FRACTIONAL TALBOT EFFECT FOR PERIODIC MICROLENS ARRAYS

It is well known that the foci of a periodic array of microlenses are reproduced and multiplied in the fractional Talbot planes. But the int ensity between the multiplied foci varies in general in one period, es pecially if the light in the spacing between the lenses is not absorbe d but transmitted. Additionally, in the case of microlenses with a hig h numerical aperture the parabolic approximation or Fresnel diffractio n, which is normally used to explain the Talbot effect, is no longer v alid. A theoretical explanation and numerical simulations are given to gether with experimental results. (C) 1997 Society of Photo-Optical in strumentation Engineers.