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Disordered optical fibers show novel waveguiding properties, enabled by the transverse Anderson localization of light, and are used for image transport. The strong transverse scattering from the transversely disordered refractive index structure results in transversely confined modes that can freely propagate in the longitudinal direction. In some sense, an Anderson localization disordered fiber behave like a large-core multimode optical fiber, with the advantage that most modes are highly localized in the transverse plane, so any point in the cross section of the fiber can be used for localized beam transport. This property has been used for high-quality transportation of intensity patterns and images in these optical fibers. This review covers the basics and the history of the transverse Anderson localization in disordered optical fibers and captures the recent progress in imaging applications using these optical fibers. [ABSTRACT FROM AUTHOR]

We describe the design and ground-based performance of the two-color calibration lamp for the Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI) instrument on the NASA Ionospheric Connection (ICON) satellite. The calibration lamp assembly contains radio frequency excited krypton and neon lamps, which generate emission lines at 557 and 630 nm, respectively, and which are used to monitor thermal drifts in the two MIGHTI Doppler asymmetric spatial heterodyne interferometers. The lamps are coupled to two mixed optical fiber bundles that deliver the calibration signals to the two MIGHTI optical units. The assembly starts reliably, consumes <8 W, and has passed environmental testing for the ICON satellite. The total mass of the lamp assembly is 1.8 kg. Special features of the assembly and its implementation are described along with results of life tests. [ABSTRACT FROM AUTHOR]

Photoplethysmography (PPG) is a widely used technique for measuring blood oxygen saturation, commonly using an external pulse oximeter applied to a finger, toe, or earlobe. Previous research has demonstrated the utility of direct monitoring of the oxygen saturation of internal organs, using optical fibers to transmit light between the photodiode/light emitting diode and internal site. However, little research into the optimization and standardization of such a probe has yet been carried out. This research establishes the relationship between fiber separation distance and PPG signal, and between fiber core width and PPG signal. An ideal setup is suggested: 1000-μm fibers at a separation distance of 3 to 3.5 mm, which was found to produce signals around 0.35 V in amplitude with a low variation coefficient. [ABSTRACT FROM AUTHOR]

This review focuses on the role that micro and nanotechnologies are having in the development of a new generation of optical neural interfaces for deep brain regions. The advent of optical methods to control and monitor neural activity has indeed raised neuroscientists' demand for small, soft and multifunctional devices to interface with sub-cortical structures. These are indeed widely inaccessible with microscopy-based approaches, and the scientific community has proposed complementary methods based on integrated photonics, implantable micro LEDs and engineered optical fibers. After discussing advantages and drawbacks of these methods, the manuscript closes with an overview on the emerging field of optical neural interfaces based on colloidal nanoparticles. Unlabelled Image • Micro and nanotechnologies are a key for next generation of optical neural interfaces. • Integrated photonics is one of the main roads to realize fully integrated devices. • Implantable μLEDs allow for wireless optical stimulation of neural activity. • Engineered optical fibers reach sub-cortical structures with reduced invasiveness. • Nanoparticles bring quantum confinement and light-matter interactions in the brain. [ABSTRACT FROM AUTHOR]