Spin-orbit interaction and quenched orbital angular momentum inV3Si

1975 ◽  
Vol 11 (5) ◽  
pp. 2053-2055 ◽  
Author(s):  
H. K. Fung ◽  
S. J. Williamson ◽  
C. S. Ting ◽  
M. P. Sarachik
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
P. Gregg ◽  
P. Kristensen ◽  
A. Rubano ◽  
S. Golowich ◽  
L. Marrucci ◽  
...  

Abstract Light carries both orbital angular momentum (OAM) and spin angular momentum (SAM), related to wavefront rotation and polarization, respectively. These are usually approximately independent quantities, but they become coupled by light’s spin-orbit interaction (SOI) in certain exotic geometries and at the nanoscale. Here we reveal a manifestation of strong SOI in fibers engineered at the micro-scale and supporting the only known example of propagating light modes with non-integer mean OAM. This enables propagation of a record number (24) of states in a single optical fiber with low cross-talk (purity > 93%), even as tens-of-meters long fibers are bent, twisted or otherwise handled, as fibers are practically deployed. In addition to enabling the investigation of novel SOI effects, these light states represent the first ensemble with which mode count can be potentially arbitrarily scaled to satisfy the exponentially growing demands of high-performance data centers and supercomputers, or telecommunications network nodes.


2021 ◽  
Vol 5 (45) ◽  
pp. 661-666
Author(s):  
E.A. Bibikova ◽  
N.D. Kundikova ◽  
A.A. Shulginov ◽  
N. Al-Wassiti

The spin angular momentum and the extrinsic orbital angular momentum of light are associated with the polarization of light and the light propagation trajectory, respectively. Those momenta are interdependent not only in an inhomogeneous or anisotropic medium but even in free space. This interaction is called the spin-orbit interaction of light. The effects of the spin-orbit interaction of light manifest themselves in a small transverse shift of the beam field longitudinal component from the beam propagation axis in the waist region under the circular polarization sign change. They can be observed both for Gaussian beams and for structured beams. The effects of the spin-orbit interaction of light should be taken into account when nanophotonics devices are created, but the detailed investigation of the effect had not been performed yet due to the low intensity noise image of the beam waist. Precise measurements of the focal waist centerline are needed to determine the transverse shift of the beam field longitudinal component of the asymmetric converging beam's waist under the circular polarization sign change. We propose methods for determining the transverse and longitudinal positions of the beam waist. Computer image processing methods made it possible to obtain the value of the beam waist's transverse position with an accuracy of 0.1 mkm. These methods will allow further testing of the shifts' theoretical predictions, the values of which are the order of 1 mkm. The results obtained can also be used for laser processing of materials by polarized light and precise positioning of the beam's focal spot at a surface.


Author(s):  
J. Nitta

This chapter focuses on the electron spin degree of freedom in semiconductor spintronics. In particular, the electrostatic control of the spin degree of freedom is an advantageous technology over metal-based spintronics. Spin–orbit interaction (SOI), which gives rise to an effective magnetic field. The essence of SOI is that the moving electrons in an electric field feel an effective magnetic field even without any external magnetic field. Rashba spin–orbit interaction is important since the strength is controlled by the gate voltage on top of the semiconductor’s two-dimensional electron gas. By utilizing the effective magnetic field induced by the SOI, spin generation and manipulation are possible by electrostatic ways. The origin of spin-orbit interactions in semiconductors and the electrical generation and manipulation of spins by electrical means are discussed. Long spin coherence is achieved by special spin helix state where both strengths of Rashba and Dresselhaus SOI are equal.


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