ROTATIONAL PROPERTIES OF MICRO-SLABS DRIVEN BY LINEARLY-POLARIZED LIGHT

2005 ◽  
Vol 14 (03) ◽  
pp. 375-382 ◽  
Author(s):  
CHIH-LANG LIN ◽  
IRÈNE WANG ◽  
MARC PIERRE ◽  
ISABELLE COLOMBIER ◽  
CHANTAL ANDRAUD ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Polarized Light ◽  
Polarization Plane ◽  
Light Polarization ◽  
Good Prediction ◽  
Polarization Anisotropy ◽  
Two Photon ◽  
Flat Slabs ◽  
Linearly Polarized ◽  
Optical Torque

We study the rotational motion of objects trapped in a focused laser beam (optical tweezers). Micrometer-sized flat slabs are fabricated using two-photon photopolymerization. These objects, trapped by linearly-polarized light, tend to align parallel to the polarization plane. This alignment effect is attributed to the polarization anisotropy resulting from the object shape and we present a simple electromagnetic approach to estimate the resulting optical torque. Micro-rotors of different sizes are studied experimentally. We characterize the behavior of micro-objects when the light polarization is rotated at constant speed. Our theoretical approach gives a good prediction of how the size of micro-objects affects their rotation efficiency.

scholarly journals Constraints on Lorentz Invariance Violation with Multiwavelength Polarized Astrophysical Sources

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 44
Author(s):  
Qi-Qi Zhou ◽  
Shuang-Xi Yi ◽  
Jun-Jie Wei ◽  
Xue-Feng Wu
Keyword(s):  
Gamma Ray ◽  
Lorentz Invariance ◽  
Polarized Light ◽  
Polarization Plane ◽  
Polarization Angle ◽  
Intrinsic Polarization ◽  
Frequency Dependent ◽  
Invariance Violation ◽  
Linearly Polarized ◽  
Order Of Magnitude

Possible violations of Lorentz invariance (LIV) can produce vacuum birefringence, which results in a frequency-dependent rotation of the polarization plane of linearly polarized light from distant sources. In this paper, we try to search for a frequency-dependent change of the linear polarization angle arising from vacuum birefringence in the spectropolarimetric data of astrophysical sources. We collect five blazars with multiwavelength polarization measurements in different optical bands (UBVRI). Taking into account the observed polarization angle contributions from both the intrinsic polarization angle and the rotation angle induced by LIV, and assuming that the intrinsic polarization angle is an unknown constant, we obtain new constraints on LIV by directly fitting the multiwavelength polarimetric data of the five blazars. Here, we show that the birefringence parameter η quantifying the broken degree of Lorentz invariance is limited to be in the range of −9.63×10−8<η<6.55×10−6 at the 2σ confidence level, which is as good as or represents one order of magnitude improvement over the results previously obtained from ultraviolet/optical polarization observations. Much stronger limits can be obtained by future multiwavelength observations in the gamma-ray energy band.

Turbidity and the Polarized Light Orientation of the Crustacean Mysidium

1958 ◽  
Vol 35 (3) ◽  
pp. 487-493 ◽  
Author(s):  
RICHARD BAINBRIDGE ◽  
TALBOT H. WATERMAN
Keyword(s):  
Sea Water ◽  
Polarized Light ◽  
Polarization Plane ◽  
Careful Consideration ◽  
Light Illumination ◽  
Turbid Water ◽  
Significant Preference ◽  
Directional Orientation ◽  
Linearly Polarized ◽  
Vertical Beam

1. The influence of the turbidity of the medium on the previously reported directional orientation of the littoral mysid, Mysidium gracile, swimming in a vertical beam of linearly polarized light, has been studied. 2. In carefully clarified sea water the slight preference shown for orientation perpendicular to the polarization plane was not statistically significant. 3. In water made turbid with known amounts of suspended yeast a statistically significant preference for swimming perpendicular to the plane of polarization appeared. 4. This response to the pattern of plarized light illumination appears strontger in highly turbid water than it is in water of moderate turbidity. 5. The mechanism of the observed response seems largely depedent upon discrimination of intensity differences in the light scattered horizontally. 6. These results emphasize the need for careful consideration of the scattering and reflexion artifacts almost invariably present with linearly polarized light.

