Schematic diagram of the hollow conic beam generator. A
conventional cylindrical rod is used as a hollow conic beam generator
by illuminating a laser beam inclined to the axis of the rod. Half of
the conic beam is formed by the reflection at the surface of the
cylindrical rod, and the opposite side of the conic beam by its transmission.
The angle represents the angle between the ray axis of
the laser beam and the axis of the cylindrical rod. b Scattered
pattern of the hollow conic beam on the observing plane perpendicular
to the axis of the cylindrical rod.