Joint spectrum of photon pairs measured by coincidence Fourier spectroscopy
Wojciech Wasilewski, Piotr Wasylczyk, Piotr Kolenderski, Konrad Banaszek, Czeslaw Radzewicz · Optics Letters · 2006
We propose and demonstrate a method for measuring the joint spectrum of photon pairs via Fourier spectroscopy. The biphoton spectral intensity is computed from a two-dimensional interferogram of coincidence counts. The method has been implemented for a type-I downconversion source using a pair of common-path Mach-Zehnder interferometers based on Soleil compensators. The experimental results agree well with calculated frequency correlations that take into account the effects of coupling into single-mode fibers. The Fourier method is advantageous over scanning spectrometry when detectors exhibit high dark count rates leading to dominant additive noise.