IPB Colloquium by Marko Lončar

You are cordially invited to the IPB COLLOQUIUM which will be held on Wednesday, 5 July 2023 at 12:00 in the “Zvonko Marić” lecture hall of the Institute of Physics Belgrade. The talk entitled

Quantum optical interconnects

will be given by Prof. Dr. Marko Lončar (School of Engineering and Applied Sciences, Harvard University, USA). The abstract of the talk:

As quantum information technology matures and becomes more complex, so do the needs for interconnecting disparate quantum subsystems (computers, networks, sensors) into larger quantum networks. Thus, developing reliable quantum interconnects (QuICs) is emerging as one of the central goals for quantum information science and technology. This is a challenging task due to the variety of materials (e.g., superconductors, semiconductors, trapped atoms), qubits (spin, flux, charge, photon), and frequencies (microwave to optical) used. Moreover, QuICs must span a wide range of length scales, including chip-scale interfaces between quantum memories and processors, lab-scale links for modular quantum computers, and a continental-scale quantum internet.

In this talk we will describe our activities aimed at realization of two important QuICS: quantum repeater (QR) and quantum transducer (QT). Crucial components of QR is an optically addressable quantum memory based on silicon vacancy color center in diamond [1]. To enable efficient interaction between this spin qubit and optical photons, optical cavities are fabricated directly in diamond [2]. Next, thin film lithium niobate (TFLN) photonic platform [3-4] is used to control spectral, temporal, and spatial properties of emitted photons. Our QT is also based on TFLN platform [5, 6] using its ultra-low loss and large electro-optic coefficient. Here, single microwave photon, coupled to superconducting (SC) qubit, can be used to modulate optical signals stored in coupled optical ring resonators.

[1] M. Bhaskar et al., Nature 580, 60 (2020).
[2] A. Sipahigil et al., Science 6314, 847 (2016).
[3] D. Zhu et al., Adv. Opt. Photonics 13, 242 (2021).
[4] D. Renaud et al., Nat. Commun. 14, 1496 (2023).
[5] Y. Hu et al., Nature 599, 587 (2021).
[6] J. Holzgrafe et al., Optica 7, 1714 (2020).