Toward Entanglement Between Barium Ion Qubit and Telecom O-Band Photon Via Quantum Frequency Conversion

Trapped ions are excellent quantum computation and simulation platforms due to their high-fidelity single- and two- qubit gates combined with long trapping and coherence lifetimes [1-6]. For networking, our work is the first to generate telecom photons from a Ba+ ion using quantum frequency conversion (QFC) [7-9]. Recently, we demonstrated transmission of these telecom-converted single photons (~1287 nm) derived from a Ba+ ion, through an 11.2 km in-ground deployed fiber network [10]. Here, we present our efforts towards entanglement between the polarization of a telecom O-band photon and the spin state of a 138Ba+ utilizing the strong dipole S-P transition. This ion-photon entanglement allows for increased SNR over C-band photons and allows for a dramatic distance increase over the unconverted wavelength, readily enabling networking between trapped ions and preexisting fiber-optics components and deployed fiber networks [10].

[1] D. Zhu, Z.-P. Cian, C. Noel, et al.. Nat. Comm. 13, 6620 (2022)

[2] S. Blinov, B. Wu, C. Monroe. AVS Quantum Sci. 3, 033801 (2021)

[3] R. Blatt and C. F. Roos. Nat. Phys. 8, 277 (2012).

[4] C. Monroe, W. C. Campbell, et al.. Rev. Mod. Phys. 93, 025001 (2021).

[5] T. P. Harty, D. T. C Allcock, et al.. Phys. Rev Lett. 113, 220501 (2014).

[6] P. Wang, C.-Y. Luan, et al.. Nat Comm 12, 233 (2021)

[7] J. Hannegan, U. Saha, J. Siverns, Q. Quraishi, et al.. Appl. Phys. Lett. 119, 084001 (2021)

[8] J. Hannegan, J. Siverns, Q. Quraishi, Q. Phys. Rev. A 106:042441 (2022).

[9] U. Saha, J. Siverns, J. Hannegan, Q. Quraishi, E. Waks. ACS Photon. 2023, 10, 8, 2861-2865 (2023)

[10] M. Diaz, M. Kwan, J. Hannegan, J. Siverns, U. Saha, E. Waks, Q. Quraishi. Damop poster (2023)