Beam Focusing and Reduction of Quantum Uncertainty in Width at the Few-Photon Level via Multi-Spatial-Mode Squeezing

Lida Zhang (张理达), G. S. Agarwal, and M. O. Scully

Phys. Rev. Lett. 122, 083601 – Published 28 February 2019

Abstract

We show for the first time that it is possible to realize laser beam focusing at the few-photon level in the four-wave-mixing process, and at the same time reduce the quantum uncertainty in width. The reduction in quantum uncertainty results directly from the strong suppression of local intensity fluctuations. This surprising effect of simultaneous focusing and reduction of width uncertainty is enabled by multi-spatial-mode (MSM) squeezing, and is not possible via any classical optical approach or single-spatial-mode squeezing. Our results open promising possibilities for quantum-enhanced imaging and metrology; as an example, the limit on the measurement of very small beam displacement can be enhanced within feasible experimental parameters because of beam focusing and the noiseless amplification in the MSM squeezing process.

Received 6 August 2018
Revised 4 December 2018

DOI:https://doi.org/10.1103/PhysRevLett.122.083601

Physics Subject Headings (PhySH)

Metrology Quantum fluctuations & noise Quantum information processing with continuous variables Quantum states of light Squeezing of quantum noise Third order nonlinear optical processes

Atomic, Molecular & OpticalNonlinear DynamicsQuantum Information, Science & Technology

Authors & Affiliations

Lida Zhang (张理达)^1,*, G. S. Agarwal^1,2, and M. O. Scully^1,3,4

¹Texas A&M University, College Station, Texas 77843, USA
²Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
³Baylor University, Waco, Texas 76798, USA
⁴Princeton University, Princeton, New Jersey 08544, USA