scholarly journals Tumbling and anomalous alignment of optically levitated anisotropic microparticles in chiral hollow-core photonic crystal fiber

2021 ◽  
Vol 7 (28) ◽  
pp. eabf6053
Author(s):  
Shangran Xie ◽  
Abhinav Sharma ◽  
Maria Romodina ◽  
Nicolas Y. Joly ◽  
Philip St. J. Russell
Keyword(s):  
Electric Field ◽  
Degrees Of Freedom ◽  
Optical Axis ◽  
Polarized Light ◽  
Fiber Axis ◽  
Hollow Core ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Laser Alignment ◽  
Tumbling Motion

The complex tumbling motion of spinning nonspherical objects is a topic of enduring interest, both in popular culture and in advanced scientific research. Here, we report all-optical control of the spin, precession, and nutation of vaterite microparticles levitated by counterpropagating circularly polarized laser beams guided in chiral hollow-core fiber. The circularly polarized light causes the anisotropic particles to spin about the fiber axis, while, regulated by minimization of free energy, dipole forces tend to align the extraordinary optical axis of positive uniaxial particles into the plane of rotating electric field. The end result is that, accompanied by oscillatory nutation, the optical axis reaches a stable tilt angle with respect to the plane of the electric field. The results reveal new possibilities for manipulating optical alignment through rotational degrees of freedom, with applications in the control of micromotors and microgyroscopes, laser alignment of polyatomic molecules, and study of rotational cell mechanics.

scholarly journals Normal electric field enhanced light-induced polarizations and magnetic detection of valley polarization in silicene

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
N. Shahabi ◽  
A. Phirouznia
Keyword(s):  
Electric Field ◽  
Light Emission ◽  
Polarized Light ◽  
Spin Current ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Normal Electric Field ◽  
Valley Polarization ◽  
Population Imbalance ◽  
Magnetic Detection

Abstract The role of staggered potential on light-induced spin and pseudo-spin polarization has been investigated in silicene. It has been shown that non-equilibrium spin and pseudo-spin polarizations are emerged in silicene sheet by applying an external perpendicular electric field in the presence of circularly polarized light emission. This electric field results in pseudo-spin resolved states very close to the Dirac points therefore could be considered as a pseudomagnetic field. It has been shown that staggered potential induced spin-valley locking and pseudo-spin resolved bands are responsible for the enhancement of the spin and pseudo-spin polarizations. Meanwhile, spin-valley locking suggests a coexistence of both spin and valley polarizations with nearly identical (or at least proportional) population imbalance at low Fermi energies which could be employed for magnetic detection of the valley polarization. It has been shown that spin-valley locking results in the protection of the spin polarizations against the relaxations in elastic scattering regime. In addition, the results indicate that the pseudo-spin current can be generated by the circularly polarized light which could be explained by asymmetric light absorption of the states in k-space.

scholarly journals An orbital energy flow and a spin flow at the tight focus

2021 ◽  
Vol 45 (4) ◽  
pp. 520-524
Author(s):  
S.S. Stafeev
Keyword(s):  
Energy Flow ◽  
Optical Axis ◽  
Polarized Light ◽  
Orbital Energy ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Left Hand ◽  
Left Handed ◽  
Sharp Focus ◽  
Positive Projection

We have shown that a reverse energy flow (negative projection of the Poynting vector onto the optical axis) at the sharp focus of an optical vortex with topological charge 2 and left-hand circular polarization arises because the axial spin flow has a negative projection onto the optical axis and is greater in magnitude than positive projection onto the optical axis of the orbital energy flow (canonical energy flow). Also, using the Richards-Wolf formulas, it is shown that when focusing a left-handed circularly polarized light, in the region of the on-axis reverse energy flow, the light is right-handed circularly polarized.

