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 intensity between the multiplied foci varies in general in one period, es- pecially if the light in the spacing between the lenses is not absorbed but transmitted. Additionally, in the case of microlenses with a high numeri- cal aperture the parabolic approximation or Fresnel diffraction, which is normally used to explain the Talbot effect, is no longer valid. A theoret- ical explanation and numerical simulations are given together with ex- perimental results. © 1997 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(97)02904-8)