Nobel Laureate and Optica Emeritus, John F. Clauser is an American experimental and theoretical physicist. He is best known for his contributions to the foundations of quantum mechanics, in particular for the Clauser-Horne-Shimony-Holt (CHSH) inequality, the first experimental proof that non-local quantum entanglement is real (Freedman-Clauser), and for the formulation of the theory of Local Realism (Clauser-Horne).

In 1987-1991 he proposed (and patented) atom interferometers as useful ultra-sensitive inertial and gravity sensors. In 1992, with Matthias Reinsch, Clauser first deduced the number-theoretic properties of the fractional Talbot effect and invented the Talbot-Lau interferometer.

From 1990-1997, with Shifang Li, Clauser first used Talbot-Lau interferometry to build an atom interferometer. In 1998 he invented and patented the use of the Talbot-Lau interferometry for "Ultrahigh Resolution Interferometric X-ray Imaging." This invention, in turn, allows x-ray phase-contrast medical imaging of soft tissue.

Clauser was awarded the Reality Foundation Prize in 1982, the Wolf Prize in 2010, and the 2011 Thompson-Reuters Citation Laureate in Physics. Learn more: John Clauser.

On 4 October 2022, Clauser was awarded the Nobel Prize in Physics, along with Alain Aspect and Anton Zeilinger, for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science.