Modulating quantum fluctuations of scattered light in disordered media via wavefront shaping

Abstract

After multiple scattering of quadrature-squeezed lights in a disordered medium, the quadrature amplitudes of the scattered modes present an excess noise above the shot-noise level [Opt. Expr. 14, 6919 (2006)]. A natural question is raised whether there exists a method of suppressing the quadrature fluctuation of the output mode. The answer is affirmative. In this work, we prove that wavefront shaping is a promising method to reduce the quantum noise of quadrature amplitudes of the scattered modes. This reduction is owing to the destructive interference of quantum noise. Specifically, when the single-mode squeezed states are considered as inputs, the quantum fluctuation can always be reduced, even below the shot-noise level. These results may have potential applications in quantum information processing, for instance, sub-wavelength imaging using the scattering superlens with squeezed-state sources.

Scattering-lens based quantum imaging beyond shot noise

“…After multiple scattering, the scattered mode b 48 can be written as where ( ) denote the annihilation operator of the incident modes ( ) and obey the commutation relation ( ). The transmission and reflection coefficients and , subject to a constraint 13 , can be approximately regarded as complex Gaussian random variables 50 . Accordingly, and where ( ) is indeed uniformly distributed in the interval [ ] while and are the variables of Rayleigh distribution.…”

“…In the presence of wavefront shaping, the scattered light can be directed towards a focus in any desired output mode with a scattering lens 37 . Mathematically, the related input-output relation 13 can be characterized as where the superscript w denotes wavefront shaping. In contrast to Eq.…”

“…The transmission and reflection coefficients t a ′ b and r b ′ b , subject to a constraint 13 When the beams are injected, without the wavefront shaping in (a), the scattering lens separates the light into different optical channels randomly. As a result, the output presents a speckle pattern.…”

“…Although this method provides a high resolution with a coherent-state input, the performance of imaging is still shot-noise-limited due to the shot noise of the coherent state (in fact, the performance of imaging is related to the quantum noise of the focused beam illuminating the object. When the coherent states are considered as input, the focused beam is still a coherent state 13 ). To circumvent this problem, one possible way is to reduce the shot noise.…”

“…By scanning the focus and collecting the light behind the object, the image of the object can be obtained. state 13 ). To circumvent this problem, one possible way is to reduce the shot noise.…”