Thin-film lithium tantalate for ultraviolet integrated electro-optic modulator

Abstract The realization of integrated, high-speed ultraviolet modulation is pivotal for the advancement of quantum information processing, portable atomic clocks, and secure solar-blind communications. While mature photonic platforms have enabled sophisticated system-level integration across the visible and infrared spectral ranges, high-speed active modulation in the ultraviolet remains largely dependent on conventional bulk-crystal technologies. Consequently, a scalable integrated solution that simultaneously combines low insertion loss and extreme compactness with high modulation efficiency has remained challenging. Here, we report an integrated UV electro-optic modulator on a thin-film lithium tantalate platform. The device has a compact lumped-electrode of 200 μ m, exhibiting a measured 3 dB electrical-to-optical-to-electrical bandwidth above 40 GHz, a high modulation efficiency V π L of 85 mV ⋅ cm, and a measured electrical-to-electrical bandwidth beyond 67 GHz. This work establishes thin-film lithium tantalate as a disruptive platform for wafer-scale compatible active UV photonics, enabling the next generation of scalable quantum and communication systems.