Evaluation of single silicon vacancy centers in nanodiamonds created by ion implantation at cryogenic temperatures

Abstract Silicon vacancy (SiV) centers in diamonds have attracted much attention because of their stability and narrow emission linewidth, and are promising for applications in quantum information technology. SiV-center-encapsulated nanodiamonds have also attracted much attention because of their potential to be coupled to various photonic devices. One efficient way to fabricate nanodiamonds that contain SiV centers is Si ion implantation into nanodiamonds. However, the evaluation of a single SiV center in a nanodiamond produced by this method at low temperatures has not been performed. In this study, we report on the optical properties of a single SiV center in a nanodiamond produced by ion implantation at cryogenic temperatures. The emission spectrum from a single SiV center ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>g</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:mo stretchy="false">(</mml:mo> <mml:mn>0</mml:mn> <mml:mo stretchy="false">)</mml:mo> <mml:mo>=</mml:mo> <mml:mn>0.19</mml:mn> </mml:mrow> </mml:math> ) was observed with four distinct fine splittings of the zero-phonon line (ZPL) at 4 K. At an excitation power of 50 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mi>μ</mml:mi> </mml:mrow> </mml:mrow> </mml:math> W, the full width at half maximum of the ZPL reached the spectrometer resolution limit (0.09 nm). The temperature dependence of the emission peak is consistent with that of the emission coming from an SiV center under high strain. The results obtained in this work suggest that nanodiamonds containing single SiV centers formed using this method will be an important building block for the realization of quantum information applications.