Probing ultra-fast dephasing via entangled photon pairs

We demonstrate how the Hong-Ou-Mandel (HOM) interference with polarization -entangled photons can be used to probe ultrafast dephasing. We can infer the optical properties like the real and imaginary parts of the complex susceptibility of the medium from changes in the position and the shape of the HOM dip. From the shift of the HOM dip, we are able to measure 22 fs dephasing time using a continuous-wave (CW) laser even with optical loss > 97 %, while the HOM dip visibility is maintained at 92.3 % (which can be as high as 96.7 %). The experimental observations, which are explained in terms of a rigorous theoretical model, demonstrate the utility of HOM interference in probing ultrafast dephasing.

Automated summary

This paper demonstrates how the Hong-Ou-Mandel interference with polarization-entangled photons can be used to probe ultrafast dephasing. The optical properties of the medium can be inferred from changes in the position and shape of the HOM dip. Experimental observations show that even with high optical loss, a dephasing time of 22 fs can be measured using a continuous-wave laser, while maintaining a high HOM dip visibility.