Two-Photon Fluorescence Polarization Anisotropy Decay on Highly Diluted Solutions by Phase Fluorometry

2001 ◽  
Vol 55 (3) ◽  
pp. 311-317 ◽  
Author(s):  
Francesca Olivini ◽  
Sabrina Beretta ◽  
Giuseppe Chirico
Keyword(s):  
Fluorescence Polarization ◽  
Light Polarization ◽  
Correlation Spectroscopy ◽  
Polarization Anisotropy ◽  
Two Photon ◽  
Protein Size ◽  
High Dilutions ◽  
Fluorescence Polarization Anisotropy ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence

We report here the phase-sensitive measurements of two-photon fluorescence polarization anisotropy (FPA) on highly diluted solutions. We first describe the characterization of the response of the two-photon microscope to the light polarization and its test by means of measurements of the FPA on rhodamine 6G as a function of the viscosity. Further, we report the study of the FPA at high dilutions on a globular protein, the beta-lactoglobulin B (BLG) labeled with Alexa 532. The number of molecules (from 0.4 to 17 molecules per excitation volume) is measured by means of fluorescence correlation spectroscopy (FCS). The average rotational and translational diffusion coefficients measured with the FPA and FCS methods are in good agreement with the protein size and do not show a substantial dependence on the protein concentration, despite the very low signal (≌3 times the background) observed for highly diluted solutions.

scholarly journals Research on beam bunching and deflection characteristics of low-power laser under the electromagnetic effect

2019 ◽  
Vol 52 (5-6) ◽  
pp. 379-386
Author(s):  
Chi Zhang ◽  
Yonghua Lu ◽  
Jing Li ◽  
Rui Wang
Keyword(s):  
Experimental Data ◽  
Low Power ◽  
Polarized Light ◽  
Polarization Plane ◽  
Least Square ◽  
Small Range ◽  
Power Laser ◽  
Coil Current ◽  
Optical Elements ◽  
Linearly Polarized

The bunching and deflection characteristics of low-power laser beam were investigated under electromagnetic field. On the basis of the Faraday effect, the cylindrical electromagnetic cavity was designed and implemented in the experiments. Several types of the magneto-optical elements were placed in the electromagnetic cavity individually. In the test of the deflection characteristics of low-power laser, the rotating angle, the polarization plane of linearly polarized light which passed through electromagnetic cavity, was measured by polarization extinction. We focus on the relation between the coil current and the rotating angle. The experimental data show that when the coil current varies in the range of 0–5 A, the rotating angles changed from 0° to 24.1°. Then, a fitting formula about the coil current and the rotating angle was obtained from the experimental data using the least square algorithm. The analysis shows that the rotating angle is proportional to the excitation current and the correlation coefficient is more than 0.9995. In order to study the beam bunching characteristics of low-power laser, the area of the laser facula was measured after the low-power laser passed through the electromagnetic cavity. The experiment data show that the laser facula area changes in a small range and the experimental data meet 3σ criteria.

scholarly journals Manipulating Weyl quasiparticles by orbital-selective photoexcitation in WTe2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Meng-Xue Guan ◽  
En Wang ◽  
Pei-Wei You ◽  
Jia-Tao Sun ◽  
Sheng Meng
Keyword(s):  
Quantum Dynamics ◽  
Near Infrared ◽  
Coherent Control ◽  
Polarized Light ◽  
Light Polarization ◽  
Effective Electron ◽  
Structural And Electronic Properties ◽  
Linearly Polarized ◽  
Shear Motion ◽  
New Perspective

AbstractOptical control of structural and electronic properties of Weyl semimetals allows development of switchable and dissipationless topological devices at the ultrafast scale. An unexpected orbital-selective photoexcitation in type-II Weyl material WTe2 is reported under linearly polarized light (LPL), inducing striking transitions among several topologically-distinct phases mediated by effective electron-phonon couplings. The symmetry features of atomic orbitals comprising the Weyl bands result in asymmetric electronic transitions near the Weyl points, and in turn a switchable interlayer shear motion with respect to linear light polarization, when a near-infrared laser pulse is applied. Consequently, not only annihilation of Weyl quasiparticle pairs, but also increasing separation of Weyl points can be achieved, complementing existing experimental observations. In this work, we provide a new perspective on manipulating the Weyl node singularity and coherent control of electron and lattice quantum dynamics simultaneously.

scholarly journals On the Extraction of Time Information From Energy-Resolved Experiments

