Quantum light in complex media and its applications

Gerard Nienhuis, Steven Habraken

Baptiste Courme, Chloé Vernière, Malo Joly +3 more

Optimization approaches are ubiquitous in physics. In optics, they are key to manipulating light through complex media, enabling applications ranging from imaging to photonic simulators. In most demonstrations, however, the optimization process is implemented using classical coherent light, leading to a purely classical solution. Here, we introduce the concept of optical non-classical optimization in complex media. We experimentally demonstrate the control and refocusing of non-classical light—namely, entangled photon pairs—through a scattering medium by directly optimizing the output coincidence rate. Importantly, these optimal solutions cannot be obtained with classical light and do not result in a focus for classical light; this is a result of entanglement in the input state. This genuinely non-classical optimization method promises advances in quantum imaging, communication, and optical simulations with non-classical light.

Ronen Shekel, Ohad Lib, Sébastien M. Popoff +1 more

When light propagates through complex media, its output spatial distribution is highly sensitive to its wavelength. This fundamentally limits the bandwidth of applications ranging from imaging to communication. Here, we demonstrate analytically and numerically that the spatial correlations of hyper-entangled photon pairs, simultaneously entangled spatially and spectrally, remain stable across a broad bandwidth: The chromatic modal dispersion experienced by one photon is canceled to first order by its spectrally anti-correlated twin, defining a "two-photon bandwidth" that can far exceed its classical counterpart. We illustrate this modal dispersion cancellation in multimode fibers, thin diffusers and blazed gratings, and demonstrate its utility for broadband wavefront shaping of quantum states. These findings advance our fundamental understanding of quantum light in complex media with applications in quantum imaging, communication, and sensing.

S. Chua

Baptiste Courme, Chloé Vernière, Malo Joly +3 more

Optimization approaches are ubiquitous in physics. In optics, they are key to manipulating light through complex media, enabling applications ranging from imaging to photonic simulators. In most demonstrations, however, the optimization process is implemented using classical coherent light, leading to a purely classical solution. Here we introduce the concept of optical non-classical optimization in complex media. We experimentally demonstrate the control and refocusing of non-classical light -- namely, entangled photon pairs -- through a scattering medium by directly optimizing the output coincidence rate. The optimal solutions found with this approach differ from those obtained using classical optimization, a result of entanglement in the input state. Beyond imaging, this genuinely non-classical optimization method has potential to tackle complex problems, as we show by simulating a spin-glass model with multi-spin interactions.

Hakan E. Türeci, Dmitry N. Chigrin