New High-Intensity Source of Polarization-Entangled Photon Pairs by Paul G. Kwiat and others 2026-10-20
Physical Review Letters 75, 4337–4341. Primary experimental paper.
Publisher: doi.org/10.1103/PhysRevLett.75.4337
The experiment uses noncollinear type-II down-conversion, birefringent walk-off compensation and polarization-dependent coincidence measurements.