Presentation Information
[10a-B11-9]Strain Induced Landau Rainbow in Photonic Crystal
〇Guangtai Lu1, Satoshi Iwamoto1 (1.RCAST, Univ. Tokyo)
Keywords:
Photonic crystal,Synthetic gauge field,Rainbow effect
Strain-induced synthetic fields have become a powerful tool for controlling classical waves. A prominent example is the formation of Landau levels through strain-induced pseudomagnetic fields in honeycomb lattices. However, Landau quantization alone does not in general define localized resonances, which is important in photonic applications. In an ideal uniform pseudomagnetic field, each Landau level is highly degenerate, with states share the same eigenfrequency while being associated with different spatial distributions. Additional adjustments are typically required to resolve this degeneracy into modes that are spatially localized. Recently, strained photonic crystals were shown to naturally support guided modes associated with dispersive Landau levels, an effect attributed to higher-order corrections in continuum photonic systems. Nevertheless, how such intrinsic corrections can give rise to discrete localized resonances remains unexplored.
Here, we report that in a triaxial strained photonic crystal, this degeneracy in Landau levels is automatically lifted. Without additional adjustment, Landau levels induced by synthetic magnetic field naturally split into sub-levels and form localized resonances. We recognize such splitting as the result of an accompanying scalar potential field due to the deformation of unit cell geometry. Moreover, in the zeroth Landau level, these sub-levels are spatially organized, with intensity maxima that move progressively outward from the device center. This behavior forms a frequency-position mapping, which corresponds to a Landau rainbow effect.
Here, we report that in a triaxial strained photonic crystal, this degeneracy in Landau levels is automatically lifted. Without additional adjustment, Landau levels induced by synthetic magnetic field naturally split into sub-levels and form localized resonances. We recognize such splitting as the result of an accompanying scalar potential field due to the deformation of unit cell geometry. Moreover, in the zeroth Landau level, these sub-levels are spatially organized, with intensity maxima that move progressively outward from the device center. This behavior forms a frequency-position mapping, which corresponds to a Landau rainbow effect.