Generation of UV-Vis correlated photon pairs using PP-LaBGeO5

The SHG and SPDC output of a periodically poled bulk LBGO crystal is measured. The SHG efficiency is measured to be (3.52 +/- 0.04) x 10^-3 %/W. The SPDC output is temporally characterized by a Hanbury-Brown-Twiss interferometer; a maximum CAR of 244 and pair generation rate of (1.45 +/- 0.47) x 10^6 pairs s^-1 mW^-1 is measured. An EMICCD spectrometer is used to measure the spectral characteristics of the PP-LBGO source. Of the four gratings tested, one operational grating (poling period = 2.10 um) of the PP-LBGO device outputs a temperature tunable spectrum of entangled photon pairs centered at 532 nm with signal and idler photons being tunable from 507 to 556 nm, respectively. The work paves the way for future waveguided entangled photon sources reaching UV wavelengths using periodic poling.