Two-dimensional all-optical spatial light modulation with high speed in coherent media.
ABSTRACT We show theoretical evidence that coherent systems based on electromagnetically induced transparency (EIT) can function as optically addressed spatial light modulators with megahertz modulation rates. The transverse spatial properties of cw probe fields can be modulated fast using two-dimensional optical patterns. To exemplify our proposal, we study real-time generation and manipulation of Laguerre-Gaussian beams by means of phase or amplitude modulation using flat-top image-bearing pulse trains as coupling fields in low-cost hot vapor EIT systems.
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ABSTRACT: We theoretically explore an all-optical method for generating tunable diffractive Fresnel lenses in coherent media based on electromagnetically induced transparency. In this method, intensity-modulated images in coupling light fields can pattern the coherent media to induce the desired modulo-2π quadratic phase profiles for the lenses to diffract probe light fields. We characterize the focusing and imaging properties of the induced lenses. In particular, we show that the images in coupling fields can flexibly control the images in probe fields by diffraction, where large focal length tunability from 1 m to infinity and high output (∼ 88% diffraction efficiency) can be achieved. Additionally, we also find that the induced Fresnel lenses can be rapidly modulated with megahertz refresh rates using image-bearing square pulse trains in coupling fields. Our proposed lenses may find a wide range of applications for multimode all-optical signal processing in both the classical and quantum regimes.Optics Express 01/2011; 19(2):981-93. · 3.55 Impact Factor
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ABSTRACT: We demonstrate the use of cylindrical vector beams - beams with spatially varying polarization - for detecting and preparing the spin of a warm rubidium vapor in a spatially dependent manner. We show that a modified probe vector beam can serve as an atomic spin analyzer for an optically pumped medium, which spatially modulates absorption of the beam. We also demonstrate space-variant atomic spin by optical pumping with the vector beams. The beams are thus beneficial for making single-shot polarization-dependent measurements, as well as for providing a means of preparing samples with position-dependent spin.Optics Express 12/2011; 19(25):25143-50. · 3.55 Impact Factor
Conference Paper: An optoelectronic expert system for knowledge base systems.[Show abstract] [Hide abstract]
ABSTRACT: In this paper a parallel optoelectronic computer architecture is proposed for expert systems in order to achieve high speed and high performance for parallel processing of rule-based systems. The proposed system is modeled and implemented using a two-dimensional space optics symbolic correlator to perform the comparison operations of the expert system. Also in this paper, an optoelectronic system for a parallel inference engine is presented. The proposed optical inference engine is able to perform 3D processing for inferring conclusions to queries by representing knowledge (facts and rules) in 2D space using a matrix-like formulation. The proposed structure of the inference machine is based on rule-driven and query-driven control flows using mapped-template logic. A hardware realization for these systems based on commercially available components is discussed. The performance analysis of the proposed system shows its remarkably improved performance compared with electronic systems.10th International Conference on Intelligent Systems Design and Applications, ISDA 2010, November 29 - December 1, 2010, Cairo, Egypt; 01/2010