Koehler illumination in high-resolution optical metrology

2006 ◽  
Author(s):  
Yeung Joon Sohn ◽  
Brian M. Barnes ◽  
Lowell Howard ◽  
Richard M. Silver ◽  
Ravikiran Attota ◽  
...  
Keyword(s):  
High Resolution ◽  
Optical Metrology ◽  
Koehler Illumination

Real-time spectral interleaved electro-optic dual-comb spectroscopy

2020 ◽  
Author(s):  
Bingxin Xu ◽  
Xinyu Fan ◽  
Shuai Wang ◽  
Zuyuan He
Keyword(s):  
High Resolution ◽  
Real Time ◽  
Figure Of Merit ◽  
Frequency Comb ◽  
Sampling Rate ◽  
Optical Metrology ◽  
Broad Bandwidth ◽  
Frequency Combs ◽  
Electro Optic ◽  
Spectral Sampling

Abstract Optical frequency comb with evenly spaced lines over a broad bandwidth has revolutionized the fields of optical metrology and spectroscopy. Here, we propose an electro-optic dual-comb spectroscopy to real-time interleave the spectrum with high resolution, in which two electro-optic frequency combs are seed by swept light source. An interleaved spectrum with a high resolution is real-time recorded by the sweeping probe comb without gap time, which is multi-heterodyne detected by the sweeping local comb. The proposed scheme measures a spectrum spanning 304 GHz in 1.6 ms with a resolution of 1 MHz, and reaches a spectral sampling rate of 1.9*108 points/s under Nyquist-limitation. A reflectance spectrum is measured with a calculated figure-of-merit of 4.2*108, which shows great prospect for fast and high-resolution applications.

Piping and Equipment Dynamics of High Rate HVGO Pumps

2020 ◽  
Author(s):  
Alwyn Kaye
Keyword(s):  
High Resolution ◽  
High Speed ◽  
Dimensional Accuracy ◽  
Rate Of Change ◽  
Operating Conditions ◽  
High Rate ◽  
Optical Metrology ◽  
Deformation Analysis ◽  
Digital Imagery ◽  
Tensor Fields

Abstract A set of Heavy Vacuum Gas Oil (HVGO) pumps in a 300 kbbl/day operating Upgrader Plant experienced repeated failures; typically less than 7 weeks. The pumps run continuously in a high-pressure, high temperature and corrosive environment and their functional status directly affects the reliability of the plant. Upon research, an experimental strain measurement technique using very high resolution laser digital imagery and optical metrology was found from military and advanced aerospace applications to verify high level dimensional accuracy of critical components [1]. Application to a complex and operating bitumen upgrader was unknown. The objective of this project was to use advanced optical metrology with digital image processing techniques employing multiple laser and high-speed cameras capable of generating pump and pipe component’s real time strain images, displacement and rate of change. Optical metrology can analyze the mechanical properties and behavior of many materials and in various test scenarios [2]. Hot and cold operating service, with variations in flow and temperature all dynamically affect the strain measurements. Three significant advantages of the optical method are: i. Avoids a host of problems of strain gauge application, wiring and setup. ii. The problems of temperature sensitivity and correction are overcome. [3] iii. Gathers much more extensive data than possible with traditional methods. The vibration characteristics of the pumps and related hardware were analyzed using high resolution laser and photogrammetric digital imagery and digital strain mapping analysis to determine the characteristics that would ensure the long-term reliable and safe operation of the HVGO pumps. The stress and deformation analysis were performed on the operating pumps in a variety of normal (1280 m3/hr.) and upset operating conditions including under partial and full load conditions. Dynamic and modal analysis of the pumps was developed and analyzed. The displacement and tensor fields of the hardware including the pumps, bases and piping were measured using high resolution laser cameras and analyzed. From the high-speed data gathering and loading analysis showed the deformation and stress affecting the pump and related hardware. The key variables undermining reliable performance were revealed and from the data the necessary remedial action was determined. The pumps have operated for over 30months to the time of writing without repeat failure. This paper should be read in conjunction with PVP 2020-21203; Investigation and Resolution of the Fluid Structure Interaction of High Rate HVGO Pumps.

Application of through-focus focus-metric analysis in high resolution optical metrology

2005 ◽  
Author(s):  
Ravikiran Attota ◽  
Richard M. Silver ◽  
Thomas A. Germer ◽  
Michael Bishop ◽  
Robert Larrabee ◽  
...  
Keyword(s):  
High Resolution ◽  
Optical Metrology ◽  
Metric Analysis

High-resolution optical metrology

2005 ◽  
Author(s):  
R. M. Silver ◽  
R. Attota ◽  
M. Stocker ◽  
M. Bishop ◽  
L. Howard ◽  
...  
Keyword(s):  
High Resolution ◽  
Optical Metrology

Molecular Scale Imaging with a Multilayer Superlens

2006 ◽  
Vol 919 ◽  
Author(s):  
Pratik Chaturvedi ◽  
Nicholas X. Fang
Keyword(s):  
High Resolution ◽  
Single Layer ◽  
Diffraction Limit ◽  
Image Resolution ◽  
Optical Metrology ◽  
Optimized Design ◽  
Low Loss ◽  
Molecular Scale ◽  
Illumination Wavelength ◽  
Better Than

AbstractIt has been experimentally demonstrated that a single layer of silver functions as a “superlens” [Fang et al, Science 308, 534 (2005)], providing image resolution much better than the diffraction limit. Resolution as high as 60 nanometer (λ/6) half-pitch was achieved. In this paper, we explore the possibility of further refining the image resolution using a “multilayer superlens” design. With optimized design of silver-alumina multilayer superlens, our numerical simulations show a feasibility of resolving 15nm features, about 1/26th of the illumination wavelength. We present preliminary experimental results targeted towards achieving the molecular scale imaging resolution. The development of potential low-loss and high resolution superlens opens the door to exciting applications in nanoscale optical metrology and nanomanufacturing.

Observations of the spatial structure of interstellar hydrogen

1967 ◽  
Vol 31 ◽  
pp. 45-46
Author(s):  
Carl Heiles
Keyword(s):  
High Resolution ◽  
Spatial Structure ◽  
Velocity Dispersion ◽  
Temperature Variations

High-resolution 21-cm line observations in a region aroundlII= 120°,b11= +15°, have revealed four types of structure in the interstellar hydrogen: a smooth background, large sheets of density 2 atoms cm-3, clouds occurring mostly in groups, and ‘Cloudlets’ of a few solar masses and a few parsecs in size; the velocity dispersion in the Cloudlets is only 1 km/sec. Strong temperature variations in the gas are in evidence.

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