Laser Beam Divergence Measurement

1414 laser beam diagnostics 1991.

Laser beam divergence measurement.

The divergence of a laser beam can be calculated if the beam diameter d 1 and d 2 at two separate distances are known. Standard for the measurement of beam widths beam divergence and propagation factors proposal for a working draft iso tc 172 sc 9 wg 1 april 29 1992. The beam divergence of a laser beam is a measure for how fast the beam expands far from the beam waist i e in the so called far field. The focal length divergence method provides a means for finding the far field beam divergence at any point in the beam propagation path.

This definition yields a divergence half angle. Simple beam propagation measurements on ion lasers spie vol. Dataray offers a full range of iso 11146 compliant beam profilers both camera and scanning slit based which provide multiple methods of measuring beam divergence. The focal length divergence measurement method the focal length divergence measurement method is based upon the beam width of a focused beam s spot size and the focal length of the focusing optic.

The m 2 factor compares the actual shape of the beam to that of an ideal gaussian beam. In electromagnetics especially in optics beam divergence is an angular measure of the increase in beam diameter or radius with distance from the optical aperture or antenna aperture from which the beam emerges. You know that bell shaped curve telling you that most of the beam energy is located at the center of the beam along the propagation axis. Beam divergence is defined by the full angle.

The term is relevant only in the far field away from any focus of the beam practically speaking however the far field can commence physically close to the radiating aperture. The beam divergence of a laser beam is a measure for how fast the beam expands far from the beam waist. In laser diodes beam divergence is specified with two values because of the presence of astigmatism see diodes vs. The beam divergence defines how much the beam spreads out over increasing distance from the optical aperture.

Beam divergence is defined in the far field where the beam divergence is constant. For an electromagnetic beam beam divergence is the angular measure of the increase in the radius or diameter with distance from the optical aperture as the beam emerges. A low beam divergence can be important for applications such as pointing or free space optical communications. Laser beam divergence measurement is all about beam size.

In this case the orientation of the beam divergence needs to be.