Generation and application of strongly squeezed vacuum states of light

光的压缩真空状态已被用于各种原理证明实验，以减少光子计数噪声（散粒噪声）。压缩光在量子计量中的首次长期应用已经在德国汉诺威的GEO600引力波探测器上进行了两年多。这次成功的压缩光应用证明了它的普遍重要性，但也表明了在不那么复杂、因此更可靠的压缩光源设置中产生更高的压缩水平的需求。本课题提出在一种新型驻波双共振压缩腔中产生波长为1064nm的光的压缩真空态。这种拓扑结构有望提供前所未有的高压缩水平，范围从音频频带频率到mhz边带频率，同时显著减少了产生强压缩所需的光学元件数量。因此，提出的压缩光源的高可靠性似乎是现实的。此外，我们提出了将产生的强压缩态应用于非经典激光干涉测量的两个重要方面。首先，利用强压缩态直接测量光电二极管的绝对量子效率。这种基于非经典光的测量技术的精度将超过经典（相对）测量精度，并将为在许多应用中实现高检测效率的压缩光提供重要见解。其次，将首次利用压缩光进行超越量子极限的非经典光增强激光功率稳定实验。

Squeezed vacuum states of light have been used in a variety of proof-of-principle experiments to reduce the photon counting noise (shot noise). The first long-term application of squeezed-light in quantum metrology has been ongoing since more than two years now in the gravitational wave detector GEO600, Hannover, Germany. This successful squeezed-light application has proven it´s general importance but also indicates the demand for higher generated squeezing levels produced in a less complex and therefore more reliable squeezed-light source setup.This project proposes the generation of squeezed vacuum states of light at a wavelength of 1064nm in a novel standing-wave doubly-resonant squeezing resonator. This topology is expected to provide unprecedented high squeezing levels ranging from audio-band frequencies up to MHz-sideband frequencies with a significantly reduced number of optical components required for the strong squeezing generation. As a consequence, a high reliability of the proposed squeezed light source seems realistic. Furthermore, we propose the application of the generated strongly squeezed states to two important aspects of non-classical laser interferometry. Firstly, the strongly squeezed states will be employed to determine the absolute quantum efficiency of photo diodes in a direct measurement. The precision of this measurement technique based non-classical light will beat the classical (relative) measurement accuracy and will give important insights for a high detection efficiency of squeezed light in many applications. Secondly, squeezed light will be used to demonstrate a non-classical light enhanced laser power stabilization experiment surpassing the quantum limit for the first time.