SnV centres in diamond are a promising candidate for quantum internet applications because of their strong spin-photon interface, long spin coherence times, and insensitivity to electric fields. Integrating them in diamond waveguides could strongly improve entanglement rates and could make for a scalable design. In this thesis, we show using simulations that rectangular <110> waveguides are good candidates for high emitter-waveguide coupling, reaching a maximum of 79%. Optimal dimensions are 250 nm x 120 nm (width x height). This also falls inside the single-mode regime for the emitted light. The measured lifetime limits for the linewidth of Γ = 25 MHz, dephasing of Γ_𝑑 = 10 MHz, and >10 seconds long spectral stability in the bulk diamond sample, together with an APD dark count rate of 171 Hz should lead to a transmission dip around resonance of Δ𝑇/𝑇 = 25%, which we predict using a different simulation. The currently obtained taper coupling from diamond waveguide to optical fiber is approximately 10%. This is probably enough to see the transmission dip, but it needs to be improved for future experiments. Post-selecting SnV centres in waveguides and using Purcell enhancement to boost ZPL emission can further improve these results.

In this thesis, we demonstrate optical trapping of HSP90 proteins in plasmonic nanoapertures to study the HSP90 conformational change. This technique is label-free and non-destructive. The resonance of the bow tie shaped plasmonic nanoaperture is used to create a very strong electric field gradient force able to trap proteins. The resonance phenomenon is also used for detecting the trapping events, using the change in transmission that results from the presence of a protein in the trap. HSP90 can be trapped very stably for upwards of 30 seconds. The signal resulting from trapping HSP90 significantly differs from signals from bead traps, especially in the low-frequency regime. We observe strong evidence for a two level system when HSP90 was incubated with AMP-PNP which should slow down the conformational change (fit with R^2=0.9988). More work is required to demonstrate whether this two level system results from the conformational change. We conclude that there is a need for more advanced statistical methods to more conclusively prove that the HSP90 undergoes conformational change between two main levels and suggest further improvements to the experiments.