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Picometer Detection by Adaptive Holographic Interferometry
Published in Klaus D. Sattler, Fundamentals of PICOSCIENCE, 2013
Helicity of a CNT is defined as the chirality. If a graphene sheet is rolled such that points A and C touch each other, as shown in Figure 35.8, the resulting carbon nanotube is called (m,n) tube. If a tube is rolled to make a→ perpendicular to the tube axis, this tube is called a zigzag CNT. If the vector is parallel to the tube axis, it is called an armchair CNT. Among the various geometrical shapes, m-n=3 times an integer including the armchair-type (n,n) carbon nanotube is metallic with two linear bands crossing at the Fermi level [29].
An Introductory Review of Quantum Mechanics
Published in Ramaswamy Jagannathan, Sameen Ahmed Khan, Quantum Mechanics of Charged Particle Beam Optics, 2019
Ramaswamy Jagannathan, Sameen Ahmed Khan
Helicity gives the component of spin in the direction of the momentum of the particle in units of ℏ2 and has eigenvalues ±1 since ℏˆ2 = I. Note that the helicity operator commutes with the free-particle Dirac Hamiltonian, i.e.,
Transfer of the spin of an electromagnetic wave to an ideal conductor
Published in Journal of Modern Optics, 2022
It seems that the spin of wave can be detected by changing its direction by wave reflection (Figure 1). When reflected from an ideal conductor, according to electrodynamics, the mutual orientation of the spin and momentum, that is, the helicity of the wave or photon, always changes to the opposite helicity. (The helicity of a particle is positive (‘right-handed’) if the direction of its spin is the same as the direction of its motion. It is negative (‘left-handed’) if the directions of spin and motion are opposite. So a standard clock, with its spin vector defined by the rotation of its hands, has left-handed helicity if tossed with its face directed forwards. But note tip of vector E pictures left spiral if the helicity is right-handed, see Figure 1).