High optical harmonics polarization state due to incident field spatial inhomogeneity

2016 ◽  
Author(s):  
A. V. Andreev ◽  
S. Yu. Stremoukhov ◽  
O. A. Shoutova
Keyword(s):  
Polarization State ◽  
Incident Field ◽  
Spatial Inhomogeneity

Full-parallax 3D display using time-multiplexing projection technology

2020 ◽  
Vol 2020 (2) ◽  
pp. 100-1-100-6
Author(s):  
Takuya Omura ◽  
Hayato Watanabe ◽  
Naoto Okaichi ◽  
Hisayuki Sasaki ◽  
Masahiro Kawakita
Keyword(s):  
Incident Light ◽  
Polarization State ◽  
3D Image ◽  
3D Display ◽  
Time Division Multiplexing ◽  
3D Images ◽  
Polarization Gratings ◽  
Light Rays ◽  
Time Division

We enhanced the resolution characteristics of a threedimensional (3D) image using time-division multiplexing methods in a full-parallax multi-view 3D display. A time-division light-ray shifting (TDLS) method is proposed that uses two polarization gratings (PGs). As PG changes the diffraction direction of light rays according to the polarization state of the incident light, this method can shift light rays approximately 7 mm in a diagonal direction by switching the polarization state of incident light and adjusting the distance between the PGs. We verified the effect on the characteristics of 3D images based on the extent of the shift. As a result, the resolution of a 3D image with depth is improved by shifting half a pitch of a multi-view image using the TDLS method, and the resolution of the image displayed near the screen is improved by shifting half a pixel of each viewpoint image with a wobbling method. These methods can easily enhance 3D characteristics with a small number of projectors.

Enforcing Local Power Conservation for Metasurface Design Using Electromagnetic Inversion

2020 ◽  
Author(s):  
Trevor Brown ◽  
Yousef Vahabzadeh ◽  
Christophe Caloz ◽  
Puyan Mojabi
Keyword(s):  
Optimization Procedure ◽  
Incident Field ◽  
Additional Constraint ◽  
Two Dimensional ◽  
Local Power ◽  
Power Conservation ◽  
Cost Functional ◽  
Field Transformation

<pre>A method based on electromagnetic inversion is extended to facilitate the design of passive, lossless, and reciprocal metasurfaces. More specifically, the inversion step is modified to ensure that the field transformation satisfies local power conservation, using available knowledge of the incident field. This paper formulates a novel cost functional to apply this additional constraint, and describes the optimization procedure used to find a solution that satisfies both the user-defined field specifications and local power conservation. Lastly, the method is demonstrated with a two-dimensional (2D) example.</pre>

Entanglement

2017 ◽  
Author(s):  
Richard Healey
Keyword(s):  
Quantum Theory ◽  
Quantum State ◽  
Physical Condition ◽  
Physical System ◽  
Polarization State ◽  
Quantum Systems ◽  
Ghz State ◽  
Mathematical Representation ◽  
Entangled State ◽  
Physical Relation

Often a pair of quantum systems may be represented mathematically (by a vector) in a way each system alone cannot: the mathematical representation of the pair is said to be non-separable: Schrödinger called this feature of quantum theory entanglement. It would reflect a physical relation between a pair of systems only if a system’s mathematical representation were to describe its physical condition. Einstein and colleagues used an entangled state to argue that its quantum state does not completely describe the physical condition of a system to which it is assigned. A single physical system may be assigned a non-separable quantum state, as may a large number of systems, including electrons, photons, and ions. The GHZ state is an example of an entangled polarization state that may be assigned to three photons.

scholarly journals Modelling combustion in spark ignition engines with special emphasis on near wall flame quenching

2020 ◽  
pp. 146808742097290
Author(s):  
CP Ranasinghe ◽  
W Malalasekera
Keyword(s):  
Combustion Rate ◽  
Fractal Theory ◽  
Pressure Rise ◽  
Spark Ignition ◽  
Spatial Inhomogeneity ◽  
Combustion Model ◽  
Spark Ignition Engines ◽  
Flame Acceleration ◽  
Flame Quenching ◽  
Near Wall

A flame front is quenched when approaching a cold wall due to excessive heat loss. Accurate computation of combustion rate in such situations requires accounting for near wall flame quenching. Combustion models, developed without considering wall effects, cannot be used for wall bounded combustion modelling, as it leads to wall flame acceleration problem. In this work, a new model was developed to estimate the near wall combustion rate, accommodating quenching effects. The developed correlation was then applied to predict the combustion in two spark ignition engines in combination with the famous Bray–Moss–Libby (BML) combustion model. BML model normally fails when applied to wall bounded combustion due to flame wall acceleration. Results show that the proposed quenching correlation has significantly improved the performance of BML model in wall bounded combustion. As a second step, in order to further enhance the performance, the BML model was modified with the use of Kolmogorov–Petrovski–Piskunov analysis and fractal theory. In which, a new dynamic formulation is proposed to evaluate the mean flame wrinkling scale, there by accounting for spatial inhomogeneity of turbulence. Results indicate that the combination of the quenching correlation and the modified BML model has been successful in eliminating wall flame acceleration problem, while accurately predicting in-cylinder pressure rise, mass burn rates and heat release rates.

scholarly journals A mode generator and multiplexer at visible wavelength based on all-fiber mode selective coupler

Nanophotonics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 973-981 ◽  
Author(s):  
Han Yao ◽  
Fan Shi ◽  
Zhaoyang Wu ◽  
Xinzhu Xu ◽  
Teng Wang ◽  
...  
Keyword(s):  
Phase Shift ◽  
Intensity Distribution ◽  
Linear Polarization ◽  
Mode Conversion ◽  
Polarization State ◽  
Stimulated Emission ◽  
Wavelength Multiplexing ◽  
Mode Converters ◽  
Fiber Mode ◽  
Vortex Beams

