Wavefront shaping of spatially entangled photons
QUEST Center event:
Prof. Yaron Bromberg, Racah Institute of Physics at the Hebrew University
19/12/2018 - 12:00 - 13:00
Nano Center, 9th floor seminar room
n recent years, we are witnessing rapid developments of quantum technologies in a wide range of applications, including cryptography, spectroscopy, sensing, and imaging. 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 scattering 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 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 novel 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.