Four-wave mixing in fibers for bright squeezed vacuum

该项目的目的是通过多光子（>100）的四波混频（FWM）产生光的纠缠态。光的量子态在SU（1，1）干涉测量中得到应用，产生量子增强的灵敏度。在计划的实验中，强泵浦光沿合适的光子晶体光纤沿着传播。四波混频将导致两个泵浦光子自发转换为另外两个光子，信号和闲频光束，由它们的频率定义。如果该过程具有非常高的增益并且不是完全自发的，而是通过注入信号来播种，则可以在光纤输出处实现高光子数，从而保持信号和闲频之间的强量子相关性。光的量子态被称为“明亮压缩真空”[1]。如果将这种光源用于干涉测量，则可以达到干涉仪的海森堡极限，这是一种非经典极限。因此，在项目的第二阶段，这种光将用于干涉测量，其中反向四波混频相互作用在产生的信号和闲频光束之间产生非线性干涉。与线性经典干涉仪相比，灵敏度的增加与干涉仪中光子数的平方根成比例，从而超过了干涉仪的经典噪声极限。 该项目涉及脉冲和连续激光、光纤、光谱和单光子计数。该项目将与德国马克斯普朗克光研究所的Chekhova教授合作并进行知识交流。[1]I.N. Agafonov、M.V. Chekhova和G. Leuchs，双色明亮压缩真空。Phys. Rev. A 82，011801（R）（2010）。

Four-wave mixing in fibers for bright squeezed vacuumThe aim of the project is to produce entangled states of light by four-wave mixing (FWM) with many photons (>100). The quantum states of light find applications in SU(1,1) interferometry, which yields a quantum enhanced sensitivity.In the planned experiment, a strong pump light is propagated along a suitable photonic-crystal fiber. The FWM will lead to the spontaneous conversion of two pump photons to two other photons, the signal and idler beams, defined by their frequency. If the process has very high gain and is not entirely spontaneous, but seeded by injecting a signal, high photon numbers can be achieved at the fiber output, maintaining the strong quantum correlations between signal and idler. The quantum state of light is referred to as 'bright squeezed vacuum' [1]. If this light source is used in interferometry, the Heisenberg limit of interferometers, which is a nonclassical limit, can be reached.Thus in a second stage of the project, this light will be used in interferometry, in which the reverse FWM interaction creates nonlinear interference between the produced signal and idler beams. The increase in sensitivity compared to a linear classical interferometer scales as the square root of the photon number in the interferometer, beating the classical noise limits of interferometers. The project involves pulsed as well as continuous lasers, fiber optics, spectrometry, and single photon counting.The project will be carried out in collaboration and intellectual exchange with Prof. Chekhova at the Max Planck Institute of Light, Germany.[1] I.N. Agafonov, M.V. Chekhova, and G. Leuchs, Two-Color Bright Squeezed Vacuum. Phys. Rev. A 82, 011801(R) (2010).