Generation and application of strongly squeezed vacuum states of light

• Applicant: Dr. Henning Vahlbruch
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 269638877

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.

• DFG Programme: Research Grants