Real-time holograms generated by second-harmonic cross correlation of object and reference optical wave fields

Abstract

Three-dimensional holographic images of extended diffusing objects are simultaneously recorded and reconstructed by optical cross correlation in a second-order nonlinear crystal. An interaction geometry in which the phase-matched object and reference fields propagate slightly noncollinearly is particularly convenient for producing these second-harmonic-generated holograms.

Boolean algebra operations performed on optical bits by the generation of holographic fields through second-order nonlinear interactions

“…3͑a͒. 12,15 Moreover, such a resolution was qualitatively confirmed in the experiments we performed on a number of both 2D and 3D objects, 13,14 although the objects were necessarily illuminated through the diffuser S. 3͑b͔͒.…”

“…In previous works [12][13][14][15] in which the r-beam wave front was not modulated in amplitude we demonstrated that the wave front generated at 2 by SHCC reconstructs a holographic image of the object that had imprinted the amplitude ͑and phase͒ modulation onto the o-beam. This SHG holographic image is a virtual image ͑OЈ in Fig.…”

“…1, which is similar to the one we used for making SHG holograms of real one-, two-, and three-dimensional ͑3D͒ objects. Before illuminating the mask, the o-beam was passed through a diffuser ͑S͒ to randomize its wave front 13,14 and to scatter it over an angle of 50 mrad. Quanta-Ray GCR-4, Spectra-Physics Inc., Mountain View, CA͒ was split into two beams, one 10% of the other in energy.…”

The Holographic Principle and Emergence Phenomenon

“…This idea has been realized by D. Gabor, the inventor of holographic technique [Gabor, 1946] who proved that complete "structural" information about a scene/object under observation may be obtained through recording the phase-differences of interacting waves. It is known, that a periodic grating built in a nonlinear medium may generate real-time diffraction patterns [Denisyuk et al, 2000]. A rapidly developing field of the real-time holography deals with nonlinear holographic gratings, where the read-write processes proceed simultaneously.…”

Second-harmonic generated holograms

“…We proved our theory by studying the impulse-response of SHG holograms in experiments in which a point-like source was used as the object, as well as by reconstructing SHG holographic images of one-dimensional [ 1,2] and two-and three-dimensional objects [5,6]. Here we describe experiments on the generation of 3-D holographic images of arbitrary diffusing objects and demonstrate that SHG holograms are endowed with all the characteristics of conventional holograms.…”