Quantum entanglement and interference at 3 μm.

Ge, Zheng; Han, Zhao-Qi-Zhi; Yang, Fan; Wang, Xiao-Hua; Li, Yin-Hai; Li, Yan; Gao, Ming-Yuan; Chen, Ren-Hui et al. · Sci Adv · 2024

basic_science · Level V

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Abstract

Given the important advantages of the mid-infrared optical range (2.5 to 25 μm) for biomedical sensing, optical communications, and molecular spectroscopy, extending quantum information technology to this region is highly attractive. However, the development of mid-infrared quantum information technology is still in its infancy. Here, we report on the generation of a time-energy entangled photon pair in the mid-infrared wavelength band. By using frequency upconversion detection technology, we observe the two-photon Hong-Ou-Mandel interference and demonstrate the time-energy entanglement between twin photons at 3082 nm via the Franson-type interferometer, verifying the indistinguishability and nonlocality of the photons. This work is very promising for future applications of optical quantum technology in the mid-infrared band, which will bring more opportunities in the fields of quantum communication, precision sensing, and imaging.