Fringe field-tunable LC refractive index interface for in-plane beam steering applications

2020 ◽  
Vol 59 (34) ◽  
pp. 10695
Author(s):  
Irina I. Rushnova ◽  
Elena A. Melnikova ◽  
Olga S. Kabanova ◽  
Alexei L. Tolstik ◽  
Alexander A. Muravsky
Keyword(s):  
Refractive Index ◽  
Beam Steering ◽  
Fringe Field

scholarly journals Automatic Characterization of the Refractive Index Profile of Fibers by Interferometry

2002 ◽  
Vol os-11 (1) ◽  
pp. 1558925002OS-01
Author(s):  
Han Seong Kim ◽  
Behnam Pourdeyhimi
Keyword(s):  
Refractive Index ◽  
Interference Fringe ◽  
Axial Direction ◽  
Refractive Index Profile ◽  
Path Difference ◽  
Fringe Field ◽  
Index Profile ◽  
Degree Of Orientation ◽  
Non Destructive

Interferometry provides a non-destructive method for examining the refractive index profile or the radial birefringence distribution within fibers. The key step in the interference data reduction involves the extraction of the refractive index profile along the axial direction of the fiber. The profile is due to the path difference between the fiber and the immersion liquid when a fiber is oriented perpendicular to the fringe field in an interference microscope. The refractive index provides a measure of the degree of optical anisotropy and is indicative of the degree of orientation of the structure. This is of particular interest to nonwovens because in thermally bonded nonwovens, the orientation plays a major role in how well the fibers are bonded and the ultimate properties of the fabric. Despite its long history, however, the interpretation of the interference fringe shift is not precisely defined. Consequently, the data are not reproducible from one laboratory to the next. We outline below an objective and quantitative method for precisely measuring a fiber's refractive index profile from a digitized image of the interference fringe. This new algorithm uses the Fast Fourier Transform (FFT) to remove the inherent noise present in the fiber interferogram and to aid in extracting the profile.

Optical Analyses of Microfluidic Tunable Liquid Prisms for Enhanced Solar Energy Collection

2014 ◽  
Author(s):  
Abhishek Wadhwa ◽  
Sung-Yong Park
Keyword(s):  
Refractive Index ◽  
Solar Energy ◽  
Reflection Loss ◽  
High Efficiency ◽  
Material Selection ◽  
Incident Angle ◽  
Tracking System ◽  
Low Cost ◽  
Beam Steering ◽  
Index Ratio

We present optical analyses of a microfluidic tunable liquid prism to find its optimized configuration that can achieve wider beam steering as well as less reflection loss and eventually maximize solar energy capture without mechanical tracking. For this study, four different prism configurations are compared from single to quad-stacked ones with various refractive indices of the liquids filled in the prism. Its beam steering capability can be improved by increasing the refractive index ratio between the liquids used and by using higher number of the stacked prisms. The quad-stacked prism is able to steer incoming sunlight with an incident angle of a α ≤ ± 75° at an apex angle of φ ≤ ± 30°, which represents more than 5 times improvement, when it is compared to the single prism using the same liquids. For appropriate liquid material selection, the effect of refractive index ratio, r = n2/n1, on beam steering was additionally studied. However, one considerable issue is the fact that the better beam steering, the more reflection loss. This is because both higher number of interfaces and larger refractive index ratio make more reflection at each of the interfaces. Our reflectance analysis showed that the quad prism performs inferior to the double prism until α = ± 32°, while being of superior beam steering performance. To further reduce the solar energy loss through the quad prism, a modified configuration is proposed with a thin film added to the interfaces. 50 % of the total reflection was reduced. Our technology promises an alternative to a low-cost and high-efficiency solar tracking system capable of beam steering as wide as ± 75° and reflection loss as low as 4.5%, during all daily tracking of the sun.

scholarly journals High-efficiency, tunable, fringe-field switching-mode beam steering based on a liquid crystal Pancharatnam phase

2020 ◽  
Vol 59 (34) ◽  
pp. 10706
Author(s):  
Comrun Yousefzadeh ◽  
Andre Van Rynbach ◽  
Doug Bryant ◽  
Philip Bos
Keyword(s):  
Liquid Crystal ◽  
High Efficiency ◽  
Beam Steering ◽  
Fringe Field ◽  
Pancharatnam Phase ◽  
Mode Beam ◽  
Switching Mode

scholarly journals A Review of Various Approaches for Beam Steering in Lens Antenna Authors Avinash Saroj

2021 ◽  
Author(s):  
Avinash Saroj ◽  
Nitesh Kashyap
Keyword(s):  
Refractive Index ◽  
Relative Phase ◽  
Beam Steering ◽  
Antenna Element ◽  
Wide Angle ◽  
Lens Antenna ◽  
Lens Antennas ◽  
Radar Systems

