Measurement of roughness based on the Talbot effect in reflection from rough surfaces.

摘要: In the present work, Talbot effect of a square grating is analyzed when light reflected from rough surface. It shown theoretically that scattered intensity in Fresnel diffraction limit depends on statistical properties surface, angle incidence light, period, and geometric coefficient, related to ratio distance surface observation plane grating. At distances grating, height difference function, terms multiplication number, coefficient modulation transfer function (MTF) scattering reflection If argument larger than twice correlation length, constant for different spatial frequencies. Therefore, wave reproduced with smaller contrast. The roughness can be obtained by measuring contrast at incident angles. also measurements both transmission, provide refractive index transparent samples experimental studies, three metal standard surfaces are determined angles incidence. Also, sheet glass obtained. results quite consistent.