<p>邀请人：吴令安 研究员</p>
<p>联系人：孙丽（18601300418）</p>
<p>主办单位：中国科学院物理研究所应用物理中心</p>
<p>报告人简介</p>
<p>Professor Ou obtained his BS in 1984 from Peking University and Ph.D. in 1990 from University of Rochester. He is now a Chair Professor at the City University of Hong Kong. He is an expert in quantum optics, especially in quantum interference, for which he is the co-inventor of the well-known Hong-Ou-Mandel two-photon interferometer and more recently the SU(1,1)-type of nonlinear quantum entangled interferometer. He pioneered the field of multi-photon interference, which he summarized in the monograph “Quantum Multi-Photon Interference” published by Springer in 2007. His current research focuses on quantum metrology, quantum sensing, quantum amplifiers, quantum state engineering, quantum information and communication, and more fundamental quantum measurement and quantum coherence problems. He is a fellow of American Physical Society and of Optica (formerly Optical Society of America), and is the Associate Editor of Optica Quantum.</p>
<p>报告摘要</p>
<p>Quantum noise in the internal modes of an amplifier is responsible for the excess noise introduced to the amplifier’s output, leading to degradation of the signal-to-noise in the output as compared to the input. Reduction of this noise requires manipulation of the internal modes from outside by preparing them in some special quantum states, among which quantum correlated states were recently used. On the other hand, the amplifier’s internal modes are also correlated to the output, so, by tapping part of the output and feeding back to the amplifier, we can achieve the same feat. We present a detailed study of this novel approach on different amplification platforms. The feedback is found to be phase-sensitive, thus forming an SU(1,1)-type of nonlinear interferometer. The feedback can also lead to onset of oscillation, making the interferometer active and self-sustained. Such a device should find applications in quantum sensing.</p>