Imaging by Correlation of Intensity Fluctuations

Beard, Terry D.

doi:10.1063/1.1652979

Cited by 17 publications

(6 citation statements)

References 3 publications

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“…This approach has been applied in the temporal domain for reconstruction of just the amplitude of an object. 17 In this work, we recover the complex coherence function of the laser speckle arising out of an object hidden behind a random phase screen and employ this for the recovery of the hidden object, both amplitude and phase. The present work is different from that of Ref.…”

Section: Recovery Of Complex Valued Objects From Two-point Intensity mentioning

confidence: 99%

Recovery of complex valued objects from two-point intensity correlation measurement

Singh

Vinu

Sharma

2014

Applied Physics Letters

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We propose and experimentally demonstrate a technique for the recovery of the wavefront from spatially fluctuating fields using the two point intensity correlation, i.e., fourth order correlation. Assuming spatial ergodicity and Gaussian statistics for the speckle field, we connect the fourth order correlation to the modulus of the corresponding second order correlation. The idea is to retrieve the complex coherence function and consequently the wavefront using the off-axis holography. Application of this technique is demonstrated in the reconstruction of complex field of the object lying behind a weak scatterer. Experimental results of recovery of the complex field of phase objects “vortices” with three values of topological charges are presented.

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Section: Recovery Of Complex Valued Objects From Two-point Intensity mentioning

confidence: 99%

Recovery of complex valued objects from two-point intensity correlation measurement

Singh

Vinu

Sharma

2014

Applied Physics Letters

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“…Although this does not impede the measurement of centro-symmetric objects (indeed as was done with the Narrabri Stellar Intensity Interferometer), it has been shown that the phase can be recovered using correlations between more than two signals [12,13]. Also superimposing a coherent beam from a known reference source on the light beam of the target source would allow the recovery of the phase [12], see also [14,15].…”

Section: Basic Differences Between Michelson and Intensity Interferommentioning

confidence: 99%

Towards μ-arcsecond spatial resolution with Air Cherenkov Telescope arrays as optical intensity interferometers

Wit

LeBohec

Hinton

et al. 2008

J. Phys.: Conf. Ser.

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Abstract. In this poster contribution we highlight the equivalence between an Imaging Air Cherenkov Telescope (IACT) array and an Intensity Interferometer for a range of technical requirements. We touch on the differences between a Michelson and an Intensity Interferometer and give a brief overview of the current IACT arrays, their upgrades and next generation concepts (CTA, AGIS, completion 2015). The later are foreseen to include 30-90 telescopes that will provide 400-4000 different baselines that range in length between 50 m and a kilometre. Intensity interferometry with such arrays of telescopes attains 50µ-arc seconds resolution for a limiting mv ∼ 8.5. This technique opens the possibility of a wide range of studies, amongst others, probing the stellar surface activity and the dynamic AU scale circumstellar environment of stars in various crucial evolutionary stages. Here we discuss possibilities for using IACT arrays as optical Intensity Interferometers.

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“…These relationships are referred to as Wiener-Khintchine and Van Cittert-Zernike theorems'- 4 and provide, respectively, the bases for Fouier spectroscopy 5 , 6 and interferometric imaging. [7][8][9][10][11][12][13][14] Unfortunately, however, general radiative objects cannot uniquely be identified by these separate densities. For unique identification, the general power density G(x, y, v) that is dependent on both spatial position (x, y) and optical frequency v is desired.…”

Section: Introductionmentioning

confidence: 99%

“…This is because most of the incident flux is rejected by the spectral filter or the spectrometer slit. The multiplexing technique' 8 employed in Hadamard-transform spectrometers may improve the efficiency. The Hadamard-transform imaging spectrometers' 8 ' 19 literally aim to measure G(x, y, v), yet they have an additional purpose of using a single detector with the doubly multiplexing technique.…”

Section: Introductionmentioning

confidence: 99%

Fourier-transform spectral imaging: retrieval of source information from three-dimensional spatial coherence

Itoh

Ohtsuka

1986

J. Opt. Soc. Am. A

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A method is described for efficiently obtaining the comprehensive information of a polychromatic radiator. Under certain conditions both the spatial and spectral details of the radiative object can be recovered simultaneously from the three-dimensional spatial coherence function in the diffraction region. The recovery of object information is based on a Fourier-transform relationship derived from the basic formula [E. Wolf and W. H. Carter, J. Opt. Soc. Am. 68, 953-964 (1978)] describing the field correlation function in terms of the source correlation function. A new type of interferometer is proposed for the efficient collection of the spatial coherence data. Experimental results of the spectral-image recovery are also presented.

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Imaging by Correlation of Intensity Fluctuations

Cited by 17 publications

References 3 publications

Recovery of complex valued objects from two-point intensity correlation measurement

Recovery of complex valued objects from two-point intensity correlation measurement

Towards μ-arcsecond spatial resolution with Air Cherenkov Telescope arrays as optical intensity interferometers

Fourier-transform spectral imaging: retrieval of source information from three-dimensional spatial coherence

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