Abstract: A beam of coherent light is generated in a 360.degree. pattern about a central axis perpendicular to the beam, either outwardly from or inwardly toward the axis, without requiring moving parts. The beam is introduced into the space between concentric, cylindrical surfaces, both reflective to some extent, but one more highly reflective than the other, with respect to the wavelength of the beam. After multiple reflections between the surfaces, the beam passes through the less reflective surface about the entire 360.degree. circumference thereof. In a first embodiment the beam is generated by a conventional laser, or the like, and directed along an axis which perpendicularly intersects the axis of a hollow tube having external and internal surfaces which provide the aforementioned multiple reflections.