out in samples nanostructured by focused ion beam, showed a good agreement with theoretical predictions. This cavity can be used for a variety of applications ranging from sensing to quantum dynamic experiments
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