报告时间；6月8日 上午 9：30；
报告地点：理六栋四楼会议室；
报告人：李润兵 副研究员 中科院武汉物理与数学研究所
报告题目：All-Optical, High-Fidelity Polarization Gate Using Room-Temperature Atomic Vapor
报告摘要：
The ability to directly control the slowly varying phase of a signal wave by various gated operations is one of central importance to any information technologies, such as optical telecommunications and quantum information science. Several works have been done using electromagnetically induced transparency based on these consideration in typical four level scheme [1,2] and a large phase shift (43°) has been recently observed by the light storage method in the atomic coherence medium [3]. A large Kerr phase shift can also be realized in an active Raman gain medium [4]. In this method, the signal wave travel with a superluminal group velocity and it suffers no attenuation or distortion because it is operated in a stimulated emission. Therefore, the phase gate can be realized with the fast response, inherently low loss, and continuous controllability in active Raman gain medium.

In this talk, we will show the first fast zero to π continuously controllable Kerr phase gate using a room temperature active Raman gain medium [5]. A large nonlinear phase shift of the probe light was demonstrated using a Mach-Zehnder interferometer by controlling the intensity and one-photon detuning of the phase-controlled light. Furthermore, we demonstrated the capability of digital phase gate by rapidly manipulating a digital encoded probe field with a digitally encoded phase-controlled field. We also demonstrated the experimental results that the probe light field is modulated by the standing wave field established in the medium by two counter propagating phase-controlled light beams [6]. This method can effectively decrease the phase-controlled light intensity in the experiment. Recently, we have further demonstrated a high-fidelity, weak-light controlled polarization phase gate based on a novel polarization selected Kerr phase shift technique [7]. We finally note that the fast Kerr scheme reported here may be implemented on the typical waveguide and/or photonic hollow fiber systems, which may find many applications in the telecommunications.

Reference:

[1] S. E. Harris, Phys. Today, 1997, 50, 36

[2] H. S. Kang, Y.F. Zhu, 2003, Phys. Rev. Lett. 91, 093601

[3] Y. F. Chen, C.Y. Wang, S.H. Wang, I.A. Yu, Phys. Rev. Lett., 2006, 96, 043603

[4] L. Deng, M.G. Payne, Phys. Rev. Lett., 2007, 98, 253902

[5] R.B. Li, L. Deng, E.W. Hagley, Phys. Rev. Lett., 2013, 110, 113902

[6] R.B. Li, L. Deng, E.W. Hagley, et.al, Opt. Lett., 2013, 38, 1373

[7] R.B. Li, C.J. Zhu, L. Deng, E.W. Hagley, submitted to Phys. Rev. Lett.