scholarly journals Underwater Radiance Distributions Measured with Miniaturized Multispectral Radiance Cameras

2013 ◽  
Vol 30 (1) ◽  
pp. 74-95 ◽  
Author(s):  
David Antoine ◽  
André Morel ◽  
Edouard Leymarie ◽  
Amel Houyou ◽  
Bernard Gentili ◽  
...  
Keyword(s):  
Optical Properties ◽  
Complementary Metal Oxide Semiconductor ◽  
Optical Quality ◽  
Low Noise ◽  
Oxide Semiconductor ◽  
Significant Advance ◽  
Inherent Optical Properties ◽  
Camera Design ◽  
Radiance Distribution

Abstract Miniaturized radiance cameras measuring underwater multispectral radiances in all directions at high-radiometric accuracy (CE600) are presented. The camera design is described, as well as the main steps of its optical and radiometric characterization and calibration. The results show the excellent optical quality of the specifically designed fish-eye objective. They also show the low noise and excellent linearity of the complementary metal oxide semiconductor (CMOS) detector array that is used. Initial results obtained in various oceanic environments demonstrate the potential of this instrument to provide new measurements of the underwater radiance distribution from the sea surface to dimly lit layers at depth. Excellent agreement is obtained between nadir radiances measured with the camera and commercial radiometers. Comparison of the upwelling radiance distributions measured with the CE600 and those obtained with another radiance camera also shows a very close agreement. The CE600 measurements allow all apparent optical properties (AOPs) to be determined from integration of the radiance distributions and inherent optical properties (IOPs) to be determined from inversion of the AOPs. This possibility represents a significant advance for marine optics by tying all optical properties to the radiometric standard and avoiding the deployment of complex instrument packages to collect AOPs and IOPs simultaneously (except when it comes to partitioning IOPs into their component parts).

A Study on Scalability and Variation of CMOS Low Noise Amplifier in Advance CMOS Technology Processes

2016 ◽  
Vol 833 ◽  
pp. 135-139
Author(s):  
Dayang Nur Salmi Dharmiza Awang Salleh ◽  
Rohana Sapawi
Keyword(s):  
Complementary Metal Oxide Semiconductor ◽  
Rf Circuits ◽  
Cmos Technology ◽  
Low Noise ◽  
Low Noise Amplifier ◽  
Oxide Semiconductor ◽  
Technology Scaling ◽  
Wireless Applications ◽  
Noise Amplifier ◽  
Technology Processes

Recent technology requires multistandard Radio Frequency (RF) chips for multipurpose wireless applications. In RF circuits, a low-noise amplifier (LNA) plays the key role in determining the receiver’s performance. With CMOS technology scaling, various designs has been adopted to study circuit’s characteristic and variation. In this paper, we present the results of scalable wideband LNA design based on complementary metal oxide semiconductor (CMOS), with its variance study. The design was fabricated in 180nm, 90nm, 65nm and 40nm CMOS technology.

scholarly journals Measuring and Modeling the Polarized Upwelling Radiance Distribution in Clear and Coastal Waters

2018 ◽  
Vol 8 (12) ◽  
pp. 2683 ◽  
Author(s):  
Arthur Gleason ◽  
Kenneth Voss ◽  
Howard Gordon ◽  
Michael Twardowski ◽  
Jean-François Berthon
Keyword(s):  
Optical Properties ◽  
Absorption Coefficient ◽  
Field Experiments ◽  
Absolute Error ◽  
Mueller Matrix ◽  
Spectral Radiance ◽  
Remote Measurement ◽  
Inherent Optical Properties ◽  
Satellite Sensors ◽  
Radiance Distribution

The upwelling spectral radiance distribution is polarized, and this polarization varies with the optical properties of the water body. Knowledge of the polarized, upwelling, bidirectional radiance distribution function (BRDF) is important for generating consistent, long-term data records for ocean color because the satellite sensors from which the data are derived are sensitive to polarization. In addition, various studies have indicated that measurement of the polarization of the radiance leaving the ocean can used to determine particle characteristics (Tonizzo et al., 2007; Ibrahim et al., 2016; Chami et al., 2001). Models for the unpolarized BRDF (Morel et al., 2002; Lee et al., 2011) have been validated (Voss et al., 2007; Gleason et al., 2012), but variations in the polarization of the upwelling radiance due to the sun angle, viewing geometry, dissolved material, and suspended particles have not been systematically documented. In this work, we simulated the upwelling radiance distribution using a Monte Carlo-based radiative transfer code and measured it using a set of fish-eye cameras with linear polarizing filters. The results of model-data comparisons from three field experiments in clear and turbid coastal conditions showed that the degree of linear polarization (DOLP) of the upwelling light field could be determined by the model with an absolute error of ±0.05 (or 5% when the DOLP was expressed in %). This agreement was achieved even with a fixed scattering Mueller matrix, but did require in situ measurements of the other inherent optical properties, e.g., scattering coefficient, absorption coefficient, etc. This underscores the difficulty that is likely to be encountered using the particle scattering Mueller matrix (as indicated through the remote measurement of the polarized radiance) to provide a signature relating to the properties of marine particles beyond the attenuation/absorption coefficient.

