Shaping the intensity and degree of coherence of a partially coherent beam by a 4f optical system with an amplitude filter
TL;DR: In this article, a Gaussian Schell-model (GSM) beam with an amplitude filter in the frequency plane is used to shape the intensity and degree of coherence of a GSM beam.
Abstract: It is known that a 4f optical system with an amplitude filter can be adopted to shape the intensity of a coherent Gaussian beam. In this paper, we investigate the propagation of a typical kind of partially coherent beam called a Gaussian Schell-model (GSM) beam through a 4f optical system with an amplitude filter in the frequency plane. It is demonstrated both numerically and experimentally that the 4f optical system with an amplitude filter can be used to shape the intensity and degree of coherence of a GSM beam simultaneously. The shaped beam displays interesting properties and forms controllable far-field intensity lattices, which may be useful for particle trapping and information transfer.
Citations
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TL;DR: A method to synthesize any partially coherent source (PCS) with a genuine cross-spectral density (CSD) function using complex transmittance screens using stochastic complex screen realizations is developed.
Abstract: We develop a method to synthesize any partially coherent source (PCS) with a genuine cross-spectral density (CSD) function using complex transmittance screens. Prior work concerning PCS synthesis with complex transmittance screens has focused on generating Schell-model (uniformly correlated) sources. Here, using the necessary and sufficient condition for a genuine CSD function, we derive an expression, in the form of a superposition integral, that produces stochastic complex screen realizations. The sample autocorrelation of the screens is equal to the complex correlation function of the desired PCS. We validate our work by generating, in simulation, three PCSs from the literature-none has ever been synthesized using stochastic screens before. Examining planar slices through the four-dimensional CSD functions, we find the simulated results to be in excellent agreement with theory, implying successful realization of all three PCSs. The technique presented herein adds to the existing literature concerning the generation of PCSs and can be physically implemented using a simple optical setup consisting of a laser, spatial light modulator, and spatial filter.
27 citations
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TL;DR: In this paper, a numerical approach is proposed to simulate the degree of coherence (DOC) of a partially coherent beam (PCB) with a Schell-model correlator in any transverse plane during propagation.
Abstract: In this paper, we propose a numerical approach to simulate the degree of coherence (DOC) of a partially coherent beam (PCB) with a Schell-model correlator in any transverse plane during propagation. The approach is applicable for PCBs whose initial intensity distribution and DOC distribution are non-Gaussian functions, even for beams for which it is impossible to obtain an analytical expression for the cross-spectral density (CSD) function. Based on our approach, numerical examples for the distribution of the DOC of two types of PCBs are presented. One type is the partially coherent Hermite–Gaussian beam. The simulation results of the DOC agree well with those calculated from the analytical formula. The other type of PCB is the one for which it is impossible to obtain an analytical expression of CSD. The evolution of the DOC with the propagation distance and in the far field is studied in detail. Our numerical approach may find potential applications in optical encryption and information transfer.
15 citations
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TL;DR: In this article, the spectral degree of coherence via spatial filtering is controlled by applying Fourier and statistical optics theory, which is verified with Monte Carlo wave-optics simulations of spatial coherence control and beam shaping for free-space optical communications and directed energy applications.
Abstract: This paper presents the theory for controlling the spectral degree of coherence via spatial filtering Starting with a quasi-homogeneous partially coherent source, the cross-spectral density function of the field at the output of the spatial filter is found by applying Fourier and statistical optics theory The key relation obtained from this analysis is a closed-form expression for the filter function in terms of the desired output spectral degree of coherence This theory is verified with Monte Carlo wave-optics simulations of spatial coherence control and beam shaping for potential use in free-space optical communications and directed energy applications The simulated results are found to be in good agreement with the developed theory The technique presented in this paper will be useful in applications where coherence control is advantageous, eg, directed energy, free-space optical communications, remote sensing, medicine, and manufacturing
9 citations
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TL;DR: NPCTABs are more stable during their propagation in free space and can maintain their Airy-like profile for an extended propagation distance, and the interesting and tunable characteristics of these novel beams may find applications in particle trapping, phase retrieval, and optical imaging.
