Towards optical readout of spin-states in Si:Se+

Synopsis

A qubit system in silicon with efficient optical control and readout of robust electronic and nuclear spin states would change the dominant industrial trends in quantum devices. Singly-ionized deep double donors in silicon have shown promise as examples of such industry-changing qubit candidates. The singly-ionized selenium donor in silicon (Si:Se+) system possesses a long-lived spin qubit with photonic access through a spin-selective optical transition. Under the assumption that this optical transition is radiatively efficient, it has been proposed that this optical transition be exploited for direct emission-based spin-state readout, or alternatively used as a much-sought-after silicon-integrated single-photon source. In the first part of this thesis, we present lifetime measurements of the optically excited state which, in turn, allowed us to determine a natural radiative efficiency of 0.80(1) %. This value is lower than previously assumed. Fortunately, this spin-photon interface can nevertheless be coupled to photonic cavity modes for indirect spin-state read-out or to improve the emission rate through the Purcell effect. In the second part of this thesis, we present the hardware and software details of an adaptable automated photonics testing system that can be used to characterize integrated photonic devices.