High-order orbital angular momentum modes in bright squeezed vacuum states of light

• Applicant: Professorin Dr. Polina Sharapova
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 413296026

Helically-phased light beams attract more and more interest due to the orbital angular momentum that they carry. The (almost) unlimited value of leads to an unrestricted range of basis states, so-called orbital angular momentum modes, which may enable larger-alphabet quantum key distribution and provide high-dimensional quantum information resistant to eavesdropping. Orbital angular momentum modes are very promising for transmitting information over large distances, designing novel imaging systems and empowering quantum cryptography opportunities. Moreover, orbital angular momentum modes can be used in high-resolution and high-sensitivity measurements and for the optical manipulation of particles through light-matter interaction. To improve the quantum capacity of orbital angular momentum modes even further, one could use quantum light with huge photon numbers per mode. A promising candidate for that is the bright squeezed vacuum. Bright squeezed vacuum, is a macroscopic non-classical state of light that can be obtained via high-gain parametric-down-conversion or four-wave-mixing, and has a very broad photon-number distribution with very high photon numbers. Unlike displaced squeezed-light states, bright squeezed vacuum consists only of quantum noise and has strong photon-number correlations, leading to the reduction of noise below the shot-noise level as well as to quadrature squeezing. Such features of bright squeezed vacuum make it very attractive for various applications such as quantum imaging and sensitive metrology, quantum optomechanics, gravitational wave detecting, and nonlinear optics with quantum light. The proposed work focuses on the theoretical description of physical properties of so far unexplored high-order orbital angular momentum modes in bright squeezed vacuum, their preparation and sorting. All schemes for preparation and sorting of such modes will be based on the two- and three-crystal configuration with using an additional optical elements and non-Gaussian pump beams. The description of the selected orbital angular momentum modes will be performed from the point of view of Schmidt modes. The methods for preparation of a single orbital angular momentum mode with high quadrature squeezing and photon-number-correlated pairs of orbital angular momentum modes with noise reduction below the shot-noise level will be suggested. Simultaneously, we plan to suggest and calculate schemes of applying high-order orbital angular momentum modes for the rotation of mechanical objects and for passing strong correlations from the light subsystem to the mechanical one, for testing non-symmetrical absorption spectra of atoms, molecules, quantum dots, for testing the chirality of different objects, and for very sensitive phase measurements. Moreover, a theoretical description of orbital angular momentum modes in bright squeezed vacuum including time-ordering effects will be developed.

• DFG Programme: Research Grants