Quantum optics with photonic manostructures - Michael Reimer

Semiconductor nanostructures can be engineered for efficient incoupling, guiding and outcoupling of light. In this talk, I will present our most recent progress on various III-V semiconductor nanowire devices to enhance the efficiency of entangled photon sources, manipulate single photons, and enhance the performance of single-photon detectors and cameras. These results are promising for photonic quantum computing, quantum networks, and sensing applications.

In the first part of my talk, recent results will be presented on the fabrication of InAsP quantum dots in InP nanowires transferred from the growth substrate onto a gold mirror using an in-situ SEM ‘nanowelding’ technique. We show enhancement of the entangled photon pair efficiency from the quantum dot to overcome the fundamental Poisson limit that hinders probabilistic entangled photon sources. We will also show our most recent work for integrating such sources in quantum networks, such as interfacing with atoms for a quantum memory and tuning the quantum dot transitions using electric field tunable devices.

Next, we show that an on-axis quantum dot inside the nanowire waveguide can be effectively realized as a ‘quantum mirror’ that reflects single photon components of incident coherent light. We achieve this reflection by incoupling light to the tapered end of the nanowire waveguide with efficiencies exceeding 90%. Interestingly, these single photons exhibit the coherence of the input laser light instead of the quantum dot emission. These results open up new avenues for exploring deterministic gates for photonic quantum computing, and entangling remote quantum dots for quantum networks.

Finally, we also show that the shape of nanowire arrays can be engineered to absorb light with near-unity efficiency in the wavelength range where commercially available semiconductor-based single-photon detectors and cameras have limited efficiency. These nanowires can also be shaped to control the spatial location of the absorption profile, which significantly improves the timing resolution of single-photon detectors without sacrificing detection efficiency.

The event is sponsored by Quantum City.