Planarization of Lithium Niobate Surface Using a Thin Film Catalyst in Pure Water Pho Van Bui, Daisetsu Toh, Masahiko Kanaoka, Hiromi Okada, Satoshi Matsuyama, Kazuto Yamauchi and Yasuhisa Sano EPJ Web Conf., 266 (2022) 03006 Published online: 13 October 2022 DOI: 10.1051/epjconf/202226603006