Zero-phonon line characteristics of SiV center emission in microcrystalline diamond probed with intensive optical excitation

Zero-phonon line (ZPL) position, broadening and intensity of the SiV center emission was monitored in microcrystalline diamond film by using intensive laser excitation of 2.54eV photon energy. Excitation intensity was varied from 150kW/cm2 to 700kW/cm2 to explore changes in the emission region of the zero-phonon line. Two types of characteristic behavior were found in diamond microcrystals. Both the ZPL position and half width of the SiV center emission remain nearly the same in the one type of microcrystalline samples, whilst considerable broadening and red shift of the ZPL of SiV center with the increasing intensity was observed in the other type of microcrystalline samples. GR1 defect center emission under intensive laser excitation is discussed as a possible origin of the observed changes. •We analyzed the photoluminescence spectral shape of Si–V color center in microcrystalline diamond films by using intensive laser excitation of 2.54eV photon energy.•Photoluminescence measurements were taken using different surface power density varied from 150kW/cm2 to 700kW/cm2.•It was found that the increasing excitation surface power density causes remarkable changes in the Si–V peak region of the PL emission spectrum in one type of microcrystallites, while in case of the other type of microcrystallites the spectral shape characteristics remains almost the same.•GR1 defect center emission was discussed as a possible origin of the peak position shift and broadening of SiV center ZPL.