Water as a mirror?
Water puts the “magnetic” back in “electromagnetic.” In nature’s schematic above, a standing light wave with magnetic (blue) and electric (red) field peaks is generated in an optical photonic cavity, it acts as a resonator. As the light bounces between two reflection points that act like mirrors it transfers information from the quantum spin of particles to orbital angular momentum. This is how lasers can be tuned and how we can increase the base quantum spin number of photons. Normally photons have a quantum spin number of one.