  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 in-depth study the
spin-optical dynamics of single silicon vacancy center at hexagonal lattice
sites, namely V1, in 4H-polytype silicon carbide. By utilizing resonant and
above-resonant sub-lifetime 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 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.
