BACKGROUND For most people with low vision, some form of magnification is necessary to read. Using a magnifier reduces the number of letters that can be seen simultaneously (field of view), which has been shown to decrease reading rates. This study sought to determine how many letters are necessary to attain maximal reading rates with a stand magnifier. METHODS Younger and older normally-sigh...

Efficient coupling between a localized quantum emitter and a well defined optical channel represents a powerful route to realize single-photon sources and spin-photon interfaces. The tailored fiber-like photonic nanowire embedding a single quantum dot has recently demonstrated an appealing potential. However, the device requires a delicate, sharp needle-like taper with performance sensitive to ...

Adiabatically tapered holey fibers are shown to be potentially useful for guided-wave spot-size and numerical aperture conversion. Conditions for adiabaticity and design guidelines are provided in terms of the effective index model. We also present finite-difference time-domain calculations of down-tapered holey fiber, showing that large spot size conversion factors are obtainable with minimal ...

Cladded multimode fiber optic tapers are proposed as chemical sensors using evanescent wave absorption. There is no need to strip the cladding; therefore, fabrication is easy and the taper is mechanically stronger than the taper without cladding. The transmission property and evanescent wave absorption are modeled using ray theory and wave theory, respectively. Effects of some parameters on the...

purpose : to determine the nerve fiber layer and macular thickness by optical coherence tomography (oct) in emmetropic, high-myopic and high-hyperopic eyes methods : one hundred five eyes of 55 randomly selected healthy subjects between 20 and 30 years old were included in this study. the eyes were categorized in three groups (high-myopic, emmetropic and high-hyperopic) according to their cyclo...

This study presents a full-duplex Radio-over-Fiber (RoF) system providing the users' wireless access with a bit rate of 10 Gbps over 40 GHz radio carrier. This system can be used in a centralized radio access network (C-RAN) architecture because we provide a fully analog front haul link between central station and base station. We can consider it as infrastructure between remote radio heads (RR...

A ring-resonator-based refractive index sensor is proposed in this paper. Glass filaments with surface guiding layers created by ion exchange are crossed with a fiber taper to act as a ring resonator sensor. Theoretical simulation of the sensor response is proposed, and optimization of structural parameters including thickness and refractive index of the surface guiding layer and the diameter o...

In this work we describe the fabrication and the characterization of perfluorinated plastic-cladded optical fiber tapers. The heat-and-pull procedure has been used to fabricate symmetric tapers. Devices with different taper ratio have been produced and the repeatability of the process has been verified. The very low refractive indexes of the core-cladding perfluorinated polymers (n = 1.35-1.34)...

We report on single rolled-up microtubes integrated with silicon-on-insulator waveguides. Microtubes with diameters of ~7 μm, wall thicknesses of ~250 nm, and lengths greater than 100 μm are fabricated by selectively releasing a coherently strained InGaAs/GaAs quantum dot layer from the handling GaAs substrate. The microtubes are then transferred from their host substrate to silicon-on-insulato...

Ultrasensitive nanoparticle detection holds great potential for early-stage diagnosis of human diseases and for environmental monitoring. In this work, we report for the first time, to our knowledge, single nanoparticle detection by monitoring the beat frequency of split-mode Raman lasers in high-Q optical microcavities. We first demonstrate this method by controllably transferring single 50-nm...