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Updated: Jul 11, 2026

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Spectral density matrix of a single photon measured
Wojciech Wasilewski1, Piotr Kolenderski, Robert Frankowski
1Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Toruń, Poland.
Abstract:
We propose and demonstrate a method for measuring the spectral density matrix of a single photon pulse. The method is based on registering Hong-Ou-Mandel interference between a photon to be measured and a pair of attenuated and suitably delayed laser pulses described by a known spectral amplitude. The density matrix is retrieved from a two-dimensional interferogram of coincidence counts. The method has been implemented for a type-I down-conversion source, pumped by ultrashort laser pulses. The experimental results agree well with a theoretical model which takes into account the temporal as well as spatial effects in the source.
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