Experimental Test of Bell's Inequalities Using Time- Varying Analyzers

TLDR

The experiment uses acousto‑optical switches followed by two linear polarizers in each arm, operating at incommensurate ~50 MHz frequencies to rapidly alternate between two polarizer orientations within the photon transit time. Measured photon polarization correlations agree with quantum mechanics and violate Bell's inequalities by five standard deviations.

Abstract

Correlations of linear polarizations of pairs of photons have been measured with time-varying analyzers. The analyzer in each leg of the apparatus is an acousto-optical switch followed by two linear polarizers. The switches operate at incommensurate frequencies near 50 MHz. Each analyzer amounts to a polarizer which jumps between two orientations in a time short compared with the photon transit time. The results are in good agreement with quantum mechanical predictions but violate Bell's inequalities by 5 standard deviations.