Ronald L. Fante’s research while affiliated with United States Air Force and other places

... Many imaging systems, including terrestrial and satellite imaging, underwater imaging, and microscopy through biological tissues, are significantly impacted by the non-homogeneous nature of the propagation medium. The primary factors influencing light propagation in such media include absorption, scattering, and fluctuations in the refractive index due to optical turbulence [3]. These turbulenceinduced fluctuations lead to wavefront distortions, causing phenomena such as beam spreading, beam wander, and a loss of spatial coherence of the electromagnetic field. ...

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Robustness of chaotic-light correlation plenoptic imaging against turbulence

... The statistical theory of turbulence gave an understanding of how one can describe complex random systems, while the theory of random functions provided the rigorous mathematical apparatus for dealing with signals modulated randomly in phase and amplitude. Among such landmarks are the introduction of the concept of locally homogeneous random media (Obukhov, 1949), the development of Rytov's theory of smooth perturbations (Obukhov, 1953), the derivation of field moment equations (Shishov, 1968), the asymptotic methods for solving such equations (Fante, 1975b;Gochelashvily & Shishov, 1975;Yakushkin, 1975) and computable modeling of ionospheric scintillation (Rino, 1979a(Rino, , 1979bVasylyev et al., 2022;Hamza et al., 2024). These concepts allow one to establish a rigorous mathematical framework for dealing with wave propagation in the ionosphere, and to derive further universally applicable formulas for scintillation indices. ...

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Global Ionospheric Scintillation Estimation Based on Phase Screen Modeling From One‐Dimensional Satellite Data

... From the theoretical point of view, analysis of wave propagation can be carried out in a perturbative regime using in particular Rytov theory with small fluctuations in the wave field to obtain insight about the scintillation [14,15]. The fluctuations of intensity and how they depend on source coherence time have been studied in [16,17] in the situation when the detector response time is either short or long compared to the source coherence time, but in general, short compared to the time scale at which the medium changes. We shall refer to the case when the detector averaging time is short, respectively, long, compared to the source coherence time as a fast, respectively, slow, detector. ...

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Scintillation of partially coherent light in time-varying complex media

... If a monochromatic wave propagates in the z direction, the wave field e(x, y, z) can be written as e(x, y, z) = u(x, y, z) e -i(~' '-kz) We shall consider the cases when following two assumptions are valid. First when 82u/Sz2 is small, the wave equation can be written approximately as [1,2] ...

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Wave propagation in a random medium: The solution of the m-n th moment equation with different wavenumbers

... (2.42) in evaluating the correlation function for normalized intensity in strong turbulence have been given by Fante [23,24], although beware of a critical error in the power of t in the g(W) function in Equation (6) of reference [24], where it is written as t 8/3 but should be t 8/11 as defined correctly by Fante in reference [23]. These functions are ...

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Studies of the effects of atmospheric turbulence on free space optical communications

... The exploration of time interfaces has led to exciting new physical phenomena [22][23][24][25][26] , including temporal aiming 27 , temporal multilayer structures modelling higher-order transfer functions 28 and impedance transformers that can be used as temporal filters 29 , classical and quantum antireflection temporal coating 30,31 , temporal analogue of metasurface unit cells 32 , broadband light sculpting 33 , analogue of Faraday polarization rotation at time interface in magnetoplasma 34 , broadband frequency translation 35 , the phase-conjugation of time-reflected waves 36 , temporal prism 37 and inverse prism 38,39 , temporal Brewster angle 40 , temporal twistronics 41 , amplification and holding of surface waves [42][43][44] , ultra slow surface waves 44 , propagating to evanescent waves coupling 45 , among others 18,[46][47][48][49][50][51][52][53] . Interestingly, the first experimental demonstrations of time interfaces have been reported in the past few years. ...

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Emulating time interfaces via smooth temporal transitions

... They found that MTF is related to second-order statistics of the field. In contrast to most of research, Fante has studied the imaging of incoherent sources through turbulence, and the results show that high spatial frequencies are not significantly affected by the turbulence; however, the lower frequencies may be affected considerably [6]. Yang et al. have given imaging expression of point object and plane mirror in turbulent medium [7]. ...

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IMAGE INTENSITY OF A GAUSSIAN ROUGH-SURFACE IN ATMOSPHERIC TURBULENCE

... since scintillated correlation widths are on the order of the first Fresnel zone radius √ λZ 1 and N F counts the number of Fresnel zones contained within the entrance pupil. Scintillation index reduces further through the use of polychromatic light, which Fante [17] and Baykal [18] have both shown to produce a bandwidth-averaging factor that applies to either spherical-or plane-wave illumination. Korotkova [19] more recently demonstrated how scintillation scales with polarization in the same way as speckle [cf. ...

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System-level noise performance of coherent imaging systems

... The physical interpretation of a phase screen statistics is dependent on how the scattering problem influences the optical phase power spectral density (PSD). 29 We propose a random phase screen framework, which includes scattering from particles that are smaller or comparable to the wavelength extendable to other propagation problems such as rough surfaces or biological tissue. This claim is only valid within the small-angle scattering approximation where large scattering angles are ignored; thus, the modeled scattering effects hold when |n p /n 0 − 1| ≪ 1 and 2ka|n p /n 0 − 1| ≪ 1, where n 0 is medium refractive index, and n p is the particle's refractive index, k = 2π/λ is the free-space wavenumber, and a is the particle radius. ...

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Phase Screen Modeling of Vortex Beam Propagation through a Turbid Medium

... (46) because it completely neglects the scattering within the medium. This is why the roots of Eq. (48) are not shown in Fig. 2. In contrast, the prediction of the resonance equation (46) of the effectivemedium theory is more reliable because it includes the effects of finite values of κ. ...

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Effective-medium approach to the resonance distribution of wave scattering in a random point field