Time-resolved imaging of millimeter waves using visible continuum from the positive column of a Cs–Xe dc discharge

Gitlin, M. S.; Golovanov, V.; Spivakov, A. G.; Цветков, А. И.; Zelenogorskiy, V. V.

doi:10.1063/1.3327218

Cited by 17 publications

(29 citation statements)

References 46 publications

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“…Microwave-induced plasmas have been investigated extensively for applications including communications technology, plasma propulsion, and imaging. [5][6][7] Recent studies 8,9 of air breakdown by focused microwaves at 110 GHz near atmospheric pressure have observed the formation of large arrays of plasma filaments (∼ 50-100 filaments) oriented along the electric field vector E. The array resembles a triangular lattice in the plane defined by the incident beam direction k and the magnetic field vector H (H plane), with filaments separated by approximately one quarter of the microwave wavelength λ. The pattern progresses antiparallel to k in discrete steps due to reflection of the incident radiation by the plasma filaments, which creates a standing-wave pattern that causes subsequent breakdowns at the nearest intensity peaks λ/4 upstream.…”

mentioning

confidence: 99%

Pressure dependence of plasma structure in microwave gas breakdown at 110 GHz

Cook

Shapiro

Temkin

2010

Applied Physics Letters

134

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Recent studies of 110 GHz microwave discharges in air at atmospheric pressure have demonstrated formation of a large array of quarter-wavelength-spaced plasma filaments. Here we present measurements showing that as pressure is decreased from atmosphere to a few torr, the discharge transitions from a well-defined array to a smeared-out array and finally to a diffuse plasma. Despite the distinct nature of breakdown phenomena at high microwave frequencies, the pressure dependence of the breakdown threshold field is seen to follow a Paschen-type curve. Data for air and argon at 110 GHz are compared with previous low-frequency data.

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mentioning

confidence: 99%

Pressure dependence of plasma structure in microwave gas breakdown at 110 GHz

Cook

Shapiro

Temkin

2010

Applied Physics Letters

134

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“…This is 6 orders of magnitude better than in Ref. [18]. Figure 4 shows the response time that was measured in our system directly from the photodetector output.…”

Section: A Detection and Proof Of Conceptmentioning

confidence: 71%

“…Comparison of our system to another imaging system using an upconversion method described before in Ref. [18] shows that the sensitivity of our imaging technique exceeds the other technique's sensitivity by about 6 orders of magnitude (by comparing the minimum detectable signal power densities of both systems). Also, our system response time is about 2 times better than that of the other technique.…”

Section: Discussionmentioning

confidence: 83%

“…The minimum detectable MMW power density of this system was found to be on the order of 1 W∕cm 2 for 35 GHz radiation, the response time of this technique was about 0.8 μs, and the spatial resolution for a time slot of 10 μm was 3 mm. For longer time slots the resolution is worse due to heat transfer of the plasma [18]. Our system is several orders of magnitude more sensitive than those two techniques that use high-power sources, as discussed later, and exhibits a better response time.…”

Section: Introductionmentioning

confidence: 98%

“…Another MMW imaging technique based on visible light emitted from the positive column of a Cs-Xe DC discharge was shown in Ref. [18]. In that technique, MMW radiation is incident toward a large, uniform positive column window and causes changes in the positive column light intensity.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Detection and upconversion of three-dimensional MMW/THz images to the visible

Aharon¹,

Rozban²,

Klein³

et al. 2016

Photon. Res.

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We present an inexpensive technique to obtain a three-dimensional (3D) millimeter wave (MMW) and terahertz (THz) image using upconversion. In this work we describe and demonstrate a method for upconversion of MMW/ THz radiation to the visual band using a very inexpensive miniature glow discharge detector (GDD) and a silicon photodetector. We present MMW/THz upconversion images based on measuring the visual light emitting from the GDD rather than its electrical current. The results show better response time and better sensitivity compared to the electronic detection performed previously. Furthermore, in this work we perform frequency modulation continuous wave (FMCW) radar detection based on this method using a GDD lamp, with a photodetector to measure GDD light emission. By using FMCW detection, the range in addition to the intensity at each pixel can be obtained, thus yielding the 3D image. The GDD acts as a heterodyne mixer not only electronically but also optically. The suggested 3D upconversion technique using the GDD is simple and inexpensive and has better performance compared to other MMW/THz imaging systems suggested in the literature. This method provides minimum detectable signal power that is about 6 orders of magnitude better than similar plasma systems due to the very large internal signal gain deriving from the much smaller electrode separation and resulting in much higher plasma electric field.

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Nonlocality of microwave-induced variations in the intensity of the visible continuum from a medium-pressure cesium-xenon dc discharge

et al. 2012

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A violation of the local relation between the visible continuum (VC) emissivity and the millimeter wave (MMW) intensity was observed in the experiments on imaging of MMW beams with subcentimeter width using the VC from a slab of the positive column (PC) of a medium-pressure cesium-xenon (Cs-Xe) dc discharge. The spatial distribution of the microwave-induced variation in the VC emissivity of the plasma slab was modeled. For this, perturbations of the electron temperature and density in a slab of the PC of a Cs-Xe discharge affected by an MMW beam were calculated. The relation between the spatial distributions of the VC brightness perturbation and the MMW intensity has been obtained. Good agreement between the results of the experiments and the modeling is demonstrated. The line spread function of a two-dimensional (2D) plasma sensor for MMWs is found, and its width is shown to be equal to 2 mm. We proved that the nonlocality of microwave-induced variations in the intensity of the VC from the PC, as well as the spatial resolution of the plasma technique of MMW imaging, are primarily determined by the influence of the electron heat conduction. Along with the electron heat conduction, the nonlocality of the electron temperature variation is caused by the influence of the hydrodynamic flux of electron enthalpy, diffusion and thermodiffusion fluxes of electrons, and also spatial inhomogeneity of the electron heating by a dc electric field, which results from a microwave-induced variation in plasma conductivity. These factors are responsible for the axial asymmetry of the images of the axisymmetric MMW beams.

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Time-resolved imaging of millimeter waves using visible continuum from the positive column of a Cs–Xe dc discharge

Cited by 17 publications

References 46 publications

Pressure dependence of plasma structure in microwave gas breakdown at 110 GHz

Pressure dependence of plasma structure in microwave gas breakdown at 110 GHz

Detection and upconversion of three-dimensional MMW/THz images to the visible

Nonlocality of microwave-induced variations in the intensity of the visible continuum from a medium-pressure cesium-xenon dc discharge

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