Integrated photonics for SiC quantum technologies

Abstract

Since the discovery of peculiar phenomena in the nano-world, at the beginning of last century, our understanding of nature at this level has being constantly improving through the establishment of quantum theory. A plethora of benefits has already been exploited in semiconductors, paving the way for the age of electronics. Despite the new, groundbreaking developments, this wasn’t but the first step on the spectrum of capabilities the quantum world could offer us. The second step that will follow is about quantum technologies exploiting the very nature of quantum physics and embracing these counter-intuitive phenomena to harness an advantage over the so far, classical operation of electronics. On this route, there are many challenges still remaining, with scalability being the toughest. Our approach to tackle this issue, is to have all components needed integrated on chip, on a fabrication friendly material. Moreover, this material has to host quantum emitters which should be easily and reliably being controlled. Such a material is silicon carbide since it’s been used for decades by the high power electronics industry while at the same time, colour centres in silicon carbide have been shown to have a high level of familiarity with the NV− centre in diamond. We aim on developing fabrication techniques that will allow us to have a reliable platform for quantum technologies. We aim on fabricating high quality factor photonic crystal cavities with embedded colour centres which would deliver high Purcell factors. Purcell factor’s importance would become prominent as we demonstrate its connection with two of the most important parameters for quantum technology applications, namely the indistinguishability and the emitter-photon coupling efficiency. Our high level of fabrication fidelity, allows us to fabricate complex cavity designs with high Q/V ratios. A simulated photonic crystal cavity design in SiC of Q/V ∼ 500, 000(n/λ) 3 will be presented and fabricated. The homebuilt confocal microscopy setup will be described in detail and its abilities will be manifested. Using this setup, we are able to measure photonic crystal cavities with Q factors as high as 7138, the highest reported in 3C-SiC. Such cavities could yield a Purcell factor of 443 and consequently indistinguishability could reach to 0.85 with coupling efficiencies of 0.97. Further efforts have to be made to characterise these parameters, as preliminary work has been made to implant colour centres in photonic crystal cavities.

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Identifiers

ORCID for Alberto Politi: orcid.org/0000-0002-3668-9474

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