Expérimental
We propose to study an interferometer including two optical frequency conversion crystals (i.e. twin photon generators), and compare the key parameters under the quantum and classical regimes. The main asset of this non-linear interferometer is to be able to probe an object in the infrared (like a gas showing strong absorption lines), while detecting all the photons in the visible spectrum, where photodetectors are very sensitive. The internship will consist in using the current interferometer, which emits at around 1 µm, and compare the quantum and classical regimes, with and without a probed object. The interferometer can then be modified to emit around 2 µm. The internship will provide an opportunity to perfect laser techniques, non-linear optics (frequency conversion) and quantum optics (correlation measurements, coincidences, etc.).