Engineering comparison between CCD and the variable aperture methods for measuring the divergence angle of laser beam

Laser beam divergence angle of laser beams is an important parameter in the laser characterization. There are many methods of beam divergence determination. The most common way is to use a device based on CCD described in the International Standard ISO11146-1 "Test methods for laser beam parameters: Beam widths, divergence angle and beam propagation factor". Moreover, in ISO11146-3 it also presents another alternative method - the variable apertures to measure beam divergence. According to ISO11146, we developed a novel automated laser measurement system with two methods for laser beam characterization, especially for synchronously determining beam divergence. It is also presented for the comparison of two methods measuring beam divergence, while their respective advantages and disadvantages are pointed out in this paper. It has been proved in practice that the auto measurement system based on two methods is an affective and convenient instrument for determining beam divergence.