The paper Visible upconversion luminescence of doped bulk silicon for a multimodal wafer metrology. written by Boris I. Afinogenov, Anton N. Sofronov, Ilya M. Antropov, Nikita R. Filatov, Anton S. Medvedev, Alexander S. Shorokhov, Vladimir N. Mantsevich, Natalia S. Maslova, Taehyun Kim, Eunhee Jeang, Ingi Kim, Minhwan Seo, Kyunghun Han, Sangwoo Bae, Wondon Joo, Hosun Yoo, Vladimir O. Bessonov, Andrey A. Fedyanin, Maksim V. Ryabko, and Stanislav V. Polonsky has been published in Optics Letters.