Overview Of Current Scatterometer Measurements And The Impact On Optical Systems

1987 ◽  
Author(s):  
John C. Stover
Keyword(s):  
Optical Systems ◽  
The Impact

Diamond-Like Carbon Coating—It'S Application for Polymeric Substrates

1991 ◽  
Vol 239 ◽  
Author(s):  
Fred M. Kimock ◽  
Alex J. Hsieh ◽  
Peter G. Dehmer ◽  
Pearl W. Yip
Keyword(s):  
High Speed ◽  
Protective Coatings ◽  
Ion Beam ◽  
Chemical Exposure ◽  
Optical Systems ◽  
Impact Behavior ◽  
Organic Liquids ◽  
Diamond Like Carbon ◽  
Dlc Coating ◽  
The Impact

ABSTRACTWe report on a recently commercialized Diamond-Like Carbon (DLC) coating that has been deposited on polycarbonate at near room temperature, via a unique ion beam system. Aspects of high speed impact behavior, chemical resistance, abrasion resistance, and thermal stability of the coating are examined. Results of scanning electron microscopy studies indicate that adhesion of the DLC coating is very good; no delamination of the coating was found on ballistically tested specimens. The well-bonded DLC coating did not cause the impact performance of polycarbonate to become brittle. Chemical exposure test results show that the DLC coating is capable of protecting polycarbonate from chemical attack by aggressive organic liquids. These ion beam deposited DLC coatings have considerable potential as protective coatings for optical systems.

scholarly journals Preparation and Characterization of NbxOy Thin Films: A Review

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1246
Author(s):  
Nwanna Charles Emeka ◽  
Patrick Ehi Imoisili ◽  
Tien-Chien Jen
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Deposition Process ◽  
Optical Systems ◽  
Electrochromic Devices ◽  
Comprehensive Properties ◽  
Direct Band ◽  
Film Characteristics ◽  
The Impact

Niobium oxides (NbO, NbO2, Nb2O5), being a versatile material has achieved tremendous popularity to be used in a number of applications because of its outstanding electrical, mechanical, chemical, and magnetic properties. NbxOy films possess a direct band gap within the ranges of 3.2–4.0 eV, with these films having utility in different applications which include; optical systems, stainless steel, ceramics, solar cells, electrochromic devices, capacitor dielectrics, catalysts, sensors, and architectural requirements. With the purpose of fulfilling the requirements of a vast variety of the named applications, thin films having comprehensive properties span described by film composition, morphology, structural properties, and thickness are needed. The theory, alongside the research status of the different fabrication techniques of NbxOy thin films are reported in this work. The impact of fabrication procedures on the thin film characteristics which include; film thickness, surface quality, optical properties, interface properties, film growth, and crystal phase is explored with emphases on the distinct deposition process applied, are also described and discussed.

scholarly journals Metasurface Spiral Focusing Generators with Tunable Orbital Angular Momentum Based on Slab Silicon Nitride Waveguide and Vanadium Dioxide (VO2)

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1864
Author(s):  
Li Chen ◽  
Lin Zhao ◽  
Yuan Hao ◽  
Wenyi Liu ◽  
Yi Wu ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Vanadium Dioxide ◽  
Communication Systems ◽  
High Speed ◽  
Focal Length ◽  
Polarized Light ◽  
Optical Systems ◽  
Gaussian Beams ◽  
The Impact

The metasurface spiral focusing (MSF) generator has gained attention in high-speed optical communications due to its spatial orthogonality. However, previous MSF generators only can generate a single orbital angular momentum (OAM) mode for one polarized light. Here, a MSF generator with tunable OAM is proposed and it has the ability to transform linearly polarized light (LPL), circularly polarized light or Gaussian beams into vortex beams which can carry tunable OAM at near-infrared wavelength by controlling the phase transition of vanadium dioxide (VO2). Utilizing this MSF generator, the beams can be focused on several wavelength-sized rings with efficiency as high as 76%, 32% when VO2 are in the insulating phase and in the metallic phase, respectively. Moreover, we reveal the relationship between the reflective focal length and transmissive focal length, and the latter is 2.3 times of the former. We further demonstrate the impact of Gaussian beams with different waist sizes on MSF generators: the increase in waist size produces the enhancement in spiral focusing efficiency and the decrease in size of focal ring. The MSF generator we proposed will be applicable to a variety of integrated compact optical systems, such as optical communication systems and optical trapping systems.