An Inverter-Based Wideband Low-Noise Amplifier in 40 nm Complementary Metal Oxide Semiconductor

2012 ◽  
Vol 51 ◽  
pp. 04DE07 ◽  
Author(s):  
Dayang Nur Salmi Dharmiza ◽  
Mototada Oturu ◽  
Satoru Tanoi ◽  
Hiroyuki Ito ◽  
Noboru Ishihara ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Complementary Metal Oxide Semiconductor ◽  
Low Noise ◽  
Metal Oxide Semiconductor ◽  
Low Noise Amplifier ◽  
Oxide Semiconductor ◽  
Noise Amplifier

Optical Properties of Doped Cd1−xMnxTe

1986 ◽  
Vol 89 ◽  
Author(s):  
Y. Lansari ◽  
N. C. Giles ◽  
J. F. Schetzina ◽  
P. Becia ◽  
D. Kaiser
Keyword(s):  
Optical Properties ◽  
Low Temperature ◽  
Spectral Range ◽  
Room Temperature ◽  
Far Infrared ◽  
Optical Quality ◽  
Structural Quality ◽  
Reflectance Measurements ◽  
Low Temperature Photoluminescence

AbstractThe introduction of phosphorus and arsenic dopants into bulk Cd1−xMnx Te crystals grown by the Bridgman-Stockbarger technique has been studieA-with respect to the resulting optical properties. Samples with a Mn composition in the range 0.10 < x < 0.30, both as-grown and annealed, were investigated. A combination of room temperature transmittance and reflectance measurements over the spectral range from the ultraviolet to the far infrared has been used to gain information concerning the structural quality of the samples. Low temperature photoluminescence measurements (1.6−5 K) were used to determine optical quality and excitonic energies.

scholarly journals A multiport MR-compatible neuroendoscope: spanning the gap between rigid and flexible scopes

2016 ◽  
Vol 41 (3) ◽  
pp. E13 ◽  
Author(s):  
Sunil Manjila ◽  
Margherita Mencattelli ◽  
Benoit Rosa ◽  
Karl Price ◽  
Georgios Fagogenis ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Complementary Metal Oxide Semiconductor ◽  
Colloid Cyst ◽  
Oxide Semiconductor ◽  
Light Emitting ◽  
Rigid Endoscope ◽  
Cadaver Testing ◽  
Minimally Invasive Access ◽  
Clinical Scanner

OBJECTIVE Rigid endoscopes enable minimally invasive access to the ventricular system; however, the operative field is limited to the instrument tip, necessitating rotation of the entire instrument and causing consequent tissue compression while reaching around corners. Although flexible endoscopes offer tip steerability to address this limitation, they are more difficult to control and provide fewer and smaller working channels. A middle ground between these instruments—a rigid endoscope that possesses multiple instrument ports (for example, one at the tip and one on the side)—is proposed in this article, and a prototype device is evaluated in the context of a third ventricular colloid cyst resection combined with septostomy. METHODS A prototype neuroendoscope was designed and fabricated to include 2 optical ports, one located at the instrument tip and one located laterally. Each optical port includes its own complementary metal-oxide semiconductor (CMOS) chip camera, light-emitting diode (LED) illumination, and working channels. The tip port incorporates a clear silicone optical window that provides 2 additional features. First, for enhanced safety during tool insertion, instruments can be initially seen inside the window before they extend from the scope tip. Second, the compliant tip can be pressed against tissue to enable visualization even in a blood-filled field. These capabilities were tested in fresh porcine brains. The image quality of the multiport endoscope was evaluated using test targets positioned at clinically relevant distances from each imaging port, comparing it with those of clinical rigid and flexible neuroendoscopes. Human cadaver testing was used to demonstrate third ventricular colloid cyst phantom resection through the tip port and a septostomy performed through the lateral port. To extend its utility in the treatment of periventricular tumors using MR-guided laser therapy, the device was designed to be MR compatible. Its functionality and compatibility inside a 3-T clinical scanner were also tested in a brain from a freshly euthanized female pig. RESULTS Testing in porcine brains confirmed the multiport endoscope's ability to visualize tissue in a blood-filled field and to operate inside a 3-T MRI scanner. Cadaver testing confirmed the device's utility in operating through both of its ports and performing combined third ventricular colloid cyst resection and septostomy with an endoscope rotation of less than 5°. CONCLUSIONS The proposed design provides freedom in selecting both the number and orientation of imaging and instrument ports, which can be customized for each ventricular pathological entity. The lightweight, easily manipulated device can provide added steerability while reducing the potential for the serious brain distortion that happens with rigid endoscope navigation. This capability would be particularly valuable in treating hydrocephalus, both primary and secondary (due to tumors, cysts, and so forth). Magnetic resonance compatibility can aid in endoscope-assisted ventricular aqueductal plasty and stenting, the management of multiloculated complex hydrocephalus, and postinflammatory hydrocephalus in which scarring obscures the ventricular anatomy.

