Etchless resist-loaded microring resonators on thin-film lithium tantalate

We demonstrate monolithic, etchless dielectric-loaded microring resonators on thin-film lithium tantalate (TFLT), in which a lithographically patterned electron-beam resist strip (ARP 6200.13) serves as the permanent waveguide load on an unetched 300-nm lithium tantalate film. The devices achieve intrinsic quality factors up to 1.23×10⁶ in the C band and approximately 9.0×10⁵ in the O band, corresponding to propagation losses of approximately 0.4 dB/cm. To our knowledge, this is the first demonstration of resist-loaded microring resonators on TFLT and the highest intrinsic quality factor reported for a monolithic, etchless dielectric-loaded TFLT platform. These results establish dielectric loading as a fabrication-simplified route to high-Q integrated photonics on TFLT, reducing fabrication to a single lithography step without etching, dielectric deposition, or wafer bonding.