Progress in neuroscience constantly relies on the development of new techniques to investigate complex dynamics neuronal networks. An ongoing challenge is achieve minimally-invasive and high-resolution observations activity vivo inside deep brain areas. A perspective strategy utilise holographic control light propagation media, which allows converting a hair-thin multimode optical fibre into an ultra-narrow imaging tool. Compared current endoscopes based GRIN lenses or bundles, this concept...

Digital micro-mirror devices (DMDs) have recently emerged as practical spatial light modulators (SLMs) for applications in photonics, primarily due to their modulation rates, which exceed by several orders of magnitude those the already well-established nematic liquid crystal (LC)-based SLMs.This, however, comes at expense limited depth and diffraction efficiency.Here we compare beam-shaping fidelity both technologies when applied control complex environments, including an aberrated optical...

Holographic wavefront manipulation enables converting hair-thin multimode optical fibres into minimally invasive lensless imaging instruments conveying much higher information densities than conventional endoscopes. Their most prominent applications focus on accessing delicate environments, including deep brain compartments, and recording micrometre-scale resolution images of structures in close proximity to the distal end instrument. Here, we introduce an alternative 'farfield' endoscope,...

Acoustic sensing is nowadays a very demanding field which plays an important role in modern society, with applications spanning from structural health monitoring to medical imaging. Fiber-optics can bring many advantages this field, and fiber-optic acoustic sensors show already performance levels capable of competing the standard based on piezoelectric transducers. This review presents recent advances dynamic strain sensing, particularly for detection. Three dominant technologies are...

An effective analytical model combining geometrical optics with the transfer-matrix theory for stratified optical media is applied to investigate sensing properties of tapered fiber surface plasmon resonance (SPR) sensors incorporating Ag–Au bimetallic layers, particularly in context phase interrogation. The performance structures studied as a function tapering parameters and thickness metallic layers. It shown that combination capable improving resolution tuning working region SPR...

In-vivo microendoscopy in animal models became a groundbreaking technique neuroscience that rapidly expands our understanding of the brain. Emerging hair-thin endoscopes based on multimode fibres are now opening up prospect ultra-minimally invasive neuroimaging deeply located brain structures. Complementing these advancements with methods functional imaging and optogenetics, as well extending its applicability to awake motile animals constitute most pressing challenges for this technology....

Microendoscopes based on optical fibres have recently come to the fore as promising candidates allowing in-vivo observations of otherwise inaccessible biological structures in animal models. Despite being still its infancy, imaging can now be performed at tip a single multimode fibre, by relying powerful holographic methods for light control. Fibre endoscopy is commonly en face , resulting possible damage specimen owing direct contact between distal end probe and target. On this ground, we...

Computer-controlled spatial modulation of coherent light has enabled multiple new ways imaging through complex media. MEMS-based digital micromirror devices (DMDs) employed as modulators present considerably higher display frame rates compared to the popular alternative based on liquid crystal technology. For a progress beyond laboratory conditions, hologram projected with DMD needs remain time-invariant after wavefront correction. The thermal load when operating at highest is one main...

Abstract Over the past decade, optical wavefront shaping has been developed to focus light through highly opaque scattering layers, opening new possibilities for biomedical applications. To probe intensity deep inside soft media such as biological tissues, internal guide-stars are required. Here, we give an overview of main principles and describe in depth use a photoacoustic feedback signal this purpose. We further present first calculations simulations estimate important experimental...

Abstract Optical fiber optrodes are attractive sensing devices due to their ability perform point measurement in remote locations. Mostly, they oriented biochemical sensing, quite often supported by fluorescent and spectroscopic techniques, but with the refractometric approach considered as well when objective is of high performance, particularly focus on enhancing measurand resolution. In this work, we address subject, proposing analyzing characteristics a optic optrode relying plasmonic...

