Programme

O.12 -- Oral, VCTP-49

Date: Friday, 2 August 2024

Time: 11:35 - 12:00

Overview investigating the inverse Sauter effect in binary waveguide arrays

Minh C. Tran (1,2) and Truong X. Tran (3)

(1) Atomic Molecular and Optical Physics Research Group, Science and Technology Advanced Institute, Van Lang University, Ho Chi Minh City, Vietnam; (2) Faculty of Applied Technology, School of Technology, Van Lang University, Ho Chi Minh City, Vietnam; (3) Department of Physics, Le Quy Don Technical University, 236 Hoang Quoc Viet street, Ha Noi, Vietnam.

Waveguide arrays (WAs) are a candidate for studying many classic photonic phenomena, such as discrete diffraction [1], discrete solitons [2], and the generation of diffractive resonant radiation from discrete solitons [3]. Klein tunneling (KT) has also been investigated in BWAs both theoretically [4] and experimentally [5] and was predicted by O. Klein in 1929 [6]. According to Klein, relativistic fermions can tunnel through large repulsive potential steps, higher than the particle's energy, without the exponential decaying expected in quantum nonrelativistic tunneling processes governed by the well-known Schrödinger equation [6]. This phenomenon is due to the existence of negative-energy solutions of the Dirac equation [7]. We simulated the inverse Sauter effect by launching a Dirac soliton in binary waveguide arrays where the smooth transition region of the inverse potential step can be easily realized if we modify the effective refractive indices of the waveguides so that the smooth declining transition region of the inverse potential step can be described by a linear, exponential, or sinusoidal function [8]. As expected, if the transition obeys the linear and sinusoidal laws, then the inverse Klein tunneling is practically suppressed if the transition width is comparable to or larger than the Compton length. In this talk, we demonstrate that the analytical transmission coefficient in the discrete model with BWAs is in strikingly perfect agreement with the simulations-based results. REFERENCES [1] D. N. Christodoulides, F. Lederer, and Y. Silberberg, Nature (London) 424, 817 (2003). [2] D. N. Christodoulides and R. I. Joseph, Opt. Lett. 13, 794 (1988). [3] Tr. X. Tran and F. Biancalana, Phys. Rev. Lett. 110, 113903 (2013). [4] S. Longhi, Phys. Rev. B 81, 075102 (2010). [5] F. Dreisow, R. Keil, A. T¨unnermann, S. Nolte, S. Longhi, and A. Szameit, Europhys. Lett. 97, 10008 (2012). [6] O. Klein, Z. Phys. 53, 157 (1929). [7] H. Nitta, T. Kudo, and H. Minowa, Am. J. Phys. 67, 966 (1999). [8] M. C. Tran, Annal of Phys. 463, 169624 (2024)

Presenter: Trần Công Minh