[Host: Prof. Utpal Chatterjee]
Optical photons are excellent flying qubits for long-distance quantum networks due to negligible thermal noise and decoherence at room temperature. In this talk, I will discuss how frequency encoding can be combined with nonlinear optics and fiber and integrated photonic technologies to address challenges in scaling future photonic quantum networks. Frequency multiplexing has had a profound impact on classical telecommunication networks, creating low loss and inexpensive hardware that can be exploited for quantum applications. I will describe quantum photonic applications where frequency encoding provides a distinct advantage in terms of scaling losses and resource overhead compared to polarization, spatial or temporal mode encoding.
Coherent manipulation of light in the frequency domain at the single-photon level requires a strong, noise-free nonlinear process. I will discuss our implementation of four-wave mixing (FWM) in a commercial dispersion-shifted fiber to achieve quantum frequency conversion with near-unity efficiency and low noise. I will discuss how we used this process as an active "frequency switch" to realize a low-loss multiplexed single-photon source that can be scaled to the deterministic regime. Next, I will discuss how we used this process as a frequency beam-splitter to demonstrate two-photon Hong-Ou-Mandel type interference between entangled photons of different colors- a hallmark of quantum indistinguishability. Finally, I will discuss our realization of a FWM-based "time lens" for the generation and detection of single-photon waveforms with picosecond resolution.
Based on Joshi et al., Nat. Comm. 9, 847 (2018), Joshi et al. Phys. Rev. Lett. 124, 143601(2020)
Condensed Matter Seminar
Wednesday, November 3, 2021
Online, Room via Zoom
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