Lead-Vacancy Centers in Diamond Solid Immersion Lens Fabricated on HPHT-Treated Substrates

Lead-vacancy (PbV) centers in diamond are emerging as a promising quantum emitter for the implementation of large-scale quantum networks. The PbV center is expected to exhibit high robustness against temperature among group-Ⅳ vacancy centers due to the large ground state splitting, and thus to show qubit operation without a dilution refrigerator [1]. However, the fluorescence enhancement using photonic structures remains a challenge for the high-quality PbV centers formed through high-pressure and high-temperature (HPHT) annealing. In this study, we demonstrate the fabrication of the diamond solid immersion lenses (SILs) incorporating PbV centers on rough HPHT-treated diamond substrates and the enhancement of the fluorescence intensity from the PbV centers. We employed focused ion beam to fabricate SILs with a diameter of ~1 um and a height of ~0.5 um. We confirmed the enhancement of the fluorescence intensity from PbV centers under non-resonant excitation. Furthermore, transform-limited linewidths were observed under resonant excitation. Our results will pave the way for further optical and spin measurements of the PbV centers.

 

[1] P. Wang et al., ACS Photonics 8, 2947 (2021).