Method for testing light collimation based on talbot effect

The optical test and optical instruments calibrating often use the collimated beam, so the research of light collimation is of great significance. Lots of new techniques have been proposed. Based on Talbot effect, a method for testing light collimation is proposed that the collimation of laser beam checked by measuring the obliquity of Moire fringe of twin-grating. By improving the previous testing method and discussing impact on the precision of the method, the precision was estimated theoretically. The result shows that the technique is very simple and has a high precision.