Near-field levitated optomechanics with a photonic crystal cavity

Optically levitated dielectric particles has recently emerged as a new system in quantum optomechanics. It offers excellent mechanical coherence under high vacuum and a possibility to optically configure potential landscapes. An outstanding problem is the lack of methods to manipulate the particle at the quantum level. Here we introduce a nanophotonic interface that addresses this challenge. By optically trapping a 150 nm silica particle and placing it in the near field of a nanofabricated photonic cavity, we achieve a single-photon optomechanical coupling of up to g₀/2π = 9 kHz. Combined with an efficient guiding of light through the nanophotonic structure, we demonstrate a 'per-photon' displacement sensitivity increased by two orders of magnitude compared to previous experiments using far-field detection. I will discuss future outlook of the work, including several room-temperature quantum experiments that can be performed.