In our paper, we demonstrate the coldest spontaneous parametric down-conversion (SPDC) experiment that was done so far. We show that SPDC in nonlinear waveguides, which is typically performed under ambient conditions, remains functional when it is operated at about 4 K. We investigate the source performance metrics and the spectral properties of our SPDC source. Our results indicate that cryogenics principally affect the modes which the SPDC populate rather than the quantum states themselves. These findings are crucial for combining SPDC with other cryogenic quantum technologies in a single device.
The paper is available at:
https://doi.org/10.1364/OPTICA.445576
A press article can be found at:
https://www.uni-paderborn.de/nachricht/97230
For a short video about the paper click here.
