Local laser heating effects in diamond probed by photoluminescence of SiV centers at low temperature

Diamond is generally considered to have high thermal conductivity, so little attention has been paid to the laser heating effects at low excitation power. However, defects during the growth process can result in a great degradation of thermal conductivity, especially at low temperatures. Here, we observed the dynamic redshift and broadening of zero phonon line (ZPL) of silicon-vacancy (SiV) centers in diamondin the experiment. Utilizing the intrinsic temperature response of the fine structure spectra of SiV as a probe, we confirmed that the laser heating effect appears and the temperature rising results from high defect concentration. By simulating the thermal diffusion process, we have estimated the thermal conductivity of around 1 W/(mK) at the local site, which is a two order magnitude lower than that of single-crystal diamond. Our results provide a feasible scheme for characterizing the laser heating effect of diamond at low temperatures.