Influence of optically active defects on thermal conductivity of polycrystalline diamond Qinyu Kong, Alvarado Tarun, Chuan Ming Yap, Siwei Xiao, Kun Liang, Beng Kang Tay and Devi Shanker Misra Eur. Phys. J. Appl. Phys., 80 2 (2017) 20102 Published online: 27 October 2017 DOI: 10.1051/epjap/2017170217