Experimental requirements for entangled two-photon spectroscopy

Coherently controlling the spectral properties of energy-entangled photons is a key component of future entangled two-photon spectroscopy schemes that are expected to provide advantages with respect to classical methods. We present here an experimental setup based on a grating compressor. It allows for the spectral shaping of entangled photons with a sevenfold increase in resolution, compared to previous setups with a prism compressor. We evaluate the performances of the shaper by detecting sum frequency generation in a nonlinear crystal with both classical pulses and entangled photon pairs. The efficiency of both processes is experimentally compared and is in accordance with a simple model relating the classical and entangled two-photon absorption coefficients. Finally, the entangled two-photon shaping capability is demonstrated by implementing an interferometric transfer function.

Automated summary

Researchers have successfully demonstrated spectral shaping of energy-entangled photons using a grating compressor, achieving a sevenfold increase in resolution compared to previous prism compressor setups. Efficiency comparison of sum frequency generation with classical pulses and entangled photon pairs aligns with a simple model relating classical and entangled two-photon absorption coefficients. The capability of shaping entangled two-photon spectra was shown through implementation of an interferometric transfer function.