Electric-field-induced differential scattering of right and left circularly polarized light

1975 ◽  
Vol 345 (1642) ◽  
pp. 365-377 ◽  
Keyword(s):  
Electric Field ◽  
Optical Activity ◽  
Electromagnetic Waves ◽  
Polarized Light ◽  
Static Electric Field ◽  
Circularly Polarized Light ◽  
Active Systems ◽  
Circularly Polarized ◽  
Dipolar Molecules ◽  
The Difference

The differential scattering of right and left circularly polarized light is a manifestation of optical activity. Both naturally optically active systems and fluids in a magnetic field parallel to the direction of propagation exhibit differential scattering. Although there is no electric analogue of Faraday’s effect, a static electric field applied to a fluid perpendicular to the direction of propagation induces a difference in the scattered intensities of right and left circularly polarized light. The difference is linear in the field strength. It is determined by the effect of the field on the polarizabilities producing optical activity and is present in all matter, including monatomic gases. The classical theory of the scattering of electromagnetic waves is used in a formulation of the general theory of light scattering in an electric field. Results are given for some particular symmetries, including spherical, tetrahedral and dipolar molecules, and estimates of the magnitude of the effect are made.

Linear Electrogyration Study on Eu:In2O3 Nanocrystals

2009 ◽  
Vol 1207 ◽  
Author(s):  
Zhaoyong Sun ◽  
Ivan V Kityk ◽  
Jiye Fang
Keyword(s):  
Electric Field ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Circularly Polarized

AbstractColloidal Europium-doped In2O3 nanocrystals were successfully prepared in a noncoordinating solvent using indium (III) and europium (III) acetates as precursors. The concentration of doped europium was varied up to 2.88 at%. Linear electrogyration induced by coherent circularly-polarized light was observed from samples in which europium-doped In2O3 nanocrystals were embedded in photopolymer oligoethracryalte matrices. The result on ˜2.5 at% europium-doped sample shows that the maximal linear electrogyration could reach to ˜12 deg./mm at an electric field of 120V/cm for He-Ne laser.

scholarly journals Efficient Achromatic Broadband Focusing and Polarization Manipulation of a Novel Designed Multifunctional Metasurface Zone Plate

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3436
Author(s):  
Shaobo Ge ◽  
Weiguo Liu ◽  
Xueping Sun ◽  
Jin Zhang ◽  
Pengfei Yang ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Incident Light ◽  
Polarization State ◽  
Resonance Effect ◽  
Optical Design ◽  
Polarized Light ◽  
Simulation Method ◽  
Zone Plate ◽  
Circularly Polarized Light ◽  
Circularly Polarized

In this paper, comprehensively utilizing the diffraction theory and electromagnetic resonance effect is creatively employed to design a multifunctional metasurface zone plate (MMZP) and achieve the control of polarization states, while maintaining a broadband achromatic converging property in a near-IR region. The MMZP consists of several rings with fixed width and varying heights; each ring has a number of nanofins (usually called meta-atoms). The numerical simulation method is used to analyze the intensity distribution and polarization state of the emergent light, and the results show that the designed MMZP can realize the polarization manipulation while keeping the broadband in focus. For a specific design wavelength (0.7μm), the incident light can be converted from left circularly polarized light to right circularly polarized light after passing through the MMZP, and the focusing efficiency reaches above 35%, which is more than twice as much as reported in the literature. Moreover, the achromatic broadband focusing property of the MMZP is independent with the polarization state of the incident light. This approach broadens degrees of freedom in micro-nano optical design, and is expected to find applications in multifunctional focusing devices and polarization imaging.

Differential polarization imaging of sickled cells

1988 ◽  
Vol 46 ◽  
pp. 62-63
Author(s):  
Marcos F. Maestre
Keyword(s):  
Optical Properties ◽  
Theoretical Approach ◽  
Polarized Light ◽  
Polarization Microscopy ◽  
Spectroscopic Techniques ◽  
Polarization Imaging ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Microscopic Scale ◽  
Chiral Structures

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.

Blue Circularly Polarized Luminescent Amorphous Molecules with Single-handed Propeller Chirality Induced by Circularly Polarized Light Irradiation

2021 ◽  
Author(s):  
Zhaoming Zhang ◽  
Takunori Harada ◽  
Adriana Pietropaolo ◽  
Yuting Wang ◽  
Yue Wang ◽  
...  
Keyword(s):  
Polarized Light ◽  
Light Irradiation ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Trigonal Symmetry ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence

Preferred-handed propeller conformation was induced by circularly polarized light irradiation to three amorphous molecules with trigonal symmetry, and the molecules with induced chirality efficiently exhibited blue circularly polarized luminescence. In...

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