Programme

P.52 -- Poster, VCTP-48

Date: Thursday, 3 August 2023

Time: 08:30 - 10:00

Investigating the Klein tunneling effect through a rectangular potential barrier in binary waveguide arrays

Minh C. Tran (1,2,3) and Truong X. Tran (4)

(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) Nuclear Training Center, VINATOM, 140 Nguyen Tuan street, Ha Noi, Vietnam; (4) 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, which are higher than the energy of the particle, 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 investigated KT through a rectangular potential barrier in binary waveguide arrays. The rectangular potential step in this platform is created by introducing a certain offset for waveguides’ refractive indices. We analytically derive the transmission coefficients of plane waves through the rectangular potential step in BWAs and also in the continuous model in free space [8]. 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. 450, 169241 (2023)

Presenter: Trần Công Minh