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DOE OSTI · 2568394

X-ray Parametric Down Conversion at an XFEL

Hartley, Nicholas J. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Osaka Univ., Suita (Japan)]·Baxter, James [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)]·Curtis, Scott [Brigham Young Univ., Provo, UT (United States)]·Daisuke, Okhura [Osaka Univ., Suita (Japan)]·Halavanau, Aliaksei [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)]·Carpenter, Abigail [Brigham Young Univ., Provo, UT (United States)]·Hussain, Janita [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)]·Osaka, Taito [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo (Japan)]·Ozaki, Norimasa [Osaka Univ., Suita (Japan)]·Sandberg, Richard [Brigham Young Univ., Provo, UT (United States)]·Shwartz, Sharon [Bar-Ilan Univ., Ramat Gan (Israel)]·Taketoshi, Kai [Osaka Univ., Suita (Japan)]·Yamagata, Naoki [Osaka Univ., Suita (Japan)]·Glenzer, Siegfried [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)]
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Abstract

Understanding and harnessing X-ray quantum effects could open new frontiers in imaging and quantum optics. In this study, we measured the process of X-ray Parametric Down Conversion, where a single high-energy X-ray photon splits into two lower-energy photons. Using the SACLA X-ray Free Electron Laser in Japan at 9.83 keV, we found clear evidence that pairs of photons were produced along the energy-angle relationship that conserved both energy and momentum, as predicted for down-conversion, and consistent with quantum entanglement of X-ray photons. By matching specific photon pairs for energy and momentum conservation, we observe a signal rate of 1,250 pairs per hour, confirming that correlated photon pairs can be generated and observed in the absence of explicit time correlations. Our results show that with further refinement, the number of entangled photons produced per laser pulse could increase by an order of magnitude. This paves the way for demonstrating quantum-enhanced X-ray imaging, and confirmation of X-ray photon entanglement.

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BibTeXRIS

Hartley, Nicholas J. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Osaka Univ., Suita (Japan)], Baxter, James [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)], Curtis, Scott [Brigham Young Univ., Provo, UT (United States)], Daisuke, Okhura [Osaka Univ., Suita (Japan)], Halavanau, Aliaksei [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)], Carpenter, Abigail [Brigham Young Univ., Provo, UT (United States)], Hussain, Janita [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)], Osaka, Taito [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo (Japan)], Ozaki, Norimasa [Osaka Univ., Suita (Japan)], Sandberg, Richard [Brigham Young Univ., Provo, UT (United States)], Shwartz, Sharon [Bar-Ilan Univ., Ramat Gan (Israel)], Taketoshi, Kai [Osaka Univ., Suita (Japan)], Yamagata, Naoki [Osaka Univ., Suita (Japan)], Glenzer, Siegfried [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)]. 2025-07-07. X-ray Parametric Down Conversion at an XFEL. https://doi.org/10.1364/optica.560275

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