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We demonstrate potential molecular monolayer detection using measurements of surface plasmon resonance (SPR) and angular Goos-Hänchen (GH) shift. Here, the molecular monolayer of interest is a benzenethiol self-assembled monolayer (BT-SAM) adsorbed on a gold (Au) substrate. Excitation of surface plasmons enhanced the GH shift which was dominated by angular GH shift because we focused the incident beam to a small beam waist making spatial GH shift negligible. For measurements in ambient, the presence of BT-SAM on a Au substrate induces hydrophobicity which decreases the likelihood of contamination on the surface allowing for molecular monolayer sensing. This is in contrast to the hydrophilic nature of a clean Au surface that is highly susceptible to contamination. Since our measurements were made in ambient, larger SPR angle than the expected value was measured due to the contamination in the Au substrate. In contrast, the SPR angle was smaller when BT-SAM coated the Au substrate due to the minimization of contaminants brought about by Au surface modification. Detection of the molecular monolayer acounts for the small change in the SPR angle from the expected value.

We have implemented three different optical methods to quantitatively assess the thickness of thin GaSe flakes transferred on both transparent substrates, like Gel-Film, or SiO2/Si substrates. We show how their apparent color can be an efficient way to make a quick rough estimation of the thickness of the flakes. This method is more effective for SiO2/Si substrates as the thickness dependent color change is more pronounced on these substrates than on transparent substrates. On the other hand, for transparent substrates, the transmittance of the flakes in the blue region of the visible spectrum can be used to estimate the thickness. We find that the transmittance of flakes in the blue part of the spectrum decreases at a rate of 1.2%/nm. On SiO2/Si, the thickness of the flakes can be accurately determined by fitting optical contrast spectra to a Fresnel law-based model. Finally, we also show how the quantitative analysis of transmission mode optical microscopy images can be a powerful method to quickly probe the environmental degradation of GaSe flakes exposed to aging conditions., Comment: 5 figures

At any time of the day, a spherical mirror reflects the rays coming from the sun along a line that points to the sun through the center of the sphere. This makes it possible to build concentrated solar power(CSP) plants with fixed solar fields and mobile receivers; that is, solar fields can be significantly cheaper and simpler, but challenging tracking systems for the mobile receiver need to be implemented. The cost-cutting possibilities for this technology have been under-researched. This article describes the MOSAIC concept, which aims to achieve low-cost solar energy by boosting the benefits of spherical reflectors while addressing their challenges. This new concept proposes to build large modular plants from semi-Fresnel solar bowls. One of these modules has been designed and is under construction in Spain. This article reports the main lessons learned during the design phase, describes the advantages and challenges of the concept, details the proposed routes to overcome them, and identifies the steps needed to develop a fully competitive industrial solution.

Fresnel reflection on a water surface is highly variable throughout the year and can have a significant influence on building-integrated vertical PV panels, yet is generally disregarded in yield calculations. We analyze beam irradiances of two horizontal pyranometers situated next to a lake, one facing upwards and one facing downwards, to estimate the contribution of Fresnel reflection to the beam irradiance on a vertical surface. We show that in general the observed beam irradiance on the downward facing instrument matches the calculated Fresnel reflection. In contrast to other studies investigating water albedo, we also found that the reflection percentage decreases consistently with higher wind speeds and lower solar zenith angle. Fresnel reflection has the highest contribution for vertical surfaces in winter, with varying contributions between 30% of monthly global irradiance over the course of one year for different latitudes, and should thus be included in yield estimates for building integrated PV installations situated next to bodies of water.

We demonstrate a 3D printed holographic metasurface antenna for beam-focusing applications at 10 GHz within the X-band frequency regime. The metasurface antenna is printed using a dual-material 3D printer leveraging a biodegradable conductive polymer material (Electrifi) to print the conductive parts and polylactic acid (PLA) to print the dielectric substrate. The entire metasurface antenna is 3D printed at once; no additional techniques, such as metal-plating and laser etching, are required. It is demonstrated that using the 3D printed conductive polymer metasurface, high-fidelity beam focusing can be achieved within the Fresnel region of the antenna. It is also shown that the material conductivity for 3D printing has a substantial effect on the radiation characteristics of the metasurface antenna.

Within the FP7-InSun project three different solar process heat systems have been installed and integrated in two different industrial processes. A 1067 m 2 advanced flat plate collector field and a 130 m 2 parabolic trough system have been installed at a ham and sausage production in Austria to preheat the feed water of a steam boiler and to prepare hot water for cleaning and drying processes. A 2640 m 2 Fresnel collector field installed at a brick fabrication in Italy produces steam at 180 °C and 12 bars to heat air for a brick drying process. In this paper the experiences made during planning, installation, commissioning and regular system operation will be described and discussed together with measured performance data. Furthermore, system costs and cost improvements reached by optimization in the collector production and standardization of system integration devices are shown and discussed together with future application potentials on the basis of detailed simulation studies carried out during the project.

A scheme for wireless power transfer (WPT) in the radiative near-field (Fresnel) region is presented. The proposed Fresnel WPT scheme is designed to focus microwaves to a diffraction- limited region where a detector can be positioned, achieving reasonably high power transfer efficiency over moderate distances. The configuration consists of transmit and receive microstrip patch array antennas, with the receiving antenna connected to a power- harvesting half-wave rectifier (rectenna). Fresnel region operation enables the fields radiated by the transmitting aperture to be localized both in range and cross-range. Using Fresnel region focusing, we achieve an increase of 66.8% in the amount of received power when compared to the performance of a conventional beam-forming array. We also demonstrate the efficiency improvement by powering an LED using the on-axis and off-axis focusing configurations.

