We demonstrate a two phase-grating, multi-beam neutron interferometer by using a modified Ronchi setup in a far-field regime. The functionality of the interferometer is based on the universal moiré effect that was recently implemented for X-ray phase-contrast imaging in the far-field regime.Interference fringes were achieved with monochromatic, bichromatic, and polychromatic neutron beams; for both continuous and pulsed beams. This far-field neutron interferometry allows for the utilization of the full neutron flux for precise measurements of potential gradients, and expands neutron phase-contrast imaging techniques to more intense polycromatic neutron beams. *

We proposed and demonstrated a simple but deterministic scheme for generating polarization-entangled photon pairs at telecommunication wavelengths with type-II quasi-phase-matched spontaneous parametric down-conversion (QPM-SPDC) having two poling periods. We fabricated a LiNbO3 crystal having two poling periods so as to generate entangled photons at two wavelengths, i.e., 1506 nm and 1594 nm. We characterized the two-photon polarization state with state tomography and confirmed that the state was highly entangled.

Development of efficient and well-controlled nonclassical photon sources is one of the keys in the quantum information and communication technology. We present our recent activities to develop advanced sources of photon pairs having controlled frequency correlation, by use of quasi-phase matching (QPM) and extended phase-matching (EPM). First, we present the generation of polarization and frequency entangled photons using QPM having two poling periods. We also demonstrate the photon pair generation with controlled frequency correlation and its application to making heralded single photons with intrinsically pure spectrotemporal modes.