Characterization of Broadband Spontaneous Parametric Down-Conversion in Periodically Poled Materials

Spontaneous parametric down-conversion (SPDC) is one of the most important sources for entangled or correlated photon pairs, which are the foundation of the emerging fields of quantum-optical imaging and spectroscopy. Using periodically poled materials as an SPDC-source allows broad emission spectra in widely tunable wavelength ranges in an efficient and walk-off-free process. For applications that employ nonlinear interference setups [1,2], maximum interferometric contrast is only achieved when signal and idler modes are overlapped precisely in the second crystal. Thus, accurate knowledge of the spectral-angular characteristic of SPDC is crucial for designing such devices.