Precise location of laser beam center and its applications

We use a area CCD to acquire the data of the beam profile of a He-Ne laser.According to the data,we utilize the minimum square deviation to get the intensity profile curve,and define the peak point as the center of the laser beam.The accuracy of center location can be about 1μm.Then we employ the method to measure the prism angle and get the measurement precision up to 0.004°.