A palladium (Pd)-based optical metamaterial has been designed, fabricated and characterized for its application in hydrogen sensing. The can replace Pd thin films transmission schemes sensing with performances far superior to those of conventional sensors. This artificial material consists a palladium–alumina using inexpensive industrial-friendly bottom-up techniques. During the exposure hydrogen, system exhibits anomalous absorption when compared well-known response films, this phenomenon...

Abstract This Letter reports on the assembly tip of an optical fibre a metamaterial film fabricated by self‐assembly bottom‐up method, composed silver nanowires embedded in alumina matrix. By illuminating through reflection configuration, we observe experimentally response agreement with theoretical predictions and interpreted as excitation surface plasmon‐polaritons cylindrical nanowires. These results pave way for low‐cost devices that incorporate films. magnified image Micrographs...

Abstract There has been a tremendous effort in modern microscopy towards miniaturisation and fibre-based technology, driven by the need to access hostile or difficult environments situ vivo. Most of these rely on reducing size endoscopes based fibre-optic bundles, systems incorporating microfabricated lenses. Recently, use standard multimode optical fibres for lensless become possible mainly due advances holographic beam shaping. This article reviews methods techniques behind this progress...

Photoconductive antennas deposited onto GaAs substrates that incorporate InAs quantum dots have been recently shown to efficiently generate both pulsed and CW terahertz radiation. In this Letter, we determine the operational limits of these demonstrate their extreme thermal breakdown tolerance. Implanted serve as free carrier capture sites, thus acting lifetime shorteners, similar defects in low-temperature grown substrates. However, unlike latter, defect-free quantum-dot structures possess...

In this work, we address a study of the spectral reflectance silver nanowire metamaterials in visible and near-infrared regions. To end, several samples were fabricated with different fill-ratios lattice constants, their respective optical responses characterized terms these parameters. We perform direct comparison between collected experimental data values predicted by analytical homogenization models to provide better understanding effective behavior kind metamaterials.

This paper investigates numerically the performance of a design for an optical sensor refractive index gases and liquids based on smart or functional metamaterial films (smart metamembranes).

An analytical model based on geometrical optics and multilayer transfer matrix method is applied to determine the sensing properties of tapered optical fiber SPR sensors incorporating bimetallic (Gold Silver) layers, particularly when phase interrogation considered. Phase studied as a methodology attain enhanced sensitivities. The performance heads function layers taper parameters analyzed. It shown combination capable provide larger values sensitivity compared with single layer approach....

An analytical model based on geometrical optics and multilayer transfer matrix method is applied to the surface plasmonic resonance supported by fibre taper structures in context of optical sensing applications. Phase interrogation considered particular as a methodology attain enhanced sensitivities, performance heads function metal clad parameters analyzed. General topics concerning actual relevance plasmonics are also presented, first global perspective then when sensing.

Over the past decade, optical wavefront shaping has been developed to focus light through highly opaque scattering layers, opening new possibilities for biomedical applications. To probe intensity deep inside soft media such as biological tissues, internal guide-stars are required. Here, we give an overview of main principles and describe in depth use a photoacoustic feedback signal this purpose. We further present first calculations simulations estimate important experimental parameters,...

This work reports the theoretical investigation of optical fiber surface plasmon resonance sensors incorporating bimetallic layer combinations. Different metals like silver, gold, copper, and aluminum are considered to investigate refractometric sensing properties tapered tip optrode phase-interrogated plasmonic sensor structures. It is shown that gold–silver combination, coupled a layout, capable maximizing resolution operation range these structures for environmental refractive index measurement.

One of the major issues in modeling subwavelength optical materials resides how to compute effective properties such media. An efficient technique must be able describe appropriately electromagnetic response overall structure. Within this context, work is focused on calculation parameters metallic silver nanowires embedded alumina background. algorithm based modal propagation considered order estimate refractive index at visible spectrum. The resonances obtained computing model are compared...

In this work we show numerically the potential of using a metamaterial constituted by ordered arrays silver nanowires as sensor for refractive index changes surrounding dielectric medium. The results strong dependence reflectance spectrum on