A more accurate method of evaluating the standard deviation of speckle phase

A phase angle is constructed to estimate the standard deviation of speckle phase. The relative accurate amending expression of the standard deviation of speckle phase is derived according to the statistical properties of speckle phase of the fully developed speckle fields. The theoretical values of standard deviation are compared with that which are calculated from the Gaussian theory of the speckle field. The theoretical results are compared and discussed with respect to the experimental results of Kadono et al.