Photonic Quantum Manipulations by Harnessing Quantum Frequency Conversion

Zi-Yu Liu^1,2*, Chin-Yao Cheng^1,2, Jiun-Shiuan Shiu^1,2, Yong-Fan Chen^1,2,3

¹Physics, National Cheng Kung University, Tainan, Taiwan
²Center for Quantum Frontiers of Research & Technology, Tainan, Taiwan
³Center for Quantum Technology, Hsinchu, Taiwan

* Presenter:Zi-Yu Liu, email:liuziyu.ncku@gmail.com

Harnessing and mastering one of the quantum information carriers—photons—is a pivotal issue in the realm of quantum information science, courtesy of their remarkable propagation speed, insensitivity to the environment, and direct connection with optical communication. In this talk, I shall present several applications leveraging quantum frequency conversion (QFC) in the four-level double-Λ system [1]. Through the inherent property of quantum interference, the scheme efficiently converts the incident field frequency, leaving all other encoded quantum states unaltered, signaling its potentiality as a quantum frequency converter. [2,3,4]. This concept, in turn, empowers us to further manipulate the quantum state between the incoming fields. When employing two input weak coherent fields, the QFC channels for both fields are phase-dependent, enabling the large cross-phase modulation between light fields [1]. Conversely, for two incident single photons, both QFC channels are no longer phase-dependent due to the uncertain nature of the relative phase between single photons. In this scenario, we can either build the color SWAP gate or create frequency Hong-Ou-Mandel interference by simply toggling the laser detuning values, thereby exchanging the color modes between single photons or producing two-photon NOON states [5]. The proposed scheme enables the diversity of photonic operations, hence illustrating potential applications in photonic quantum technologies.



References
[1] Z.-Y. Liu, Y.-H. Chen, Y.-C. Chen, H.-Y. Lo, P.-J. Tsai, I. A. Yu, and Y.-C. Chen, and Y.-F. Chen, Large cross-phase modulations at the few-photon level, Phys. Rev. Lett. 117 (20), 203601 (2016).
[2] Z.-Y. Liu, J.-T. Xiao, J.-K. Lin, J.-J. Wu, J.-Y. Juo, C.-Y. Cheng, and Y.-F. Chen, High-efficiency backward four-wave mixing by quantum interference, Sci. Rep. 7 (1), 15796 (2017).
[3] C.-Y. Cheng, J.-J. Lee, Z.-Y. Liu, J.-S. Shiu, and Y.-F. Chen, Quantum frequency conversion based on resonant four-wave mixing, Phys. Rev. A 103, 023711 (2021).
[4] C.-Y. Cheng, Z.-Y. Liu, P.-S. Hu, T.-N. Wang, C.-Y. Chien, J.-K. Lin, J.-Y. Juo, J.-S. Shiu, I. A. Yu, Y.-C. Chen, and Y.-F. Chen, Efficient frequency conversion based on resonant four-wave mixing, Optics Letters 46 (3), 681 (2021).
[5] Z.-Y. Liu, J.-S. Shiu, C.-Y. Cheng, and Y.-F. Chen, Controlling Frequency-Domain Hong-Ou-Mandel Interference via Electromagnetically Induced Transparency, Phys. Rev. A 108, 013702 (2023).

Keywords: quantum frequency conversion, double-Λ system, cross-phase modulation, Hong-Ou-Mandel interference, SWAP gate