1983 ◽  
Vol 3 (1-6) ◽  
pp. 85-96
Author(s):  
Jean Durup
Keyword(s):  
Cross Section ◽  
Polarized Light ◽  
Partial Cross Section ◽  
Excitation Wavelength ◽  
Time Resolved ◽  
Molecular Systems ◽  
Two Photon ◽  
Photon Excitation ◽  
First Case ◽  
Linearly Polarized

It is well known that in principle energy-resolved and time-resolved experiments provide complementary information. A few examples are reviewed where the time evolution of rapidly relaxing molecular systems is or could be better studied by energy-resolved experiments: (1) the evolution of a pair of resonances coupled with each other through a set of continua, (2) an irreversible relaxation of the intermediate state in the two-photon excitation of a polyatomic molecule, and (3) the derivation of a “dissociation time” from the angular distribution of fragments from photodissociation by linearly polarized light. In the first case it is shown how all parameters necessary for a time-dependent description may be obtained from the measurement, as functions of the excitation wavelength, of both the total absorption cross section across the resonances and the partial cross section for a single exit channel. In the last two cases the relevance of a description in terms of an “eigentime” of the molecule is demonstrated.

scholarly journals A Tunable Graphene 0–90° Polarization Rotator Achieved by Sine Equation Voltage Adjustment

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 849 ◽  
Author(s):  
Jinsong Dai ◽  
Zhongchao Wei ◽  
Lin Zhao ◽  
Qiyuan Lin ◽  
Yuyao Lou
Keyword(s):  
Fermi Level ◽  
Polarized Light ◽  
Light Polarization ◽  
Polarization Angle ◽  
Polarization Rotator ◽  
Terahertz Region ◽  
Linearly Polarized ◽  
Optic Communication ◽  
Radially Polarized ◽  
Sine Equation

Polarization Manipulation has been widely used and plays a key role in wave propagation and information processing. Here, we introduce a polarization rotator in the terahertz range with a polarization conversion ratio up to 99.98% at 4.51 terahertz. It has a single graphene layer on top of the structure patterned by 45° tilted space elliptical rings. By changing the Fermi level from 0.3 ev to 0.7 ev of the graphene, we can turn the reflective light polarization direction between 0° to 90° with nearly unique magnitude. Surface currents theories and graphene characteristics clarify the relationship between polarization angle and Fermi level to be a sine equation adjusted voltage. We firstly put forward an equation to thetunable graphene changing the reflective light polarization angle. It can be widely used in measurement, optic communication, and biology. Besides, with nearly the unique reflective light in different directions, the rotator is designed into a novel radially polarization converter. The latter can be switched from radially polarized light to linearly polarized light, and vice versa, in the terahertz region.

scholarly journals Polarization-Sensitive Light Sensors Based on a Bulk Perovskite MAPbBr3 Single Crystal

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1238
Author(s):  
Yuan Wang ◽  
Laipan Zhu ◽  
Cuifeng Du
Keyword(s):  
Single Crystal ◽  
Polarized Light ◽  
Light Polarization ◽  
Polarization Sensitivity ◽  
Anisotropy Ratio ◽  
Spin Orbit Coupling ◽  
Band Tail ◽  
Linearly Polarized ◽  
Halide Perovskites ◽  
Shed Light

Organic-inorganic halide perovskites have attracted much attention thanks to their excellent optoelectronic performances. Here, a bulk CH3NH3PbBr3 (MAPbBr3) single crystal (SC) was fabricated, whose temperature and light polarization dependence was investigated by measuring photoluminescence. The presence of obvious band tail states was unveiled when the applied temperature was reduced from room temperature to 78 K. Temperature dependence of the bandgap of the MAPbBr3 SC was found to be abnormal compared with those of traditional semiconductors due to the presence of instabilization of out-of-phase tail states. The MAPbBr3 SC revealed an anisotropy light absorption for linearly polarized light with an anisotropy ratio of 1.45, and a circular dichroism ratio of up to 9% was discovered due to the spin-orbit coupling in the band tail states, exhibiting great polarization sensitivity of the MAPbBr3 SC for the application of light sensors. These key findings shed light on the development of potential optoelectronic and spintronic applications based on large-scaled organic-inorganic perovskite SCs.

scholarly journals Orientation of flat particles in optical tweezers by linearly polarized light

2003 ◽  
Vol 11 (5) ◽  
pp. 446 ◽  
Author(s):  
Peter Galajda ◽  
Pal Ormos
Keyword(s):  
Optical Tweezers ◽  
Polarized Light ◽  
Linearly Polarized
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