Excess-noise cancellation for quadrature-squeezed light through scattering media via two-sided wavefront shaping

In diversified optical applications, such as optical imaging and optical metrology, it is evidently significant to pursue low quantum fluctuations of light to promise the enhancement of measurement precision. Recently, it has been demonstrated that the technique of wavefront shaping provides an effective avenue to suppress the excess quantum noise of quadrature-squeezed light through a disordered medium in the presence of one-sided illumination. Nevertheless, the minimum suppressed noise is still above the initial squeezed noise level. Inspired by two-sided modulation enabling novel optical phenomena, we propose an alternative noise-reduction scheme combining two-sided illumination with wavefront shaping. It is clarified that our approach is able to further reduce the excess quantum fluctuation. The exact condition for the reduced noise to reach below the standard quantum limit is given. Intriguingly, the excess noise can be fully erased in certain case. Therefore, our scheme paves another way for elimination of the excess noise induced by multiple scattering in disordered media. •Method combines bilateral illumination with wavefront shaping for noise reduction.•Achieves lower quantum noise levels, even below the shot noise.•Two-sided wavefront shaping surpasses one-sided one in noise suppression.•Excess noise can be completely eliminated in non-amplifying media.