scholarly journals On the Relationship between Corneal Biomechanics, Macrostructure and Optical Properties

2021 ◽  
Author(s):  
Francisco J. Ávila ◽  
Laura Remón ◽  
Maria Concepción Marcellán
Keyword(s):  
Optical Properties ◽  
Biomechanical Properties ◽  
Optical Quality ◽  
Optical Transparency ◽  
Optical Aberrations ◽  
Corneal Aberrations ◽  
Scheimpflug Imaging ◽  
The Hierarchical Structure ◽  
The Relationship

Optical properties of the cornea are responsible for correct vision, ultrastructure allows optical transparency and biomechanical properties governs the shape, elasticity or stiffness of the cor-nea affecting ocular integrity and intraocular pressure. Therefore, optical aberrations, corneal transparency, structure and biomechanics play a fundamental role in the optical quality of hu-man vision, ocular health and refractive surgery outcomes. However, the convergence of those properties is not yet reported at macroscopic scale within the hierarchical structure of the cornea. This work explores the relationships between biomechanics, structure and optical properties (corneal aberrations and optical density) at macrostructural level of the cornea through dual Placido-Scheimpflug imaging and air-puff tonometry systems in a healthy young adult popula-tion. Results showed convergence between optical transparency, corneal macrostructure and biomechanics.

scholarly journals III-V nanowires with quantum dots: MBE growth and properties

2021 ◽  
Vol 2015 (1) ◽  
pp. 012124
Author(s):  
R R Reznik ◽  
K P Kotlyar ◽  
V O Gridchin ◽  
I V Ilkiv ◽  
A I Khrebtov ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Optoelectronic Devices ◽  
Optical Quality ◽  
Silicon Substrates ◽  
Single Photons ◽  
Mbe Growth ◽  
Pl Spectrum ◽  
Good Optical Quality

Abstract We demonstrate growth of AlGaAs NWs with GaAs QDs and InP NWs with InAsP QDs on silicon substrates. Results of GaAs QDs optical properties study have shown that these objects are sources of single photons. In case of InP NWs with InAsP QDs, the results showed that ~ 100% of homogeneously oriented NWs were formed with good optical quality of this system on a Si(111). PL spectrum peak near 1.3 μm indicates that such system is promising for optoelectronic devices.

STRUCTURAL AND OPTICAL PROPERTIES OF ZnO SYNTHESIZED BY TEMPERATURE GRADIENT THERMAL OXIDATION

2010 ◽  
Vol 17 (05n06) ◽  
pp. 497-503 ◽  
Author(s):  
F. K. YAM ◽  
S. S. TNEH ◽  
Y.-Q. CHAI ◽  
W. S. LAU ◽  
Z. HASSAN ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Temperature Gradient ◽  
Thermal Oxidation ◽  
Optical Quality ◽  
Annealing Process ◽  
Zno Thin Films ◽  
Structural And Optical Properties ◽  
Fixed Temperature

In this work, a series of polycrystalline ZnO samples have been synthesized from Zn thin films deposited on Si (100) substrates by using thermal oxidation technique. The ZnO thin film samples grown by this technique were then characterized by a variety of structural and optical characterization tools. The results revealed that the use of novel annealing process i.e. the application of temperature gradient in the thermal treatment could enhance the structural and optical quality of the ZnO thin films significantly as compared to the normal annealing process, i.e. a fixed temperature under different durations. Apart from the improvement of structural and optical properties of ZnO thin films, another striking feature of this novel annealing process was the promotion of the growth of ZnO nanostructures.

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