Progress in photonic quantum information

Shigeki Takeuchi

Recent technological progress in the generation, manipulation and detection of individual single photons has opened a new scientific field of photonic quantum information. This progress includes the realization of single photon switches, photonic quantum circuits with specific functions, and the application of novel photonic states to novel optical metrology beyond the limits of standard optics. In this review article, the recent developments and current status of photonic quantum information technology are overviewed based on the author's past and recent works.

Linda Sansoni

Jiang Yun-kun

The development of preparing two-photon entangled state by spontaneous parametric down-conversion, its principle and use in quantum information are described, and the domestic progress in this fieldis introduced.

John G. Rarity

Radhika Rangarajan, Luis Edgar Vicent, Alfred B. U’Ren +1 more

The eventual success of optical quantum information (QI) processing depends critically on the available technologies. Photons produced via the nonlinear process of spontaneous parametric downconversion (SPDC) have now been used in a vast array of experiments in optical quantum computing and long-distance quantum communication. However, almost no source to date has been fully optimized. Here, we describe our progress in engineering an ideal photon-pair source for optical quantum information processing – polarization-entangled photons made indistinguishable by engineering spatio-spectral unentanglement at the source. We present solutions for several key challenges encountered in the development of the indistinguishable source. We expect such a source to directly translate into significantly enhanced QI protocols with higher rates, fidelities and efficiencies.

Pramod Kumar, Alan L. Migdall, Seungmin Nam +2 more