Reaffirmed 2022

NATIONAL FOREWORD

This Indian Standard (Part 3) (First Revision) which is identical with ISO/TR 11146-3 : 2004 ‘Lasers and laser-related equipment — Test methods for laser beam widths, divergence angles and beam propagation ratios — Part 3: Intrinsic and geometrical laser beam classification, propagation and details of test methods’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Educational Instruments and Equipment Sectional Committee and approval of the Production and General Engineering Division Council.

This standard was originally published as IS 14820 : 2000 which was an adoption of ISO 11146 : 1999. Now, ISO 11146 is published in three parts. This revision has been taken up to align with the latest version of ISO 11146. The other parts of this standard are:

Part 1 Stigmatic and simple astigmatic beams

Part 2 General astigmatic beams

The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain terminology and conventions are, however, not identical to those used in the Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice to use a full point (.) as the decimal marker.