scholarly journals Detecting Damage in Composites

1998 ◽  
Vol 120 (06) ◽  
pp. 76-77
Author(s):  
Anand Asundi
Keyword(s):  
Optical Fiber ◽  
Composite Laminates ◽  
Structural Integrity ◽  
Polarized Light ◽  
Single Mode ◽  
Quarter Wave Plate ◽  
Objective Lens ◽  
Circularly Polarized Light ◽  
Linearly Polarized ◽  
Polarization Maintaining

Research shows that polarimetric optical-fiber sensors embedded in composite laminates can monitor structural integrity and detect damage while the structure remains in service. An experimental arrangement can be created to monitor strain in composite specimens. Light from a linearly polarized helium-neon laser is converted into circularly polarized light using a quarter-wave plate, and is coupled into a polarization-maintaining optical fiber with a microscope objective lens and three-axis positioner. In order to ensure that the intensity modulation was a maximum, the input beam was polarized at 45 degrees to the axes of the fiber. Although this study used polarization-maintaining fibers, similar results also have been seen for standard single-mode fibers.

scholarly journals Waveguide magnetoplasmonic structure based on ferrite garnet film

2018 ◽  
Vol 185 ◽  
pp. 02013 ◽  
Author(s):  
Georgy Basiladze ◽  
Aleksandr Dolgov ◽  
Vladimir Berzhansky ◽  
Andrey Karavainikov ◽  
Anatoly Prokopov
Keyword(s):  
Light Intensity ◽  
Optical Fiber ◽  
Optical Waveguide ◽  
Insertion Loss ◽  
Plasmon Resonance ◽  
Polarized Light ◽  
Single Mode ◽  
Garnet Film ◽  
Ferrite Garnet ◽  
Linearly Polarized

The magnetoplasmonic structure, which is a planar multimode magnetooptical waveguide, 10 μm thick with plasmon resonance SiO2 / Cu coating on the surface is experimentally realized. With the total length of the magnetooptical waveguide 4.6 mm and the length of the SiO2 / Cu coating equal to 3.9 mm, the insertion loss of the structure for TM- and TE-polarized light was 22 and 4 dB, respectively, at a wavelength of 1550 nm. Linearly polarized light was launched into the magneto-optical waveguide using a SMF-28 single-mode optical fiber coupled to the polished input edge of the waveguide. The structure is of interest for use as miniature magnetically controlled modulators of light intensity.

scholarly journals Sharp focus of a circularly polarized optical vortex at the output of a metalens illuminated by linearly polarized light

2019 ◽  
Vol 43 (4) ◽  
pp. 528-534
Author(s):  
A.G. Nalimov ◽  
V.V. Kotlyar
Keyword(s):  
Silicon Film ◽  
Polarized Light ◽  
Optical Vortex ◽  
Quarter Wave Plate ◽  
Phase Plate ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Subwavelength Gratings ◽  
Linearly Polarized ◽  
Quarter Wave

A three-level spiral metalens in an amorphous silicon film is designed. The metalens relief consists of two subwavelength gratings with a 220-nm period (for 633 nm wavelength) and depths of 90 and 170 nm. The metalens forms a left-hand circular polarized optical vortex with topological charge 2 when illuminated by a linearly polarized plane wave. The intensity distribution at a distance of 633 nm is in the form of a subwavelength circle, whereas the longitudinal projection of the Pointing vector has negative values on the optical axis, meaning that a backward energy flow occurs. Two subwavelength gratings with different depth act as quarter-wave plates, transforming linearly polarized light into circularly polarized light with a phase delay of (lambda)/2. This metalens combines functionalities of three optical elements: a quarter-wave plate, a spiral phase plate, and a high-NA diffraction metalens (NA close to unity).

Refractive index and temperature sensing characteristics of an optical fiber sensor based on a tapered single mode fiber/polarization maintaining fiber

2016 ◽  
Vol 14 (5) ◽  
pp. 050604-50608
Author(s):  
Zaihang Yang Zaihang Yang ◽  
Hao Sun Hao Sun ◽  
Tingting Gang Tingting Gang ◽  
Nan Liu Nan Liu ◽  
Jiacheng Li Jiacheng Li ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Temperature Sensing ◽  
Fiber Sensor ◽  
Polarization Maintaining Fiber ◽  
Polarization Maintaining ◽  
Sensing Characteristics

scholarly journals Patterns and properties of polarized light in air and water

2011 ◽  
Vol 366 (1565) ◽  
pp. 619-626 ◽  
Author(s):  
Thomas W. Cronin ◽  
Justin Marshall
Keyword(s):  
Polarized Light ◽  
Natural Scenes ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Current State ◽  
Visual Systems ◽  
The Earth ◽  
Predictable Pattern ◽  
Linearly Polarized ◽  
Polarization Of Light

Natural sources of light are at best weakly polarized, but polarization of light is common in natural scenes in the atmosphere, on the surface of the Earth, and underwater. We review the current state of knowledge concerning how polarization and polarization patterns are formed in nature, emphasizing linearly polarized light. Scattering of sunlight or moonlight in the sky often forms a strongly polarized, stable and predictable pattern used by many animals for orientation and navigation throughout the day, at twilight, and on moonlit nights. By contrast, polarization of light in water, while visible in most directions of view, is generally much weaker. In air, the surfaces of natural objects often reflect partially polarized light, but such reflections are rarer underwater, and multiple-path scattering degrades such polarization within metres. Because polarization in both air and water is produced by scattering, visibility through such media can be enhanced using straightforward polarization-based methods of image recovery, and some living visual systems may use similar methods to improve vision in haze or underwater. Although circularly polarized light is rare in nature, it is produced by the surfaces of some animals, where it may be used in specialized systems of communication.

Laser manipulation in liquid crystals: an approach to microfluidics and micromachines

2006 ◽  
Vol 364 (1847) ◽  
pp. 2789-2805 ◽  
Author(s):  
Helen F Gleeson ◽  
Tiffany A Wood ◽  
Mark Dickinson
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Three Dimensions ◽  
Laser Tweezers ◽  
Fluid Medium ◽  
Circularly Polarized Light ◽  
Viscosity Coefficients ◽  
Linearly Polarized ◽  
Local Shear

Laser trapping of particles in three dimensions can occur as a result of the refraction of strongly focused light through micrometre-sized particles. The use of this effect to produce laser tweezers is extremely common in fields such as biology, but it is only relatively recently that the technique has been applied to liquid crystals (LCs). The possibilities are exciting: droplets of LCs can be trapped, moved and rotated in an isotropic fluid medium, or both particles and defects can be trapped and manipulated within a liquid crystalline medium. This paper considers both the possibilities. The mechanism of transfer of optical angular momentum from circularly polarized light to small droplets of nematic LCs is described. Further, it is shown that droplets of chiral LCs can be made to rotate when illuminated with linearly polarized light and possible mechanisms are discussed. The trapping and manipulation of micrometre-sized particles in an aligned LC medium is used to provide a measure of local shear viscosity coefficients and a unique test of theory at low Ericksen number in LCs.

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