Design photonic circuit for cavity enhanced quantum sensor network

Quantum sensors can detect magnetic fields and other physical quantities, with unprecedented spatial resolution and sensitivity. A diamond color center based quantum sensing system, when integrated with photonics and electronics, can provide high sensitivity along with compactness and robustness. Such an on-chip, solid-state system will be very attractive for various fields ranging from biomedical to extreme environment applications [1-3]. The performance of the sensors is expected to be improved by making photonic cavity structure in the diamond connected with carefully designed photonic components, integrating deterministic photon sources, and single-photon detectors etc. Coupling the color center qubits with such a photonic network, the measurement precision of a quantum metrology system can be pushed beyond the standard quantum limit (SQL) by using entangled quantum sensors, which has been demonstrated recently with diamond color center based quantum sensors [4].

A system using levitated mircomagnet combined with the quantum sensor using diamond color center can be used to comprise an entangled quantum sensors network. In this scheme, a small magnetic particle will be levitated in a MEMS cavity in a silicon with a strong magnetic field by superconducting coil and color-center in diamond will be coupled gyroscopically with the motion of the particle. Levitated microobject is in general reported to provide a very high Q factor because of the completely isolated system. Theoretical study of the system operating at a cryogenic temperature of 4K predicts a very high sensitivity (approaching 1013m/s2 /Hz1/2). The measurement precision of such a quantum metrology system can be pushed beyond the standard quantum limit (SQL) by using entangled quantum sensors. Recently, this has been demonstrated with diamond color center based quantum sensors [5, 6].

In this project, we design a suitable quantum photonic integrated circuit (QuPIC) for diamond color center spins, with which an on-chip, programmable quantum metrology system can be implemented. and Heisenberg-limited sensing precision can be approached. Furthermore, we will design diamond nanophotonic cavities to couple with levitated micromagnets as a step towards an on-chip, integrated and programmable quantum inertial sensor system. Such an inertial sensor system will enable a performance close to the fundamental quantum limit, compact form factor & robust design - fulfilling very well the stringent requirements for space applications.

[1]. C.‚ÄČL. Degen, and et al., Quantum sensing, Rev. Mod. Phys. 89, 035002 (2017)
[2]. S. B.-Esfahani, and et al., Integrated quantum photonic sensor based on Hong-Ou-Mandel interference, Opt. Express 23, 16008-16023 (2015)
[3] N. Aslam, and et al., Quantum sensors for biomedical applications, Nature Reviews Physics (2023)
[4]. T. Xie, and et al., Beating the standard quantum limit under ambient conditions with solid-state spins, Vol. 7, No. 32, (2021)
[5]. V. Cimini, and Et al., Deep reinforcement learning for quantum multiparameter estimation, Advanced Photonics, Vol. 5, Issue 1, 016005 (2023)
[6]. J. Gieseler, and et al., Single-Spin Magnetomechanics with Levitated Micromagnets, Phys. Rev. Lett. 124, 163604 (2020)