Department of Electrical and Electronic Engineering, Centre for Quantum Photonics, University of Bristol, Bristol BS8 1UB, United Kingdom.
Phys Rev Lett. 2013 Aug 30;111(9):093603. doi: 10.1103/PhysRevLett.111.093603. Epub 2013 Aug 29.
Entangled photons can be used to make measurements with an accuracy beyond that possible with classical light. While most implementations of quantum metrology have used states made up of a single color of photons, we show that entangled states of two colors can show supersensitivity to optical phase and path length by using a photonic crystal fiber source of photon pairs inside an interferometer. This setup is relatively simple and robust to experimental imperfections. We demonstrate sensitivity beyond the standard quantum limit and show superresolved interference fringes using entangled states of two, four, and six photons.
纠缠光子可用于进行超越经典光精度的测量。虽然量子计量学的大多数实现都使用由单个颜色的光子组成的状态，但我们通过使用干涉仪内光子对的光子晶体光纤源证明了两种颜色的纠缠态可以对光学相位和路径长度表现出超灵敏度。这种设置相对简单，对实验缺陷具有较强的鲁棒性。我们证明了超越标准量子极限的灵敏度，并使用两种、四种和六种光子的纠缠态显示了超分辨干涉条纹。
