Quantum emitters coupled to optical nanowaveguides
We couple single colloidal quantum emitters to optical nanowaveguides such as tapered optical nanofibers, collecting their emission into a single guided mode toward compact integrated single-photon sources.
Efficient single-photon sources are a key resource for quantum technologies, from optical quantum computing to quantum key distribution and quantum metrology. Our goal in this axis is to interface bright, room-temperature solid-state single-photon emitters with optical nanowaveguides — in particular tapered optical nanofibers (TONFs) — so that the emitted photons are funnelled directly into a single guided mode and delivered in-fiber.
Depositing emitters on a nanofiber
To bring an emitter into the evanescent field of the nanofiber waist, we rely on two complementary approaches:
- Droplet deposition. We use a droplet deposition technique to deposit colloidal emitters directly onto the nanofiber, detailed in S. Pierini et al., arXiv:2005.09359. This method is well suited to solution-processed colloidal quantum emitters.
- Deterministic placement. We can also use a micromanipulator to deterministically position individual nano-objects on the nanofiber, one at a time, when precise control over the emitter location is required.
Coupling into the guided mode
With this approach, a single emitter sitting on the waist can be coupled with up to 30% efficiency into the guided mode of the nanofiber, while the full transmission of the tapered nanofiber remains greater than 98%. Together, these figures are the key ingredients toward a compact, fully fiber-integrated single-photon source operating at room temperature.