High-Speed Optical Modulation via Reversible Phase Switching in PIN-PMN-PT Single Crystals

Optical scattering caused by ferroelectric-ferroelastic domain walls severely limits the electro-optical (EO) performance of PMN-PT-based crystals. Poling of the crystals with compositions near the rhombohedral-orthorhombic phase transition temperature can suppress these scattering domain walls and enhance optical transmission. However, this method requires a high-temperature poling pre-treatment, complicating device fabrication. Here, we systematically investigate electric-field-driven domain switching mechanisms in PIN-PMN-30PT single crystals under an electric field applied along [110] and introduce a treatment protocol that enables fully reversible switching between a multi-domain rhombohedral state and a single-domain orthorhombic '1O' state at room temperature. The state switching time is approximately 15 µs and can be achieved under a relatively low operating electric field, which is lower than the conventional poling field of 0.7 kV/mm reported for PIN-PMN-PT crystals. Based on this discovery, we demonstrated a low-power, room-temperature, fast optical modulation method via domain/phase switching in transparent ferroelectrics, establishing a practical pathway to achieve next-generation optical modulators.