scholarly journals LEO Object’s Light-Curve Acquisition System and Their Inversion for Attitude Reconstruction

Aerospace ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 4
Author(s):  
Fabrizio Piergentili ◽  
Gaetano Zarcone ◽  
Leonardo Parisi ◽  
Lorenzo Mariani ◽  
Shariar Hadji Hossein ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Space Debris ◽  
Attitude Determination ◽  
Light Curves ◽  
Optical Systems ◽  
Optical Data ◽  
Impact Point ◽  
Space System ◽  
The Impact ◽  
Space Activities

In recent years, the increase in space activities has brought the space debris issue to the top of the list of all space agencies. The fact of there being uncontrolled objects is a problem both for the operational satellites in orbit (avoiding collisions) and for the safety of people on the ground (re-entry objects). Optical systems provide valuable assistance in identifying and monitoring such objects. The Sapienza Space System and Space Surveillance (S5Lab) has been working in this field for years, being able to take advantage of a network of telescopes spread over different continents. This article is focused on the re-entry phase of the object; indeed, the knowledge of the state of the object, in terms of position, velocity, and attitude during the descent, is crucial in order to predict as accurately as possible the impact point on the ground. A procedure to retrieve the light curves of orbiting objects by means of optical data will be shown and a method to obtain the attitude determination from their inversion based on a stochastic optimization (genetic algorithm) will be proposed.

An improved model for estimating the impact of FWM in coherent optical systems

2016 ◽  
Vol 378 ◽  
pp. 22-27 ◽  
Author(s):  
D. Uzunidis ◽  
C. Matrakidis ◽  
A. Stavdas
Keyword(s):  
Optical Systems ◽  
Improved Model ◽  
The Impact

scholarly journals Si metasurface half-wave plates demonstrated on a 12-inch CMOS platform

Nanophotonics ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 149-157 ◽  
Author(s):  
Yuan Dong ◽  
Zhengji Xu ◽  
Nanxi Li ◽  
Jinchao Tong ◽  
Yuan Hsing Fu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Optical Systems ◽  
Optical Components ◽  
Monolithically Integrated ◽  
Half Wave ◽  
Birefringent Crystals ◽  
Polarization Controlling ◽  
The Impact

AbstractHalf-wave plate (HWP) is one of the key polarization controlling devices in optical systems. The conventional HWPs based on birefringent crystals are inherently bulky and difficult to be monolithically integrated with other optical components. In this work, metasurface-based HWPs with high compactness are demonstrated on a 12-inch silicon complementary metal-oxide-semiconductor platform. Three-dimensional finite difference time domain simulation is used to design the nanostructure and investigate the impact of fabrication process variation on the device performance. In addition, the cross- and co-polarization transmittance (Tcross and Tco) of the HWPs located at different wafer locations are characterized experimentally. The peak Tcross and valley Tco values of 0.69 ± 0.053 and 0.032 ± 0.005 are realized at the wavelength around 1.7 μm, respectively. This corresponds to a polarization conversion efficiency of 95.6% ± 0.8%.

scholarly journals Maximum Likelihood Sequence Detection Receivers for Nonlinear Optical Channels

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Gabriel N. Maggio ◽  
Mario R. Hueda ◽  
Oscar E. Agazzi
Keyword(s):  
Maximum Likelihood ◽  
Channel Estimation ◽  
Fiber Optic ◽  
Matched Filter ◽  
Direct Detection ◽  
Polarization Mode Dispersion ◽  
Optical Systems ◽  
Sequence Detection ◽  
Maximum Likelihood Sequence Detection ◽  
The Impact

The space-time whitened matched filter (ST-WMF) maximum likelihood sequence detection (MLSD) architecture has been recently proposed (Maggio et al., 2014). Its objective is reducing implementation complexity in transmissions over nonlinear dispersive channels. The ST-WMF-MLSD receiver (i) drastically reduces the number of states of the Viterbi decoder (VD) and (ii) offers a smooth trade-off between performance and complexity. In this work the ST-WMF-MLSD receiver is investigated in detail. We show that thespace compressionof the nonlinear channel is an instrumental property of the ST-WMF-MLSD which results in a major reduction of the implementation complexity in intensity modulation and direct detection (IM/DD) fiber optic systems. Moreover, we assess the performance of ST-WMF-MLSD in IM/DD optical systems with chromatic dispersion (CD) and polarization mode dispersion (PMD). Numerical results for a 10 Gb/s, 700 km, and IM/DD fiber-optic link with 50 ps differential group delay (DGD) show that the number of states of the VD in ST-WMF-MLSD can be reduced ~4 times compared to an oversampled MLSD. Finally, we analyze the impact of the imperfect channel estimation on the performance of the ST-WMF-MLSD. Our results show that the performance degradation caused by channel estimation inaccuracies is low and similar to that achieved by existing MLSD schemes (~0.2 dB).

