A light‐guiding thin polyurethane film, doped with rhodamine 6G, is coated on the surface of a cylindrical glass rod and pumped with a pulsed Ne laser. A prism‐film coupler produces two output beams corresponding to clockwise and counterclockwise oscillations around the circumference of the rod. Unidirectional operation is obtained when one of the output beams is reflected back into itself. A maximum directionality ratio of 17 was measured.