AQP Seminar: Light propagation through non-Hermitian 2D honeycomb Photonic lattice, and interfacial chiral modes in threefold topological semimetal

Aalto Quantum Physics Seminar (Zoom). Speaker: Dr. SK Firoz Islam (Aalto University)
AQP seminar


A two-dimensional (2D) photonic lattice (PhL) has emerged as a versatile platform in engineering the optical analogs of most of the interesting quantum phenomena related to the nontrivial band topology occurring in 2D condensed matter systems. In this talk, I will discuss on what will happen to the optical analog of Klein tunneling process through a loss/gain media (non-Hermitian). Using standard scattering matrix approach, we reveal that there exists a critical length of the non-Hermitian region for which the 2D PhL undergoes a phase transition from light amplifier to light generator[1].
In the second part, I will discuss electronic band structure modulation of a threefold topological semimetal by shining light. The effects of light is treated perturbatively by using Floquet theory, followed by Floquet-Magnus expansion. We show that a pair of interfacial chiral mdoes between two regions of the semimetal, illuminated to the left handed and right handed polarized light, emerge among which one is topological another is non-topological[2].


[1] SK Firoz Islam et al. “Propagation of light through an amplifying honeycomb photonic lattice”. In: Physical Review A 102, pp. 043504 (2020)

[2] SK Firoz Islam et al. “Photoinduced interfacial chiral modes in threefold topological semimetal”. In:  Physical Review B 100, pp. 165302 (2019).

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