What is ISO 11146-2 about?
ISO 11146-2 specifies methods for measuring beam widths (diameter), divergence angles and beam propagation ratios of laser beams. ISO 11146-2 applies to general astigmatic beams or unknown types of beams.
Within ISO 11146-2, the description of laser beams is accomplished using the second-order moments of the Wigner distribution rather than physical quantities such as beam widths and divergence angles. However, these physical quantities are closely related to the second-order moments of the Wigner distribution.
Who is ISO 11146-2 for?
ISO 11146-2 is useful for test methods of laser and laser-related equipment:
- Manufacturers of laser and laser-related equipment
- Research and development teams
- Quality control personnel
Why should you use ISO 11146-2?
The theoretical description of beam characterization and propagation, as well as the classification of laser beams, is given in ISO 11146-2, which is a Technical Report. The procedures for background subtraction and offset correction are also given in ISO 11146-2.
The measurement methods for stigmatic and simple astigmatic beams while ISO 11146-2 deals with the measurement procedures for general astigmatic beams. ISO 11146-2 applies to beams of unknown type.
Three alternative methods for beam width measurement and their correlation with the method used in ISO 11146-2 are described. These methods are:
- Variable aperture method
- Moving knife-edge method
- Moving slit method.
These methods described in ISO 11146-2 help you to evaluate the quality of your laser equipment.
What’s changed since the last update?
BS EN ISO 11146-2:2021 supersedes BS EN ISO 11146-2:2005. BS EN ISO 11146-2:2021 includes some technical changes concerning BS EN ISO 11146-2:2005. These include:
- The terms and definitions were harmonized with the new ISO 11145.
- The "principal axes" were defined more thoroughly and named as x' and y'. Quantities related to the principal axes coordinate system refer to this definition and use x’ and y' in their indices.
- The requirements for the integration range for the determination of the second-order moments have been relaxed.