scholarly journals Optical-Radiation-Calorimeter Refinement by Virtual-Sensitivity Analysis

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1167 ◽  
Author(s):  
Lancia Hubley ◽  
Jackson Roberts ◽  
Juergen Meyer ◽  
Alicia Moggré ◽  
Steven Marsh
Keyword(s):  
Spatial Resolution ◽  
Optical Radiation ◽  
Environmental Influence ◽  
Absorbed Dose ◽  
Detector System ◽  
Optical Systems ◽  
Novel Approach ◽  
Heat Expansion ◽  
Path Lengths ◽  
The Impact

Digital holographic interferometry (DHI) radiation dosimetry has been proposed as an experimental metrology technique for measuring absorbed radiation doses to water with high spatial resolution via noninvasive optical calorimetry. The process involves digitally recording consecutive interference patterns resulting from variations in the refractive index as a function of the radiation-absorbed dose. Experiments conducted on prototype optical systems revealed the approach to be feasible but strongly dependent on environmental-influence quantities and setup configuration. A virtual dosimeter reflecting the prototype was created in a commercial optical modelling package. A number of virtual phantoms were developed to characterize the performance of the dosimeter under ideal conditions and with simulated disruptions in environmental-influence quantities, such as atmospheric and temperature perturbations as well as mechanical vibrations. Investigations into the error response revealed that slow drifts in atmospheric parameters and heat expansion caused the measured dose to vary between measurements, while atmospheric fluctuations and vibration contributed to system noise, significantly lowering the spatial resolution of the detector system. The impact of these effects was found to be largely mitigated with equalisation of the dosimeter’s reference and object path lengths, and by miniaturising the detector. Equalising path lengths resulted in a reduction of 97.5% and 96.9% in dosimetric error introduced by heat expansion and atmospheric drift, respectively, while miniaturisation of the dosimeter was found to reduce its sensitivity to vibrations and atmospheric turbulence by up to 41.7% and 54.5%, respectively. This work represents a novel approach to optical-detector refinement in which metrics from medical imaging were adapted into software and applied to a a virtual-detector system. This methodology was found to be well-suited for the optimization of a digital holographic interferometer.

scholarly journals The Impact of Optogenetics on Regenerative Medicine

2019 ◽  
Vol 10 (1) ◽  
pp. 173
Author(s):  
Gianrico Spagnuolo ◽  
Fabio Genovese ◽  
Leonzio Fortunato ◽  
Michele Simeone ◽  
Carlo Rengo ◽  
...  
Keyword(s):  
Regenerative Medicine ◽  
Genetic Manipulation ◽  
Neurological Diseases ◽  
Stroke Recovery ◽  
Optical Systems ◽  
Cell Physiology ◽  
Excitable Cells ◽  
Non Invasive ◽  
The Impact ◽  
Signal Coding

Optogenetics is a novel strategic field that combines light (opto-) and genetics (genetic) into applications able to control the activity of excitable cells and neuronal circuits. Using genetic manipulation, optogenetics may induce the coding of photosensitive ion channels on specific neurons: this non-invasive technology combines several approaches that allow users to achieve improved optical control and higher resolution. This technology can be applied to optical systems already present in the clinical-diagnostic field, and it has also excellent effects on biological investigations and on therapeutic strategies. Recently, several biomedical applications of optogenetics have been investigated, such as applications in ophthalmology, in bone repairing, in heart failure recovery, in post-stroke recovery, in tissue engineering, and regenerative medicine (TERM). Nevertheless, the most promising and developed applications of optogenetics are related to dynamic signal coding in cell physiology and neurological diseases. In this review, we will describe the state of the art and future insights on the impact of optogenetics on regenerative medicine.

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