“It has to resonate.” Sagnac’s counter-rotating beams of light are analogous to beams in a linear cavity. If the turntable rotates clockwise, the beam traveling clockwise has farther to go ...

In essence, calcite splits a beam of light into two dots based on polarization. By aligning filters and rotating angles, you can observe how light behaves when forced into ‘choices’.

Campaigners fear that altering the mechanism controlling the rotating light could harm the ... produces a "beautiful" and ...