In order to reduce the cost of the produced electricity, the Linear Fresnel Collector (LFC) system is a promising Concentrated Solar Power (CSP) technology. In this paper a detailed study is conducted aimed at the assessment of the heat losses from the receiver of a real 1 MWe pilot plant based on the Fresnel collector and cooled with a thermal oil. The receiver unit, which consists of an absorber tube and a compound parabolic concentrator (CPC), is investigated numerically in order to determine the receiver performance in different wind directions. Two receiver configurations are analyzed: a simply encapsulated one and an evacuated one. In the latter case, high vacuum conditions are reached in the gap between the absorber tube and the glass cover, whereas in the former case, air at ambient pressure fills the gap. The spatial distribution of the heat flux absorbed by the absorber tube and by the glass cover is determined by means of an optical analysis, conducted with the Monte Carlo based open-source ray-tracing tool Tonatiuh, and it is the driver of the ensuing thermal fluid dynamic analysis. A reference operation condition is studied in detail by means of a 1D model that solves the energy balance for the coolant along the entire length of the receiver. The characterization of the 1D model requires an accurate, multi-dimensional computational fluid dynamic (CFD) analysis, based on the commercial STAR-CCM+ code, which aims at determining the useful heat transferred to the coolant and the convective and radiative heat losses as a function of the oil temperature. A 2D CFD model is used to simulate the thermal behavior of the receiver at different locations along its axis in case of no wind or wind blowing across the collector axis. A 3D CFD model is adopted to study the impact of the wind blowing along the collector axis. The external air is considered in the computational domain in both CFD models, to be able to accurately assess the convective share of the heat losses. At the end, the oil temperature profile along the receiver tube, as well as the heat losses and the thermal efficiency trends, are presented and discussed. The 2D model is also exploited to perform an annual analysis, varying the solar flux and the sun position, but considering just a single wind direction. The results of our analysis indicate that the benefit of using an evacuated tube depends on the heat absorbed on the linear receiver, which depends in turn on the solar flux and on the sun position. The annual-based performance improvement obtained using an evacuated tube is not dramatic, due to the relatively low temperatures of the receiver. Moreover, this analysis also concludes that the receiver performance is only slightly affected by the wind direction and intensity up to ∼ 4 m/s, due to the presence of the CPC that protects the receiver from the external air stream. © 2018 Elsevier Ltd

[EN] In this work, the distortion of the Fresnel Zone Plate focusing profile generated by a piston emitter in ultrasound applications is significantly reduced through the use of phase correction rings, which compensate the effect of the piston emitter radiation diagram. Both simulation and experimental results demonstrate the improvement achieved with this design method over the conventional case., This work has been supported by Spanish MINECO (TEC2015-70939-R).

A unique Fresnel prototype is currently running in France. It is composed of a 1000 m 2 solar field, a thermocline thermal storage and an Organic Rankine Cycle (ORC). This CSP plant is perfectly suited to test the three main parts of a solar power plant (ie. solar field, storage and turbine). More than two years of experience is achieved and the paper aims at presenting some results about this operating period. It shows that this kind of technology is very versatile. Automation experiences along with thermocline behavior are discussed. Electricity production using the storage capacity is also presented. This experimental tool will be upgraded with water chilled production and desalination. The perspective is the optimization of the whole system for MW scale installations.

SPIE OPTO, 2017, San Francisco, California, United States, Giichi Shibuya, Shohei Yamano, Hiroyuki Yoshida, and Masanori Ozaki "Active liquid-crystal deflector and lens with Fresnel structure", Proc. SPIE 10125, Emerging Liquid Crystal Technologies XII, 101250V (15 February 2017). DOI: https://doi.org/10.1117/12.2261113, A new type of tunable Fresnel deflector and lens composed of liquid crystal was developed. Combined structure of multiple interdigitated electrodes and the high-resistivity (HR) layer implements the saw-tooth distribution of electrical potential with only the planar surfaces of the transparent substrates. According to the numerical calculation and design, experimental devices were manufactured with the liquid crystal (LC) material sealed into the sandwiched flat glass plates of 0.7 mm thickness with rubbed alignment layers set to an anti-parallel configuration. Fabricated beam deflector with no moving parts shows the maximum tilt angle of ±1.3 deg which can apply for optical image stabilizer (OIS) of micro camera. We also discussed and verified their lens characteristics to be extended more advanced applications. Transparent interdigitated electrodes were concentrically aligned on the lens aperture with the insulator gaps under their boundary area. The diameter of the lens aperture was 30 mm and the total number of Fresnel zone was 100. Phase retardation of the beam wavefront irradiated from the LC lens device can be evaluated by polarizing microscope images with a monochromatic filter. Radial positions of each observed fringe are plotted and fitted with 2nd degree polynomial approximation. The number of appeared fringes is over 600 in whole lens aperture area and the correlation coefficients of all approximations are over 0.993 that seems enough ideal optical wavefront. The obtained maximum lens powers from the approximations are about ±4 m-1 which was satisfied both convex and concave lens characteristics; and their practical use for the tunable lens grade eyeglasses became more prospective.

Fresnel mirror in thermodynamic solar power plant technology is an efficient power resource in many potential countries. The key challenge is cost effectiveness of the product and its settling. The importance of using this tech- nology redounded in writing this paper to propose a methodology in order to design this system considering its complexities. Because of the dependency of the product with process of production and installation of this solar plant, a simultaneous design methodology is required. Moreover, a concept of movable factory, from one solar farm site to another one, is also discussed which is iden- tified as a proper solution for such project with reusability.