Wave optics simulation of atmospheric turbulence and reflective speckle effects in CO_2 lidar

Nelson, Douglas H.; Walters, Donald L.; MacKerrow, Edward P.; Schmitt, Mark J.; Quick, C. R.; Porch, W.M.; Petrin, Roger R.

doi:10.1364/ao.39.001857

Cited by 32 publications

(12 citation statements)

References 46 publications

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“…The speckle simulation was validated with theory for a Gaussian beam target and circular telescope aperture previously made by Nelson [8]. Our case is different than theirs, however, since their beam was fully encompassed by the target surface.…”

Section: Notice Inmentioning

confidence: 77%

Simulation and theory of speckle noise for an annular aperture frequency-modulation differential-absorption LIDAR (FM-DIAL) system

et al. 2009

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This paper presents theory of speckle noise for a frequency-modulation differential-absorption LIDAR system along with simulation results. These results show an unexpected relationship between the signal-to-noise ratio (SNR) of the speckle and the distance to the retro-reflector or target. In simulation, the use of an annular aperture in the system results in a higher SNR at midrange distances than at short or long distances. This peak in SNR occurs in the region where the laser's Gaussian beam profile approximately fills the target. This was unexpected since it does not occur in the theory or simulations of the same system with a circular aperture. By including the autocorrelation of this annular aperture and expanding the complex correlation factor used in speckle models to include conditions not generally covered, a more complete theoretical model is derived for this system. Obscuration of the center of the beam at near distances is also a major factor in this relationship between SNR and distance. We conclude by comparing the resulting SNR as a function of distance from this expanded theoretical model to the simulations of the system over a double-pass horizontal range of 10 meters to 10 km at a wavelength of 1.28 micrometers

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Section: Notice Inmentioning

confidence: 77%

Simulation and theory of speckle noise for an annular aperture frequency-modulation differential-absorption LIDAR (FM-DIAL) system

et al. 2009

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“…To simulate a reflection from a diffuse surface, we first apply a random phase uniformly distributed from zero to 2 to the electric field envelope at each grid point 11 . The random phases are pairwise uncorrelated.…”

Section: Diffuse Reflectormentioning

confidence: 99%

Enhanced backscatter of optical beams reflected in atmospheric turbulence

Nelson

Palastro

et al. 2014

SPIE Proceedings

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Optical beams propagating through the atmosphere acquire phase distortions from turbulent fluctuations in the refractive index. While these distortions are usually deleterious to propagation, beams reflected in a turbulent medium can undergo a local recovery of spatial coherence and intensity enhancement referred to as enhanced backscatter (EBS). Using simulations, we investigate the EBS of optical beams reflected from mirrors, corner cubes, and rough surfaces, and identify the regimes in which EBS is most distinctly observed. Standard EBS detection requires averaging the reflected intensity over many passes through uncorrelated turbulence. Here we present an algorithm called the "tilt-shift method" which allows detection of EBS in static turbulence, improving its suitability for potential applications.

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“…He based much of his analysis on work by Abarbanel et al (1994), which reviewed the issues involved with using LIDAR for remote sensing of chemical agents. MacKerrow and Schmitt (1997) ran extensive experiments on speckle statistics from CO 2 LIDAR returns, while Nelson et al (2000) used 4.2 simulation techniques to study both turbulence and speckle for CO 2 LIDAR. Both of these studies were associated with the DOE CALIOPE project.…”

Section: Impact Of Speckle On the Fm-dial Systemmentioning

confidence: 99%

Laser Remote Sensing: FY07 Summary Report

Harper¹,

Strasburg²,

Golovich³

et al. 2007

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SummaryStandoff detection and characterization of chemical plumes using Frequency Modulated Differential Absorption LIDAR (FM-DIAL) is a promising technique for the detection of nuclear proliferation activities. For the last several years Pacific Northwest National Laboratory (PNNL) has been developing an FM-DIAL-based remote sensing system as part of PNNL's Infrared Sensors project within NA-22's Enabling Technologies portfolio. In FY06 the remote sensing effort became a stand-alone project within the Plutonium Production portfolio with the primary goal of transitioning technology from the laboratory to the user community.Current systems remotely detect trace chemicals in the atmosphere over path lengths of hundreds of meters for monostatic operation (without a retro-reflector target) and up to ten kilometers for bistatic operation (with a retro-reflector target). The FM-DIAL sensor is sensitive and highly selective for chemicals with narrowband absorption features on the order of 1-2 cm -1 ; as a result, the FM-DIAL sensors are best suited to simple di-atomic or tri-atomic molecules and other molecules with unusually narrow absorption features. A broadband sensor is currently being developed. It is designed to detect chemicals with spectral features on the order of several 10s of wavenumbers wide. This will expand the applicability of this technology to the detection of more complicated molecules. Our efforts in FY07 focused on the detection of chemicals associated with the PUREX process.The highest value performance measure for FY07, namely the demonstration of the Broadband Laser Spectrometer (BLS) during chemical release experiments, was successfully achieved in June, July, and August of this year. Significant advancements have been made with each of the other tasks as well. A short-wave infrared version of the miniature FM-DIAL (FM-Mini) instrument was successfully demonstrated during field tests in June. During FY07 another version of the FM-Mini was built using long-wave infrared components. This instrument was deployed for field tests in July and August. The modeling task continued to study the impact of speckle on the FM-DIAL system as well as make further advancements in the sophistication of the numerical simulations.v

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Wave optics simulation of atmospheric turbulence and reflective speckle effects in CO_2 lidar

Cited by 32 publications

References 46 publications

Simulation and theory of speckle noise for an annular aperture frequency-modulation differential-absorption LIDAR (FM-DIAL) system

Simulation and theory of speckle noise for an annular aperture frequency-modulation differential-absorption LIDAR (FM-DIAL) system

Enhanced backscatter of optical beams reflected in atmospheric turbulence

Laser Remote Sensing: FY07 Summary Report

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