For quantum technologies to develop in the future, we need to create and manipulate systems
of increasing complexity. Consequently, a number of challenges must be overcome when
it comes to controlling, calibrating, and validating quantum states and their dynamics.
There is no doubt that a quantum computer will be the only way to simulate large-scale quantum
systems fully; however, classical characterisation and optimisation methods will continue to play
a critical role in the process. In this thesis, we look at one such adaptive method of characterising
the dynamics of a quantum system. We provide theoretical and experimental results on the study
of {T1, T∗2, T2} for a single qubit. We also provide results for the case of multiparameter estimation
and finish the discussion on adaptive estimation with an experiment on frequency estimation via
Ramsey measurement.
Spin-based quantum emitters have shown great promise to be the ideal platforms for quantum applications, particularly quantum networking. However, most of these suffer from large
inhomogeneous broadening and emit outside the telecom band. In the second part of this thesis,
we look at optical, electronic and charge state properties of vanadium (V) defect in SiC with the
goal of its use in quantum networking applications owing to O-band emission and ultra-narrow
inhomogeneous broadening
