Photonic Landau levels in an astigmatic frequency-degenerate laser

Landau levels refer to the quantization of electron energy levels under magnetic fields which have recently been extended to photonic systems through the judicious design of pseudomagnetic fields. However, established approaches towards photonic Landau levels have primarily relied on complex artificial metamaterials or passive multifolded cavities. Here, utilizing an active symmetry-breaking angular momentum laser with simple displacement tuning of intracavity astigmatic elements for generating structured beams with controlled frequency-degeneracy, we demonstrate that the physical nature of such frequency-degeneracy can be modeled effectively as the quantization of photon energy levels. This work provides a compact solution to control complex quantized modes in structured light laser platform. Related potential applications of these Landau level lasers also permit advancing photonic quantum Hall effects and topological information. Landau levels has recently been extended from electronic to photonic systems through the judicious design of pseudomagnetic fields. The authors utilize an active symmetry-breaking angular momentum laser to demonstrate that the physical nature of astigmatic frequency-degeneracy of laser can be modeled effectively as the Landau quantization of photon energy levels, providing a compact solution and new platform to study topological physics.