2017/09/28 by Tamar Goldzak, Alexei A. Mailybaev, Nimrod Moiseyev · 1 voice · 1 citation
Physics and Astronomy · #Advanced Fiber Laser Technologies #Nonlinear Photonic Systems #Quantum Mechanics and Non-Hermitian Physics #physics.optics
paper · pdf · doi:10.1103/physrevlett.120.013901
published as Phys. Rev. Lett. 120, 013901 (2018) · 5 pages, 4 figures
arxiv published 2017/09/28 · arxiv created 2018/01/03 · openalex publication_date 2018/01/03 · arxiv updated 2018/01/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Almost twenty years ago the light was slowed down to less than 10-7 of its vacuum speed in a cloud of ultracold atoms of sodium. Upon a sudden turn-off of the coupling laser, a slow light pulse can be imprinted on cold atoms such that it can be read out and converted into photon again. In this process, the light is stopped by absorbing it and storing its shape within the atomic ensemble. Alternatively, the light can be stopped at the band edge in photonic-crystal waveguides, where the group speed vanishes. Here we extend the phenomenon of stopped light to the new field of parity-time (PT) symmetric systems. We show that zero group speed in PT symmetric optical waveguides can be achieved if the system is prepared at an exceptional point, where two optical modes coalesce. This effect can be tuned for optical pulses in a wide range of frequencies and bandwidths, as we demonstrate in a system of coupled waveguides with gain and loss.