AUTHOR=Puentes Graciana , Banerji Anindya 

TITLE=Generation of High-Order Vortex States From Two-Mode Squeezed States

JOURNAL=Frontiers in Physics

VOLUME=Volume 9 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2021.690721

DOI=10.3389/fphy.2021.690721

ISSN=2296-424X

ABSTRACT=We report a scheme for generation of high-order \textbf{quadrature} vortex states using two-mode photon-number squeezed states, generated via the non-linear process of Spontaneous Parametric Down Conversion. 
By applying a parametric rotation in the quadratures $(\hat{X},\hat{Y})$, using a $\phi$ converter, the Gaussian profile of the photon-number squeezed input state can be mapped into a superposition of Laguerre-Gauss modes  in the quadratures  with $N$ vortices or singularities,
for an input state containing \textbf{$2N$} photons, thus mapping photon-number fluctuations to interference effects in the quadratures. Our scheme has the potential to improve measurement sensitivity beyond the Standard uantum Limit ( SQL $\propto \sqrt{N}$), by exploiting the advantages of optical vortices, such as high dimensionality or topological properties, for applications requiring reduced uncertainty, such as quantum cryptography, quantum metrology and sensing.