Dynamic control of optical nonreciprocity through nonlinear process induced by photoisomerization

Dynamic control of optical nonreciprocity is crucial for optical communication. This work theoretically demonstrates a dynamic optical nonreciprocal control using a dual resonance microcavities. The dual resonance microcavities is a non-Hermitian heterostructure with one cavity containing photoisomerizable molecules while the second cavity is passive. The system achieves low-power nonreciprocal transmission through trans-cis isomerization-induced refractive index modulation. Theoretical analysis reveals that light-controlled isomeric index changes induce quasi-static optical bistability, with nonlinear saturation thresholds strongly dependent on incident polarization and external pumping. A broad range of photoisomerizable molecules offers a wide range of index modulation time, from picosecond to microsecond, that means a broad temporal range in dynamic control of nonreciprocity. Notably, the system enables reversible switching of optical isolation direction via polarization control and external pumping. This work establishes a new paradigm for active nonreciprocal control in dissipative systems, with promising applications in reconfigurable optical isolators and nonlinear photonic memories. © 2025 Elsevier B.V.