Large Aperture Diffraction Limited Optical Synthetic Aperture System Intermediate Frequency MTF Compensation

Tomography of complex three-dimensional objects with ultrasound or microwave has been a long-standing goal since the introduction of these technologies after World War II. While current state-of-the-art systems can provide high-resolution images of cylindrical objects characterized by a two-dimensional structure, the three-dimensional case remains an open challenge owing to current limitations of sensor technology and computer power. Here, this problem is addressed by means of a synthetic aperture technique that, while using hardware technology developed for two-dimensional problems, accounts for the complexity of three-dimensional scattering and leads to high-resolution three-dimensional reconstructions. In this paper, we present the theoretical formulation of this new approach and illustrate it by means of a numerical example.

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A Computational Study of Reconstruction Algorithms for Synthetic Aperture Diffraction Tomography: Interpolation Versus Interpolation-Free

Acoustical Imaging ◽

10.1007/978-1-4613-0725-9_40 ◽

1988 ◽

pp. 421-443 ◽

Cited By ~ 3

Author(s):

Jian-Yu Lu

Keyword(s):

Computational Study ◽

Synthetic Aperture ◽

Diffraction Tomography ◽

Reconstruction Algorithms ◽

Aperture Diffraction

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Large-aperture synthetic aperture imaging ladar

Optical Engineering ◽

10.1117/1.oe.57.12.123102 ◽

2018 ◽

Vol 57 (12) ◽

pp. 1

Author(s):

Yanan Zhi ◽

Yu Zhou ◽

Jianfeng Sun ◽

Enwen Dai ◽

Weiqing Pan ◽

...

Keyword(s):

Synthetic Aperture ◽

Synthetic Aperture Imaging ◽

Large Aperture

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A Novel Range Compression Algorithm for The~Resolution Enhancement in GNSS-SAR

10.20944/preprints201703.0179.v1 ◽

2017 ◽

Author(s):

Yu Zheng ◽

Yang Yang ◽

Wu Chen

Keyword(s):

Imaging System ◽

Resolution Enhancement ◽

Intermediate Frequency ◽

Satellite System ◽

Compression Algorithm ◽

Synthetic Aperture ◽

Range Resolution ◽

Resolution Improvement ◽

Simulation Results ◽

Global Navigation Satellite

Passive Global Navigation Satellite System (GNSS)-based Synthetic Aperture Radar (SAR), known as GNSS-SAR, is a new passive radar imaging system. However, compared with conventional SAR, range resolution of GNSS-SAR is significantly lower. To improve range resolution of GNSS-SAR is an interested topic for investigation. In this paper, a novel range compression algorithm for enhancing range resolutions of GNSS-SAR is proposed. In the proposed scheme, at first, range compression is conducted by correlating the received reflected GNSS signal of intermediate frequency (IF) with the synchronized direct baseband GNSS signal in range domain. Then spectrum equalization is applied to the compressed results to suppress side lobes. Both theoretical analysis and simulation results have demonstrated that significant range resolution improvement in GNSS-SAR can be obtained by the proposed range compression algorithm, compared to the conventional range compression algorithm.

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Analysis of wavefront effects for large-aperture tiled-grating compressor

Laser and Particle Beams ◽

10.1017/s0263034617000878 ◽

2018 ◽

Vol 36 (1) ◽

pp. 84-91

Author(s):

S. Zhang ◽

J. W. Zhang ◽

Y. Zhou ◽

J. Q. Su ◽

X. Wang ◽

...

Keyword(s):

Focal Spot ◽

Input Pulse ◽

Output Pulse ◽

Large Aperture ◽

Spot Quality ◽

Wavefront Error ◽

Aperture Diffraction ◽

Coating Stress ◽

Wave Aberration ◽

Intensity Laser

AbstractMonolithic large-aperture diffraction grating tiling is desired to increase the output capability of multi-kilojoule petawatt laser facilities. However, the wavefront errors of input pulse and gratings will degrade the focal spot quality and the compressibility of the output pulse. In this work, the effects of wavefront error of input pulse, deformation and wave aberration of the grating for the large-aperture tiled-grating compressor are investigated theoretically. A series of numerical simulations are presented to discuss the changing trends of focal spot energy caused by wavefront error of input pulse and obtain the error tolerance for specific goals. The influences of coating stress and the wave aberration of holographic exposure gratings on the diffraction wavefront are also discussed. Some advice is proposed for improving the performance of large-aperture tiled-grating. This work paves the way for the design of practical large-aperture tiled-grating compressor for ultrahigh intensity laser facilities in the future.

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