A faster way to detect entangled photons for quantum holography

Quantum holography encodes images through pairs of entangled photons. This technique and other quantum imaging applications require two-photon coincidence imaging, a technique that retrieves spatial information about the entangled photons. Traditionally, two-photon coincidence imaging relies on camera-based methods. However, these methods suffer from low single-photon detection efficiency and require both momentum and polarization entanglement of the two photons. Camera-based methods also aren’t compatible with bright biphoton sources, limiting quantum imaging speed.

Gao et al. introduced a new method, called scanning biphoton imaging, which shows enhanced single-photon detection efficiency. The scanning-based method employs two high efficiency single-photon detectors to read out the spatial information of an entangled photon. It does not require momentum entanglement, reducing entanglement source requirements.

The authors used the method to obtain a quantum holography image, experimentally demonstrating its high signal-to-noise ratio and spatial resolution. The scanning-based method also works with bright biphoton sources, allowing faster imaging.

“Our work opens a new biphoton detection avenue for quantum imaging,” said author Xi-Lin Wang.

The authors are currently working on a second generation of the scanning biophoton imaging platform that will exhibit improved spatial resolution and light-coupling efficiency. While the first-generation platform measures the spatial information of only one of the entangled photons, they plan to make the second generation capable of dual-path scanning, which would measure the spatial information of both photons as well as the spatial information of their correlations.

“A dual-path system would provide more powerful functionality for quantum holography and other quantum imaging applications,” Wang said. “The second-generation system is expected to largely meet the requirements for super-resolution quantum imaging detection.”

Source: “Scanning biphoton phase imaging with enhanced signal-to-noise ratio for quantum holography,” by Jing Gao, Jing Wang, Wen-Zheng Zhu, Shuang-Yin Huang, Zi-Mo Cheng, Shu-Tian Xue, Li-Ping Yang, Zhi-Cheng Ren, Xi-Lin Wang, and Hui-Tian Wang, Applied Physics Letters (2026). The article can be accessed at https://doi.org/10.1063/5.0325971 .