Optical transition measurements in laser active medium candidates: Application to color centers

Isaac Harris, Cathryn P. Michaels, Kevin C. Chen +16 more

A quantum register coupled to a spin-photon interface is a key component in quantum communication and information processing.Group-IV color centers in diamond (SiV -, GeV -, and SnV -) are promising candidates for this application, comprising an electronic spin with optical transitions coupled to a nuclear spin as the quantum register.However, the creation of a quantum register for these color centers with deterministic and strong coupling to the spin-photon interface remains challenging.Here, we make first-principles predictions of the hyperfine parameters of the group-IV color centers, which we verify experimentally with a comprehensive comparison between the spectra of spin active and spin neutral intrinsic dopant nuclei in single GeV -and SnV -emitters.In line with the theoretical predictions, detailed spectroscopy on large sample sizes reveals that hyperfine coupling causes a splitting of the optical transition of SnV -an order of magnitude larger than the optical line width and provides a magnetic field insensitive transition.This strong coupling provides access to a new regime for quantum registers in diamond color centers, opening avenues for novel spin-photon entanglement and quantum sensing schemes for these well-studied emitters.

Rajarshi Roy, L. Mandeļ

Naoya Morioka, Di Liu, Öney O. Soykal +8 more

Color centers in silicon carbide are emerging candidates for distributed spin-based quantum applications due to the scalability of host materials and the demonstration of integration into nanophotonic resonators. Recently, silicon vacancy centers in silicon carbide have been identified as a promising system with excellent spin and optical properties. Here, we fully study the spin-optical dynamics of the single silicon vacancy center at hexagonal lattice sites, namely V1, in 4H-polytype silicon carbide. By utilizing resonant and above-resonant sublifetime pulsed excitation, we determine spin-dependent excited-state lifetimes and intersystem-crossing rates. Our approach to inferring the intersystem-crossing rates is based on all-optical pulsed initialization and readout scheme, and is applicable to spin-active color centers with similar dynamics models. In addition, the optical transition dipole strength and the quantum efficiency of V1 defect are evaluated based on coherent optical Rabi measurement and local-field calibration employing electric field simulation. The measured rates well explain the results of spin-state polarization dynamics, and we further discuss the altered photoemission dynamics in resonant enhancement structures such as radiative lifetime shortening and Purcell enhancement. By providing a thorough description of the V1 center's spin-optical dynamics, our work provides deep understanding of the system, which guides implementations of scalable quantum applications based on silicon vacancy centers in silicon carbide.

R F Mardanov, Ю Е Польский

V. Dohm

Hebin Li

Defect-induced color centers in solids are promising candidates for applications in quantum information science. Quantum sensing applications and quantum-logic operations can utilize quantum entanglements mediated by coherent coupling between color centers. Therefore, a critical step is to enable deterministic coherent coupling of individual optically addressable color centers. This work reports our effort of probing coupling between SiV color centers by using optical two-dimensional coherent spectroscopy (2DCS), a technique that provides an extremely sensitive and background-free detection of coupling. Arrays of SiV color centers were fabricated by implanting Si ions into a diamond substrate with a focused ion beam. Optical 2DCS measurements on these color center arrays revealed coherent coupling between single color centers.