In this paper, we will be reviewing beam steering application using lens antenna. Various approaches are available for achieving beam steering of lens antennas for different applications and some of them will be reviewed here. In radar systems, beam steering is accomplished by switching the antenna element or changing the relative phase. Beam steering has major role for 5g due to the quasi optic layer. Beam steering can also be done by varying the refractive index. In most of these papers studies, we found out that beam steering overcomes the interference, improves gain, increases directivity and also save power. Wide angle is also achieved in lens antenna.

scholarly journals Investigation of Kerr effect in a blue phase liquid crystal using wedge-cell technique

2017 ◽  
Vol 9 (2) ◽  
pp. 54 ◽  
Author(s):  
Kamil Orzechowski ◽  
Marek Wojciech Sierakowski ◽  
Marzena Sala-Tefelska ◽  
Tomasz Ryszard Woliński ◽  
Olga Strzeżysz ◽  
...  
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Electric Field ◽  
Kerr Effect ◽  
Beam Steering ◽  
Phase Liquid ◽  
Blue Phase ◽  
Blue Phases ◽  
Polymer Stabilized

In this work an alternative method for refractive index measurement of blue phase liquid crystal in the Kerr effect has been described. The proposed wedge method uses simple goniometric setup, allowing for direct index measurements for any wavelengths and index values. This is significant advantage comparing to other methods, usually having limitations of the measurement range as well as necessity complicated calculation to obtain refractive indices values. The results are reliable and agree well with the subject literature. Full Text: PDF ReferencesW. Cao et al., "Lasing in a three-dimensional photonic crystal of the liquid crystal blue phase II", Nat. Mater. 1, 111-113 (2002). CrossRef S. Meiboom, M. Sammon, W.F. Brinkman, "Lattice of disclinations: The structure of the blue phases of cholesteric liquid crystals", Phys. Rev. A. 27, 438 (1983). CrossRef S. Tanaka et al., "Double-twist cylinders in liquid crystalline cholesteric blue phases observed by transmission electron microscopy", Sci. Rep. 5, 16180 (2015). CrossRef Y. Li and S.-T. Wu, "Polarization independent adaptive microlens with a blue-phase liquid crystal", Opt. Express 19(9), 8045-8050 (2011). CrossRef N. Rong et al., "Polymer-Stabilized Blue-Phase Liquid Crystal Fresnel Lens Cured With Patterned Light Using a Spatial Light Modulator", J. of Disp. Technol. 12(10), 1008-1012 (2016). CrossRef J.-D. Lin et al., "Spatially tunable photonic bandgap of wide spectral range and lasing emission based on a blue phase wedge cell", Opt. Express 22(24), 29479-29492 (2014). CrossRef P. Joshi et al., "Tunable light beam steering device using polymer stabilized blue phase liquid crystals", Photon. Lett. Poland 9(1), 11-13 (2017). CrossRef Ch.-W. Chen et al., "Temperature dependence of refractive index in blue phase liquid crystals", Opt. Mater. Express 3(5), 527-532 (2013). CrossRef Y.-H. Lin et al., "Measuring electric-field-induced birefringence in polymer stabilized blue-phase liquid crystals based on phase shift measurements", J. Appl. Phys. 109, 104503 (2011). CrossRef J. Yan et al., "Direct measurement of electric-field-induced birefringence in a polymer-stabilized blue-phase liquid crystal composite", Opt. Express 18(11), 11450-11455 (2010). CrossRef K.A. Rutkowska, K. Orzechowski, M. Sierakowski, "Wedge-cell technique as a simple and effective method for chromatic dispersion determination of liquid crystals", Photon. Lett. Poland 8(2), 51-53 (2016). CrossRef O. Chojnowska et al., "Electro-optical properties of photochemically stable polymer-stabilized blue-phase material", J. Appl. Phys. 116, 213505 (2014). CrossRef J. Yan et al., "Extended Kerr effect of polymer-stabilized blue-phase liquid crystals", Appl. Phys. Lett. 96, 071105 (2010). CrossRef M. Chen et al., "Electrically assisting crystal growth of blue phase liquid crystals", Opt. Mater. Express 4(5), 953-959 (2014). CrossRef J. Kerr, Philos. Mag. 50, 337 (1875).

Beam steering by using a gradient refractive index metamaterial planar lens and a gradient phase metasurface planar lens

2018 ◽  
Vol 60 (2) ◽  
pp. 330-337 ◽  
Author(s):  
Yahong Liu ◽  
Congcong Liu ◽  
Xueyu Jin ◽  
Beiyi Zhang ◽  
Yinghuai Zhang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Beam Steering ◽  
Planar Lens ◽  
Gradient Refractive Index ◽  
Gradient Phase
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