Correlated interference modulated by mathematical algorithms established using a he-ne laser

We study the thermal light correlated interference using a He-Ne laser beam with intensities modulated by mathematical functions. Three mathematical functions are adopted: A power function f [I(x)] = I n(x); an exponential function f [I(x)] = exp[ pI(x)]; and an inverse trigonometric function f [I(x)] = tan-1[qI(x)]. Our results show that these correlation methods influence the contrast of correlated interference fringes, but not the periods of the fringes, which just depend on the relation of correlated spatial coordinates.