Quadrature squeezing of 10 4 spatial modes via manipulation of diffraction

Abstract

We propose a general and feasible approach to realize a large number of squeezed spatial modes. This is achieved by manipulation of paraxial diffraction such that the critical wave components with most significant squeezing contribute in-phase to the spatial squeezing. As an example, we then demonstrate that it is possible to achieve localized squeezing of $\ensuremath{\sim}\ensuremath{-}1.51\phantom{\rule{3.33333pt}{0ex}}\text{dB}$ at an area ${10}^{2}\phantom{\rule{3.33333pt}{0ex}}\ensuremath{\mu}{\text{m}}^{2}$ within a homogeneously squeezed spatial regime of ${w}_{p}=1\phantom{\rule{3.33333pt}{0ex}}{\text{mm}}^{2}$ using four-wave mixing (FWM) based on current experimental settings, corresponding to approximately ${10}^{4}$ squeezed spatial modes, which is $>{10}^{2}$ larger in number of squeezed modes and also $\ensuremath{\sim}6$ times stronger in squeezing as compared to that obtained in the state-of-the-art experiment. We also show that the obtained extremely localized squeezed light can be directly applied to enhance the signal-to-noise ratio in quantum imaging of weakly absorbing objects by a factor of $\ensuremath{\sim}3.5$ at a spatial resolution of $d\ensuremath{\sim}1\phantom{\rule{3.33333pt}{0ex}}\text{mm}$ where $d$ is the detector size.