Abstract: We propose theoretically and numerically, for the first time, the generation of novel partially coherent truncated Airy beams (NPCTABs) with Airy-like distributions for both intensity and degree of coherence via Fourier phase processing. We demonstrate a clear link between the magnitude and frequency of intensity and degree of coherence distributions oscillations of generated beams, and the source coherence and the phase screen parameter. Thus, the source coherence and phase can serve as convenient parameters to control the intensity and degree of the coherence of NPCTABs. Furthermore, we discover that NPCTABs are more stable than the fully coherent truncated Airy beams (FCTABs) during their propagation in free space and can maintain their Airy-like profile for an extended propagation distance. The interesting and tunable characteristics of these novel beams may find applications in particle trapping, phase retrieval, and optical imaging.
8 citations
References
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01 Jan 1995
TL;DR: In this article, the authors present a systematic account of optical coherence theory within the framework of classical optics, as applied to such topics as radiation from sources of different states of coherence, foundations of radiometry, effects of source coherence on the spectra of radiated fields, and scattering of partially coherent light by random media.
Abstract: This book presents a systematic account of optical coherence theory within the framework of classical optics, as applied to such topics as radiation from sources of different states of coherence, foundations of radiometry, effects of source coherence on the spectra of radiated fields, coherence theory of laser modes, and scattering of partially coherent light by random media. The book starts with a full mathematical introduction to the subject area and each chapter concludes with a set of exercises. The authors are renowned scientists and have made substantial contributions to many of the topics treated in the book. Much of the book is based on courses given by them at universities, scientific meetings and laboratories throughout the world. This book will undoubtedly become an indispensable aid to scientists and engineers concerned with modern optics, as well as to teachers and graduate students of physics and engineering.
7,658 citations
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TL;DR: In this article, a quasi-monochromatic Gaussian laser beam propagating in atmospheric turbulence is examined by using a derived analytic expression for the cross-spectral density function.
Abstract: A partially coherent quasi-monochromatic Gaussian laser beam propagating in atmospheric turbulence is examined by using a derived analytic expression for the cross-spectral density function. Expressions for average intensity, beam size, phase front radius of curvature, and wave-front coherence length are obtained from the cross-spectral density function. These results provide a model for a free-space laser transmitter with a phase diffuser used to reduce pointing errors.
510 citations
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01 Oct 2007
TL;DR: In this article, elementary coherence phenomena in the space-time domain and higher-order coherence effects in scattering have been studied, and the Unified theory of polarization and coherence Appendices Index has been proposed.
Abstract: Preface 1. Elementary coherence phenomena 2. Mathematical preliminaries 3. Second-order coherence phenomena in the space-time domain 4. Second-order coherence phenomenon in the space-frequency domain 5. Radiation from sources of different states of coherence 6. Coherence effects in scattering 7. Higher-order coherence effects 8. Elementary theory of polarization of stochastic electromagnetic beams 9. Unified theory of polarization and coherence Appendices Index.
420 citations
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TL;DR: A sufficient condition for ensuring the satisfaction of the constraint of nonnegative definiteness on the choice of the mathematical form of spatial correlation functions for optical fields is discussed.
Abstract: The choice of the mathematical form of spatial correlation functions for optical fields is restricted by the constraint of nonnegative definiteness. We discuss a sufficient condition for ensuring the satisfaction of such a constraint.
364 citations
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TL;DR: The quality and visibility of the ghost image are influenced by the source's transverse size, coherence width, and object characteristics, and the equation depends on both paths.
Abstract: We theoretically study ghost imaging with incoherent and partially coherent light radiation by using classical optical coherence theory. A Gaussian thin lens equation is derived for the ghost image. The equation depends on both paths. The quality and visibility of the ghost image are influenced by the source's transverse size, coherence width, and object characteristics. The differences between ghost imaging formed with incoherent light radiation and with entangled photon pairs are discussed.
250 citations