YB 3+ /ER 3+− CODOPED GEO 2 –PBO–PBF 2 GLASS CERAMICS FOR RATIOMETRIC UPCONVERSION TEMPERATURE SENSING BASED ON THERMALLY AND NON-THERMALLY COUPLED LEVELS
KALINICHEV, A.A.,
KUROCHKIN, M.A.,
KOLOMYTSEV, A.Y.,
KOLESNIKOV, I.E.,
KHASBIEVA, R.S.,
KOLESNIKOV, E.Y.,
LÄHDERANTA, E.