Distributed entanglement is a means of distributing computation across modular quantum processors. The quality of the entanglement between networked quantum technologies will be contingent upon the quality of their light-matter interconnects. Semiconductor colour centre spin-photon interfaces can be entangled by indistinguishable photon emission and integrated with photonic circuits forming scalable solid-state quantum information platforms. We incorporate single silicon T centre colour centres into integrated nanophotonic cavities and resolve spin-selective optical transitions with efficient optical emission suitable for high-fidelity entanglement distribution. In this work, we demonstrate optically resolved spin states of single T centres in nanophotonic cavities as a platform for remote entanglement. Thousands of T centre devices are fabricated on chip and screened at room temperature and at cryogenic temperatures between 1K and 2.5K using automated measurement routines. Cavity-coupling enhances the T centre optical emission rate by an order of magnitude through the Purcell effect and increases the emission efficiency to near unity. Instantaneous linewidths in integrated devices are sufficient for high-fidelity remote entanglement. Spectral diffusion from crystal damage and nearby interfaces causes the emission frequency to vary in time and limits remote entanglement rates. We characterize spectral diffusion processes in cavity devices by photon correlation experiments and present techniques for reducing wandering. A quantum non-demolition measurement of the nuclear spin is dependent on the cyclicity of the optical transition addressing the electron spin states. We investigate the temperature dependence of the rate at which cavity coupled T centres lose spin polarization during spin-selective resonant excitation and photon emission. These results demonstrate that bright, telecom spin-photon emitters can be integrated into silicon photonic circuits, paving the way for large-scale telecom-band quantum networks.

In the subcycle optical regime, the quantum description of ultrashort pulses no longer has a clear correspondence to the classical theory. We describe the ambiguity with the quantum optical framework in the regime where the slowly varying envelope approximation no longer applies. We then propose possible experimental methods to investigate the quantum description of subcycle pulses.

The research in my group spans both quantum technology and quantum biology, and these two areas sometimes mirror and influence each other in our choices of specific research topics. In this talk, I will try to illustrate these parallels and connections between technology and biology with a few examples across the areas of quantum communication, quantum sensing, and quantum computing. As one common theme, photons, spins, and their interactions play important roles in all of these areas.

LiDARs with entangled light sources (such as quantum illumination) have been reporting impressive enhancement over classical LiDARs in noise resilience and sensitivity. However, their low power quantum sources (single photon level at best) cannot offer the operating distance offered by high power classical sources which are deployed in, and indispensable for, practical far-reaching (km range operating distance of moving targets) LiDAR applications. The quantum inspired LiDAR discussed in this talk inherits the advantages of quantum LiDAR while completely circumvents their power limitations. It is based on two novel principles simultaneously: (1) using high power classical time-frequency correlation that is closely related to non-classical time-frequency entanglement and (2) using a novel frequency conversion technique to analyze such correlation with unprecedented efficiency and accuracy. The LiDAR proposed, analyzed, and demonstrated combines the enhancement of quantum LiDARs and practical implementation of classical LiDARs. It exhibits unrivaled performance in noise rejection, sensitivity, detection range and resolution, compared to other published work in the field to date as will be discussed. More specifically, the LiDAR receiver used here is almost completely immune to indistinguishable jamming or crosstalk noise that is impossible to reject using conventional time-frequency filtering techniques. This is simply the highest noise resilience reported and the closest report is 30 dB smaller and it is fully quantum on optical bench with a target that is in fiber. Such resilience to indistinguishable noise (that is in band and cannot beremoved by filtering) also allows for clandestine operation; meaning that the LiDAR transmitter can be completely invisible to the target object or other unauthorized receivers.