Binary gratings with random heights.

Universidad Complutense de Madrid, Optics Department, Applied Optics Complutense Group, Facultad de Ciencias Físicas, Ciudad Universitaria s.n., 28040 Madrid, Spain.
Applied Optics (Impact Factor: 1.69). 07/2009; 48(16):3062-9. DOI: 10.1364/AO.48.003062
Source: PubMed

ABSTRACT We analyze the far-field intensity distribution of binary phase gratings whose strips present certain randomness in their height. A statistical analysis based on the mutual coherence function is done in the plane just after the grating. Then, the mutual coherence function is propagated to the far field and the intensity distribution is obtained. Generally, the intensity of the diffraction orders decreases in comparison to that of the ideal perfect grating. Several important limit cases, such as low- and high-randomness perturbed gratings, are analyzed. In the high-randomness limit, the phase grating is equivalent to an amplitude grating plus a "halo." Although these structures are not purely periodic, they behave approximately as a diffraction grating.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: It has long been known that random height variations of a repeated nanoscale structure can give rise to smooth angular color variations instead of the well-known diffraction pattern experienced if no randomization is present. However, until now there have been few publications trying to explain this and similar phenomena taking outset in electromagnetic theory. This paper presents a method for analyzing far-field reflection from a surface constructed by translated instances of a given structure. Several examples of the effect of random translations are given.
    Applied Optics 04/2014; 53(11):2405-2415. · 1.69 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Enhanced control of diffraction through transparent substrates is achieved via disordered gratings in a silica sol-gel film. Tailoring the degree of disorder allows tuning of the diffractive behavior from discrete orders into broad distributions over large angular range. Gratings of optical quality are formed by silica sol-gel nanoimprint lithography and an optical setup for the measurement of continuous diffraction patterns is presented. Sound agreement is found between measurements and simulation, validating both the approach for redirection of light and the fabrication process. The disordered gratings are presented in the context of improved interior daylighting and may furthermore be suited to a wide variety of applications where controlled angular redirection of light is desired.
    Applied Optics 02/2013; 52(4):709-16. · 1.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper aims to propose a computational approach in fluorescence second-order correlation imaging. In this regard, we experimentally demonstrate computational ghost imaging both with a transmission mask as a conventional ghost imaging and fluorescent object as a reflective type. Within this framework, we employ size of object and resolution of speckle pattern as the variables in order to investigate important characteristics of ghost images such as: visibility, resolution, and contrast. Analysis of variables to obtain promoted color ghost images faster is our main objective.
    The European Physical Journal D 03/2013; 67(2). · 1.40 Impact Factor

Full-text (2 Sources)

Available from
Jun 6, 2014