According to Science and Technology Daily report, the University of Science and Technology of China Guo Guangcan academician team Ren Xifeng research group and foreign counterparts, based on an optical quantum integration chip, in the international first demonstration of the four-photon nonlinear generation process of interference. The related results were published on Jan. 13 in Optica, a leading academic journal on optics.
▲ Integrated optical quantum chip for realizing four-photon nonlinear quantum interference | Source: University of Science and Technology of China website
Quantum interference is the basis of many quantum applications, especially nonlinear interference processes arising from path indistinguishability have attracted increasing attention in recent years, says the University of Science and Technology of China. Although two-photon nonlinear interference processes have been realized for more than two decades and applied in many emerging quantum technologies, it was not until 2017 that people theoretically extended the phenomenon to multi-photon processes, but no new progress has been obtained experimentally due to the need for extremely high phase stability and path coincidence requirements. The optical quantum integrated chip, with its extremely high phase stability and reconfigurability, has gradually developed into an ideal platform for demonstrating new quantum applications and developing new quantum devices, as well as providing the possibility for the realization of multi-photon nonlinear interference studies.
Based on the previous work, the research group, in collaboration with Prof. Mario Krenn of Max Planck Institute for Optical Science, has further cascaded the multiphoton quantum light source module, filter module and delay module for the first time in the world. The coherent phase length and phase extinction process of the nonlinear generation process has been demonstrated for the first time in the world. The two-photon compliance does not observe any significant change with phase, which is consistent with theoretical expectations. The whole experiment was done on a silicon-based integrated photonic chip with a size of only 3.8 × 0.8 mm2.
The results successfully extend the two-photon nonlinear interference process to multi-photon processes, laying the foundation for many new applications such as the preparation of new quantum states, remote quantum metrology, and the observation of new nonlocal multi-photon interference effects.
