Search results for "OPTICS"
showing 10 items of 10033 documents
High-Sensitivity Whispering Gallery Mode Humidity Sensor Based on Glycerol Microdroplet Volumetric Expansion
2021
We demonstrate a highly sensitive whispering gallery mode (WGM) relative humidity (RH) sensor based on a glycerol microdroplet. WGMs were excited using a 760 nm tunable semiconductor laser. We used free space coupling, which is effective when using a liquid resonator. A detailed analysis of different parameters influencing the sensor’s characteristics (sensitivity, hysteresis, resolution, stability, and temperature) is presented. The sensitivity of the sensor is one of the highest reported (2.85 nm/% RH in the range 50–70% RH with the resolution 1 × 10−4% RH). This type of humidity sensor has several advantages, such as high sensitivity, extended lifetime, good repeatability, and low cost, …
Understanding tungsten erosion during inter/intra-ELM periods in He-dominated JET-ILW plasmas
2021
Tungsten erosion was quantified during inter/intra-ELM periods in He-dominated JET-ILW plasmas by optical emission spectroscopy. The intra-ELM tungsten sputtering in helium plasmas, which dominates the total W source, prevails by a factor of about 4 over inter-ELM sputtering in the investigated ELM frequency range from 90 Hz-120 Hz. He ions are mainly responsible for the W erosion during the ELMs in He plasmas. The strong in/out asymmetry of the ELM-induced W erosion is observed in He plasmas even at high ELM frequencies beyond 100 Hz. In Ohmic/L-mode plasmas and during the H-mode inter-ELM plasma phases both He2+ and Be2+ ionic species are major contributors to the W erosion. Their contrib…
The MARA-LEB ion transport system
2020
A low-energy branch is under development for the MARA vacuum-mode recoil separator at the Accelerator Laboratory of the University of Jyväskylä. This development will allow for the study of proton-rich nuclei through laser ionisation spectroscopy and mass measurements. After stopping and extraction from a buffer gas cell, the ions of interest will be accelerated and transported to dedicated experimental setups by an ion transport system consisting of several focusing, accelerating and mass-separating elements. This article presents the current design and simulations for the ion transport. peerReviewed
A Computationally Efficient Online/Offline Signature Scheme for Underwater Wireless Sensor Networks
2022
Underwater wireless sensor networks (UWSNs) have emerged as the most widely used wireless network infrastructure in many applications. Sensing nodes are frequently deployed in hostile aquatic environments in order to collect data on resources that are severely limited in terms of transmission time and bandwidth. Since underwater information is very sensitive and unique, the authentication of users is very important to access the data and information. UWSNs have unique communication and computation needs that are not met by the existing digital signature techniques. As a result, a lightweight signature scheme is required to meet the communication and computation requirements. In this researc…
A new forum for upconversion research: The UPCON conference
2019
International audience; The Conference and Spring School on Properties, Design and Applications of Upconversion Nanomaterials (UPCON) provides a new forum for all experts and newcomers in the field of upconversion research. On the occasion of the second UPCON 2018 in Valencia (Spain), we are pleased to present a collection of 12 reviews and research articles that reflect recent advances in upconversion materials, their unique luminescent properties and many applications spanning from nanoscale thermometry to biomedicine.
Interaction between surface plasmon polaritons and molecules in strong coupling limit
2016
Miniaturization of optical elements and their integration to electronic circuits is limited by diffraction limit. It was realized that light being coupled to surface plasmons (SP) can overcome this limit. Employing also optically active molecules in combination with SPs can drive optical circuits to nm-scale and add functionalities. For efficient performance of plasmonic elements involving fluorescent dye molecules investigation of physics behind their interaction is of high priority. In this thesis interaction between surface plasmon polaritons (SPPs) and different dye molecules has been studied, especially within strong coupling limit, which brings in totally new physical properties in th…
Theory of phase-mixing amplification in an optomechanical system
2017
The investigation of the ultimate limits imposed by quantum mechanics on amplification represents an important topic both on a fundamental level and from the perspective of potential applications. We discuss here a novel regime for bosonic linear amplifiers—beside phase-insensitive and phase-sensitive amplification—which we term here phase-mixing amplification. Furthermore, we show that phase-mixing amplification can be realised in a cavity optomechanical setup, constituted by a mechanical resonator which is dispersively coupled to an optomechanical cavity asymmetrically driven around both mechanical sidebands. While, in general, this amplifier is phase-mixing, for a suitable choice of para…
Highly Sensitive Polarization Rotation Measurement through a High‐Order Vector Beam Generated by a Metasurface
2020
The precise determination of the polarization state of light is fundamental for a vast variety of applications in remote sensing, astronomy, optics and terahertz technology, to name just a few. Typically, polarization characterization is performed by using a combination of multiple optical devices such as beam splitters, polarizers, and waveplates. Moreover, to achieve high-precision, balanced photodetectors and lock-in amplifiers are employed, thus contributing to increasing system complexity. Here, a technique for polarization rotation measurements with a dynamic range of 180° and a sensitivity of about 10−2 degrees is realized using a properly designed metasurface. Such device generates …
Applying Axial Symmetries to Historical Silk Fabrics: SILKNOW’s Virtual Loom
2020
Symmetry is part of textile art in patterns and motifs that decorate fabrics, which are made by the interlacement of warp and wefts. Moreover, the 3D representation of fabrics have already been studied by some authors
Motion perception in early glaucoma
2013
Purpose: The aim of our study was to underline the changes in the movement perception for early glaucoma. Our working hypothesis consisted in inquiring if the impairment of the magnocellular pathway may modify the movement perception capabilities in the visual field, more particularly in its peripheral area.Methods: We included 14 healthy subjects and 14 patients with early primary open angle glaucoma. A moving target was presented on a semicircular screen (1.8 m diameter); participants were asked to localize the Ending Point (EP) of each movement. Each stimulus consisted in a white dot (0,72° of diameter) moving horizontally with the imposed velocity profile. Two different laws of motion w…