Nonlinear Physics Seminar:"Tailoring the shape of entangled photons"

Wed, 22/01/2020 - 12:00 to 13:30

Danciger B building, Seminar room
Lecturer: Dr Yaron Bromberg from HUJI
In recent years, we are witnessing rapid developments of quantum technologies in a wide range of applications. However, the implementation of quantum technologies in real-world scenarios is still held back, mostly due to the fragile nature of quantum states of light. In many applications, photons are sent through a random medium, such as the earth’s atmosphere, forming speckle patterns. For classical light, recent breakthroughs in wavefront shaping have opened the door for fast compensation of scattering, by precisely tailoring the optical wavefront. However, applying these methods to quantum light is extremely challenging due to the weak measured signals. Here, we extend wavefront shaping to the quantum domain. We show that in the high spatial entanglement regime of spontaneous parametric down conversion (SPDC), compensating for the scattering of entangled photons can be achieved by shaping the incident pump beam. Surprisingly, the two-photon speckle pattern is identical to that of the pump beam, thus allowing the pump beam intensity to be used as feedback for the optimization. Using this method, we compensate for the scattering of entangled SPDC light in real-time and achieve enhancements comparable with those obtained for wavefront shaping of classical light.