We report the experimental realization of squeezed quantum states of light, tailored for new applications in quantum communication and metrology. Squeezed states in a broad Fourier frequency band down to 1 Hz has been observed for the first time. Nonclassical properties of light in such a low frequency band is required for high efficiency quantum information storage in electromagnetically induced transparency (EIT) media. The states observed also cover the frequency band of ultra-high precision laser interferometers for gravitational wave detection and can be used to reach the regime of quantum non-demolition interferometry. And furthermore, they cover the frequencies of motions of heavily macroscopic objects and might therefore support the attempts to observe entanglement in our macroscopic world.
@article{arxiv.0707.2845,
title = {Quantum engineering of squeezed states for quantum communication and metrology},
author = {Henning Vahlbruch and Simon Chelkowski and Karsten Danzmann and Roman Schnabel},
journal= {arXiv preprint arXiv:0707.2845},
year = {2007}
}