AbstractUsing an all-fiber mode selective coupler (MSC) at the visible band, here we experimentally demonstrate a generating and wavelength multiplexing scheme for the cylindrical vector (CV) and vortex beams (VBs). The proposed MSCs act as efficient mode converters to produce spectrally insensitive high-order modes (HOMs) at the wavelength ranging from 450 to 980 nm, which have broad operation bandwidth (more than 7 nm), high mode conversion efficiency (94%), and purity (98%), and low insert loss (below 0.5 dB). By adjusting the polarization state and the phase shift of linear polarization (LP)11 mode respectively, the donut-shaped CVs and circular-polarization VBs are achieved. The focused intensity distribution of the donut beam on the cross- and axial-sections is monitored by using a confocal system. The all-fiber solution of producing and multiplexing HOMs opens a new route for stimulated emission depletion microscopy applications.

scholarly journals Spatiotemporal Variability of Mesoscale Eddies in the Indonesian Seas

2021 ◽  
Vol 13 (5) ◽  
pp. 1017
Author(s):  
Zhanjiu Hao ◽  
Zhenhua Xu ◽  
Ming Feng ◽  
Qun Li ◽  
Baoshu Yin
Keyword(s):  
World Ocean ◽  
Mesoscale Eddies ◽  
Spatial Inhomogeneity ◽  
Spatiotemporal Variability ◽  
Identification Algorithm ◽  
Mean Flow ◽  
Sulu Sea ◽  
Indonesian Seas ◽  
Highly Nonlinear ◽  
Eddy Generation

Mesoscale eddies are ubiquitous in the world ocean and well researched both globally and regionally, while their properties and distributions across the whole Indonesian Seas are not yet fully understood. This study investigates for the first time the spatiotemporal variations and generation mechanisms of mesoscale eddies across the whole Indonesian Seas. Eddies are detected from altimetry sea level anomalies by an automatic identification algorithm. The Sulu Sea, Sulawesi Sea, Maluku Sea and Banda Sea are the main eddy generation regions. More than 80% of eddies are short-lived with a lifetime below 30 days. The properties of eddies exhibit high spatial inhomogeneity, with the typical amplitudes and radiuses of 2–6 cm and 50–160 km, respectively. The most energetic eddies are observed in the Sulawesi Sea and Seram Sea. Eddies feature different seasonal cycles between anticyclonic and cyclonic eddies in each basin, especially given that the average latitude of the eddy centroid has inverse seasonal variations. About 48% of eddies in the Sulawesi Sea are highly nonlinear, which is the case for less than 30% in the Sulu Sea and Banda Sea. Instability analysis is performed using high-resolution model outputs from Bluelink Reanalysis to assess mechanisms of eddy generation. Barotropic instability of the mean flow dominates eddy generation in the Sulu Sea and Sulawesi Sea, while baroclinic instability is slightly more in the Maluku Sea and Banda Sea.

scholarly journals Mid infrared polarization engineering via sub-wavelength biaxial hyperbolic van der Waals crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saurabh Dixit ◽  
Nihar Ranjan Sahoo ◽  
Abhishek Mall ◽  
Anshuman Kumar
Keyword(s):  
Room Temperature ◽  
Extinction Ratio ◽  
Polarization State ◽  
Van Der Waals ◽  
Photonic Devices ◽  
Mid Infrared ◽  
Precise Control ◽  
Electromagnetic Simulations ◽  
Frequency Regime ◽  
Sub Wavelength

AbstractMid-infrared (IR) spectral region is of immense importance for astronomy, medical diagnosis, security and imaging due to the existence of the vibrational modes of many important molecules in this spectral range. Therefore, there is a particular interest in miniaturization and integration of IR optical components. To this end, 2D van der Waals (vdW) crystals have shown great potential owing to their ease of integration with other optoelectronic platforms and room temperature operation. Recently, 2D vdW crystals of $$\alpha$$ α -$$\hbox {MoO}_{3}$$ MoO 3 and $$\alpha$$ α -$$\hbox {V}_2 \hbox {O}_5$$ V 2 O 5 have been shown to possess the unique phenomenon of natural in-plane biaxial hyperbolicity in the mid-infrared frequency regime at room temperature. Here, we report a unique application of this in-plane hyperbolicity for designing highly efficient, lithography free and extremely subwavelength mid-IR photonic devices for polarization engineering. In particular, we show the possibility of a significant reduction in the device footprint while maintaining an enormous extinction ratio from $$\alpha$$ α -$$\hbox {MoO}_{3}$$ MoO 3 and $$\alpha$$ α -$$\hbox {V}_2$$ V 2 $$\hbox {O}_5$$ O 5 based mid-IR polarizers. Furthermore, we investigate the application of sub-wavelength thin films of these vdW crystals towards engineering the polarization state of incident mid-IR light via precise control of polarization rotation, ellipticity and relative phase. We explain our results using natural in-plane hyperbolic anisotropy of $$\alpha$$ α -$$\hbox {MoO}_{3}$$ MoO 3 and $$\alpha$$ α -$$\hbox {V}_2$$ V 2 $$\hbox {O}_5$$ O 5 via both analytical and full-wave electromagnetic simulations. This work provides a lithography free alternative for miniaturized mid-infrared photonic devices using the hyperbolic anisotropy of $$\alpha$$ α -$$\hbox {MoO}_{3}$$ MoO 3 and $$\alpha$$ α -$$\hbox {V}_2$$ V 2 $$\hbox {O}_5$$ O 5 .

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