The low-transmittance elements required for a high power laser facility have stringent specifications about transmittance. To validate optic performance against specifications, a metrology system for transmittance is proposed. The system is composed of a laser source, an integrating sphere, a power meter, and four uncoated wedged glasses. A relative measurement method is adopted, which is that the surface reflectivity of uncoated glass is used as the reference to compare with the sample's transmittance. The systematic feature is that uncoated wedged glasses are applied to split and reflect beams, which not only avoid coating errors, but also make the two beam powers attenuate properly. Measurement results for a sample's transmittance are presented. Experiment and analysis show that the relative standard uncertainty (σ(T)/T) of measurement is 0.424%. This system is available for large-aperture elements.
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http://dx.doi.org/10.1364/AO.51.002395 | DOI Listing |
Rev Sci Instrum
December 2022
Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA.
Measurements of laser absorption in high-temperature, underdense plasmas produced at the Omega Laser Facility are made using two near-field imaging detectors that diagnose the spatial profile and energy of the port P9 beam before and after it transmits through the plasma. The incident beam is sampled using a partial reflection from a full-aperture, (30 cm-diam) uncoated wedge pickoff located before the target chamber vacuum window and final focus lens assembly. A concave mirror reduces the reflected beam size, allowing it to be recorded directly using a charged-coupled device (CCD) camera.
View Article and Find Full Text PDFSoft Matter
September 2022
Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA.
Fog harps effectively drain small droplets, which prevents clogging and results in more water harvested from fog compared to mesh nets. However, the dynamics of fog droplets coalescing and sliding down a vertical wire remain poorly understood. Here, we develop an analytical model that captures the physics of fog droplets draining down a single vertical wire.
View Article and Find Full Text PDFJ Food Sci Technol
September 2018
3Fishery Resources Assessment Division (FRAD), ICAR-Central Marine Fisheries Research Institute, Kochi, 682 018 India.
The objective of this study was to monitor overall quality and to extend the shelf life of fresh-cut apple wedges. Fresh-cut apple wedges were treated with anti-browning agents and edible coatings alone as well as in combination and packed in polypropylene trays. Packed apple wedges were stored at 5 ± 2 °C and monitored for physical (colour, physiological loss in weight and firmness), bio-chemical (ascorbic acid, total antioxidant, phenol, polyphenol oxidase and peroxidase enzymes) and microbial quality.
View Article and Find Full Text PDFOpt Lett
November 2012
V.E. Lashkarev's Institute for Physics of Semiconductors, NAS of Ukraine, Kiev, Ukraine.
The efficient electric field enhancement due to coating a dielectric wedge by plasmon-carrying nanowires has been demonstrated numerically within the framework of the finite-difference frequency-domain method. The numerical simulations show increasing of electric field intensity in the near-field region of the dielectric wedge coated by silver nanowires in the regime of local plasmon excitation up to 100 times versus the uncoated case.
View Article and Find Full Text PDFAppl Opt
May 2012
The Advanced Optical Instrument Research Department, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, China.
The low-transmittance elements required for a high power laser facility have stringent specifications about transmittance. To validate optic performance against specifications, a metrology system for transmittance is proposed. The system is composed of a laser source, an integrating sphere, a power meter, and four uncoated wedged glasses.
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