We characterize a pp-KTP crystal designed to produce pure single mode squeezed vacuum at 1570 nm. Measurements show a raw (corrected) Hong-Ou-Mandel interference with 86 % (90 %) visibility and a circular joint spectral probability distribution with a Schmidt number of 1.08 when spectral filtering with 8.6 nm bandwidth is applied. We use superconducting nanowire single photon detectors to measure the joint spectral probability distribution, and use photon-number resolving transition edge sensors to perform Hong-Ou-Mandel interference experiments. Both types of detectors are used to measure second-order correlations: the nanowire detectors with time-domain histogramming, and the transition edge sensors by measuring photon number statistics. Results from these two very different techniques are in good agreement.
Citation: Optics Express
Pub Type: Journals
homodyne detection, optical cat states, periodic poling, quantum information, squeezing, transition edge sensors