Two-photon quantum interference for an undergraduate lab
Alexei Ourjoumtsev, M. C. Dheur, Thierry Avignon, Lionel Jacubowiez · European Journal of Physics · 2015
We present a simple setup allowing undergraduate students to reproduce the Hong–Ou–Mandel experiment during a half-day labwork session and observe the coalescence of two indistinguishable photons merging on a balanced beamsplitter. This two-photon interference effect, fundamentally related to the bosonic character of the photons, is commonly used in the fields of quantum communication and computing to test the indistinguishability of two single-photon wavepackets. The setup makes use of very few optical elements and requires little alignement that can be performed by students themselves. It allows them to gather essential experimental skills related to parametric crystals, fibre optics and single-photon detection, and to transpose abstract concepts of quantum physics to a hands-on experiment in the lab.