What Happens When You Squeeze Light? A Quantum Explanation

This 12-minute educational video explores the fascinating quantum physics behind light diffraction through narrow openings. Discover why squeezing light through a small gap causes it to spread out, revealing fundamental principles of quantum mechanics. The explanation begins with a demonstration of a laser beam passing through a narrow slit, showing how instead of simply creating a thinner beam, it produces a distinctive diffraction pattern. Learn how this phenomenon persists even when light intensity is reduced to single photons, demonstrating quantum probability rather than classical wave interference. Connect this spreading effect to photon momentum using geometry and the de Broglie relation, understanding how spatial confinement creates momentum uncertainty that increases as the slit narrows. By the end, derive a mathematical expression of Heisenberg's uncertainty principle, transforming a common classroom demonstration into a profound illustration of one of physics' most fundamental limits.