Prajapati Nikunjkumar, Novikova Irina
Opt Lett. 2019 Dec 15;44(24):5921-5924. doi: 10.1364/OL.44.005921.
We propose and demonstrate a polarization-based truncated SU(1,1) interferometer that outputs the desired optical joint-quadrature of a two-mode squeezed vacuum field and allows its measurements using a single balanced homodyne detector. Using such a setup, we demonstrate up to ≈2 of quantum noise suppression below the shot-noise limit in intensity-difference and phase-sum joint-quadratures, and confirm entanglement between the two quantum fields. Our proposed technique results in a better balance between the two ports of the detector and, consequently, in better common noise suppression for differential measurements. As a result, we are able to observe flat joint-quadrature squeezing and entanglement at a wide range of detection frequencies: from several MHz (limited by the photodiode gain bandwidth) down to a few hundred Hz (limited by electronic noises).
我们提出并展示了一种基于偏振的截断SU(1,1)干涉仪，它输出双模压缩真空场所需的光学联合正交分量，并允许使用单个平衡零差探测器对其进行测量。利用这样的设置，我们在强度差和相位和联合正交分量中展示了高达约2倍的低于散粒噪声极限的量子噪声抑制，并证实了两个量子场之间的纠缠。我们提出的技术在探测器的两个端口之间实现了更好的平衡，因此在差分测量中实现了更好的共模噪声抑制。结果，我们能够在很宽的检测频率范围内观察到平坦的联合正交压缩和纠缠：从几兆赫兹（受光电二极管增益带宽限制）到几百赫兹（受电子噪声限制）。
