A simple geometrical model was developed for calculation of the contrast of a polychromatic image-plane speckle pattern from a source of light with high spatial coherence. It is based on counting the number of independent speckle patterns that contribute to a given point in the image plane. This results in a simple equation for the contrast as a function of imaging geometry; relative orientation of the projection direction, observation direction, and specimen normal; bandwidth of the light source; and surface roughness. Its validity was established by comparison with an exact solution: rms errors in the calculated contrast were only 0.033 over a wide range of parameter values likely to be encountered in practice.
© 1999 Optical Society of America
Original Manuscript: May 21, 1998
Published: April 10, 1999
Jonathan M. Huntley, "Simple model for image-plane polychromatic speckle contrast," Appl. Opt. 38, 2212-2215 (1999)