Measurement of the adjustable slight roughness emulated by a spatial light modulator employing the vortex beam...

In this paper, we analyze the speckle patterns generated by the scattering of optical vortex on different roughness surfaces, compared with those produced by Gaussian light, where the roughness is emulated by a spatial light modulator and adjustable. The scheme and experiments demonstrate an improvement with the vortex beam, especially for slight roughness measurements. In addition, since the topological charge used to produce speckle patterns has a great influence on the speckle size and can be optimized to adjust it for different object measurements, we also investigate how the roughness depends on the topological charge.