Numerical investigation on the speckle formation produced by Fourier domain phase modulation
Speckle size is an important optical property since it is closely related to the resolution of laser-based techniques such holography, interferometry, and phase retrieval. Here the effects of introducing additional spherical phase to the incident beam on the speckle formed by phase modulation in the Fourier plane are investigated. Speckle formation for different spherical phase curvatures, depths of randomization, and propagation distances are analyzed. Results show that the speckle size generally decreases when curvature, depth of randomization, and propagation increases, with the curvature having a larger impact on speckle size. The results can be used in the optimization and control of speckle fields involving active optical systems.