Sagnac interference in carbon nanotubes

Abstract

The Sagnac interference mode arises when two interfering counterpropogating beams traverse a loop, but with their velocities detuned by a small amount 2u, with v R/L = v F Ϯ u. In this paper we perform a perturbative nonequilibrium calculation of Sagnac interference in single-channel wires as well as armchair nanotube loops. We study the dependence of the Sagnac conductance oscillations on temperature and interactions. We find that the Sagnac interference is not destroyed by strong interactions, but becomes weakly dependent on the velocity detuning u. In armchairs nanotubes with typical interaction strength, 0.25Յ g Յ 0.5, we find that the necessary temperature for observing the interference effect, T SAG is also only weakly dependent on the interaction, and is enhanced by a factor of 8 relative to the temperature necessary for observing Fabry-Pérot interference in the same system, T FP .

Graphene nanoribbons: Photonic crystal waveguide analogy and minigap stripes

“…Model systems of lower dimensionality are a welcome playground in condensed matter and in photonics as well, making timely comparisons 1 instructive for a broader audience. One-dimensional systems exist for a long time in both domains, e.g., polydiacetylene or carbon nanotubes in the former, and optical fibers and channel waveguides in the latter.…”

Spin–Orbital Coupling and Conservation Laws in Electromagnetic Waves Propagating through Chiral Media

“…Meanwhile, a Sagnac interferometer is based on the interference effects arising from two waves with distinct phase speeds. These effects may involve matter, electrons, or photons [27,32]. Interference effects arising from the differential rotations employed by a Sagnac loop [31] bear a resemblance to the counter-rotating pair of a left wave and right wave on a circular basis, as examined in this study and [8].…”

Spin-Orbital Coupling and Conservation Laws in Electromagnetic Waves Propagating through Chiral Media

“…Meanwhile, a Sagnac interferometer is based on the interference effects arising from two waves with distinct phase speeds. These effects may involve matters, electrons, or photons [27], [32]. Interference effects arising from differential rotations employed by a Sagnac loop [31] bear resemblance to a counter-rotating pair of a left wave and right wave on the circular basis as examined in this study.…”

“…On Figure 3, the horizontal dotted line passing through Figures 3b-3d  −=  . For comparison, we learn from the Zeeman splitting that SOCs lead to a multitude of distinct energy levels (or frequencies) [32,34]. The selection rule considered in [34] is executed by eliminating one term from a two-term Hamiltonian.…”