Theoretical Physics Seminar

Since the discovery of the integer quantum Hall effect and its topological interpretation, topological materials have been predicted and realized in a wide variety of experimental platforms, including electronics, photonics, and ultra-cold atomic systems. In this presentation, I will provide a brief overview of topological photonics and femtosecond laser writing. I will then discuss the experimental realization of a higher-orbital Floquet topological insulator in laser-written photonic lattices. By periodically modulating the waveguide paths and/or the refractive index along the propagation distance, we create topologically non-trivial bands and probe the backscatter-free, robust, and unidirectional edge modes. In the second part, I will highlight some intriguing aspects of topology, disorder, and optical Kerr nonlinearity.

1. T. Ozawa et al., Rev. Mod. Phys. 91, 015006 (2019)
2. S. Mukherjee and M. C. Rechtsman, Phys. Rev. X 11, 041057 (2021)
3. A. Sinha et al., Phys. Rev. A 112, 013512 (2025)
4. G. Rajeevan and S. Mukherjee, Opt. Lett. 50(2), 297 (2025)