Measurement of the beam parameters of a laser beam and its diffraction field, using a hologram

A simple method for measuring the beam parameters of a laser beam, using a hologram, is proposed, and the accuracy is examined. By measuring the beam width and radius of curvature of the wavefront of a He-Ne gas laser, including several higher order modes, the behavior of a laser beam is investigated experimentally. As another application of this method, the phase distribution of the diffracted field from an aperture and a slit illuminated by a laser beam is measured, and the effects of a beam upon the diffracted field are studied experimentally.