Chiral terahertz lasing with Berry-curvature dipoles

The non-Hermitian electro-optic (EO) effect in materials with Berry-curvature dipoles (BDs) is important for applications like terahertz lasing. This study shows that a stack of low-symmetry two-dimensional materials inside a cavity supports a nonreciprocal growing mode, which generates an unstable resonance that leads to self-sustained oscillations. It is also found that the chiral nature of the Berry-dipole gain can control the laser's handedness, enhancing the design of chiral terahertz lasers.