scholarly journals Longitudinal Component Properties of Circularly Polarized Terahertz Vortex Beams

2021 ◽  
Vol 9 ◽  
Author(s):  
Miao Wang ◽  
Xinke Wang ◽  
Peng Han ◽  
Wenfeng Sun ◽  
Shengfei Feng ◽  
...  
Keyword(s):  
Spot Size ◽  
Longitudinal Component ◽  
Transverse Component ◽  
Quarter Wave Plate ◽  
Phase Plate ◽  
Vortex Beam ◽  
Circularly Polarized ◽  
Left Hand ◽  
Quarter Wave ◽  
Focusing Properties

A circularly polarized vortex beam possesses similar focusing properties as a radially polarized beam. This type of beam is highly valuable for developing optical manufacturing technology, microscopy, and particle manipulation. In this work, a left-hand circularly polarized terahertz (THz) vortex beam (CPTVB) is generated by utilizing a THz quarter wave plate and a spiral phase plate. Focusing properties of its longitudinal component Ez are detailedly discussed on the simulation and experiment. With reducing the F-number of the THz beam and comparing with a transverse component Ex of a general circularly polarized THz beam, the simulation results show that the focal spot size and intensity of its Ez component can reach 87 and 50% of Ex under a same focusing condition. In addition, the experimental results still demonstrate that the left-hand CPTVB can always maintain fine Ez focusing properties in a broad bandwidth, which manifest the feasibility of this class of THz beams.

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).

Tunable-wavelength production of circularly polarized X-rays with a perfect-crystal quarter-wave plate

1992 ◽  
Vol 25 (4) ◽  
pp. 531-535 ◽  
Author(s):  
K. Hirano ◽  
K. Kanzaki ◽  
M. Mikami ◽  
M. Miura ◽  
K. Tamasaku ◽  
...  
Keyword(s):  
Perfect Crystal ◽  
Quarter Wave Plate ◽  
X Rays ◽  
Circularly Polarized ◽  
Wave Plate ◽  
Quarter Wave ◽  
Tunable Wavelength

scholarly journals PolarizationPendellösungand the Generation of Circularly Polarized X Rays with a Quarter-Wave Plate

1986 ◽  
Vol 57 (2) ◽  
pp. 202-205 ◽  
Author(s):  
J. A. Golovchenko ◽  
B. M. Kincaid ◽  
R. A. Levesque ◽  
A. E. Meixner ◽  
D. R. Kaplan
Keyword(s):  
Quarter Wave Plate ◽  
X Rays ◽  
Circularly Polarized ◽  
Wave Plate ◽  
Quarter Wave

scholarly journals Inversion of the longitudinal component of spin angular momentum in the focus of a left-handed circularly polarized beam

2020 ◽  
Vol 44 (5) ◽  
pp. 699-706
Author(s):  
A.G. Nalimov ◽  
E.S. Kozlova
Keyword(s):  
Angular Momentum ◽  
Energy Flow ◽  
Longitudinal Component ◽  
Angular Momentum Vector ◽  
Spin Angular Momentum ◽  
Momentum Vector ◽  
Circularly Polarized ◽  
Left Hand ◽  
Left Handed ◽  
Polarized Beam

It has been shown theoretically and numerically that in the sharp focus of a circularly polarized optical vortex, the longitudinal component of the spin angular momentum vector is inverted. Moreover, if the input light to the optical system is left-hand circularly polarized, it has been shown to be right-hand polarized in the focus near the optical axis. Since this effect occurs near the focus where a backward energy flow takes place, such an inversion of the spin angular momentum can be used to detect the backward energy flow.

scholarly journals High-performance bifunctional polarization switch chiral metamaterials by inverse design method

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Chuanbao Liu ◽  
Yang Bai ◽  
Ji Zhou ◽  
Qian Zhao ◽  
Yihao Yang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Design Method ◽  
Inverse Design ◽  
Quarter Wave Plate ◽  
Circularly Polarized ◽  
Chiral Metamaterials ◽  
Polarized Waves ◽  
Linearly Polarized ◽  
Quarter Wave ◽  
Inverse Design Method

Abstract Multifunctional polarization controlling plays an important role in modern photonics, but their designs toward broad bandwidths and high efficiencies are still rather challenging. Here, by applying the inverse design method of model-based theoretical paradigm, we design cascaded chiral metamaterials for different polarization controls in oppositely propagating directions and demonstrate their broadband and high-efficiency performance theoretically and experimentally. Started with the derivation of scattering matrix towards specified polarization control, a chiral metamaterial is designed as a meta-quarter-wave plate for the forward propagating linearly polarized wave, which converts the x- or y-polarized wave into a nearly perfect left- or right-handed circularly polarized wave; intriguingly, it also serves as a 45° polarization rotator for the backward propagating linearly polarized waves. This bifunctional metamaterial shows a high transmission as well as a broad bandwidth due to the Fabry–Perot-like interference effect. Using the similar approach, an abnormal broadband meta-quarter-wave plate is achieved to convert the forward x- and y-polarized or the backward y- and x-polarized waves into left- and right-handed circularly polarized waves with high transmission efficiencies. The integration of multiple functions in a single structure endows the cascaded chiral metamaterials with great interests for the high-efficiency polarization-controlled applications.

scholarly journals Observation of strongly collimated proton beam from Tantalum targets irradiated with circular polarized laser pulses

2006 ◽  
Vol 24 (1) ◽  
pp. 117-123 ◽  
Author(s):  
MASATAKA KADO ◽  
HIROYUKI DAIDO ◽  
ATSUSHI FUKUMI ◽  
ZHONG LI ◽  
SATOSHI ORIMO ◽  
...  
Keyword(s):  
Proton Beam ◽  
Laser Pulses ◽  
High Energy ◽  
Track Detector ◽  
Beam Line ◽  
Quarter Wave Plate ◽  
Circularly Polarized ◽  
High Intensity Laser ◽  
Quarter Wave ◽  
Intensity Laser

High-energy protons are generated by focusing an ultrashort pulsed high intensity laser at the Advanced Photon Research Center, JAERI-Kansai onto thin (thickness <10 μm) Tantalum targets. The laser intensities are about 4 × 1018 W/cm2. The prepulse level of the laser pulse is measured with combination of a PIN photo diode and a cross correlator and is less than 10−6. A quarter-wave plate is installed into the laser beam line to create circularly polarized pulses. Collimated high energy protons are observed with CH coated Tantalum targets irradiated with the circularly polarized laser pulses. The beam divergence of the generated proton beam is measured with a CR-39 track detector and is about 6 mrad.

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