Tomography of Optical Emission Line Intensities of a Radio-Frequency Magnetron Discharge

1997 ◽  
Vol 51 (9) ◽  
pp. 1340-1345 ◽  
Author(s):  
F. Debal ◽  
M. Wautelet ◽  
J. P. Dauchot ◽  
M. Hecq
Keyword(s):  
Radio Frequency ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Optical Tomography ◽  
Three Dimensional ◽  
Optical Emission ◽  
Ccd Camera ◽  
Experimental Setup ◽  
Mathematical Function ◽  
Magnetron Discharge

An experimental setup for spectroscopic optical tomography of glow discharges is presented. It combines a fiber-optics system with a monochromator coupled to a charge-coupled device (CCD) camera. The light emitted by the discharge is sent to the input of 10 optical fibers through a collimating system. The outputs of these optical fibers are coupled to the entrance slit of a monochromator. The CCD camera is in the output slit. This arrangement allowed us to acquire 10 spectra simultaneously, each being associated with a small zone of the discharge. By translation of the optical fibers, the whole discharge was studied. The data were then analyzed by means of a tomographic reconstruction program in order to obtain the three-dimensional spectroscopic optical tomography, for a large number of lines. This experimental setup was used to deduce the three-dimensional optical emission of various lines of a radio-frequency (rf)-powered magnetron discharge. The discharge deals with an aluminum base alloy cathode, sputtered by Ar. Emission lines corresponding to the cathode (Al: 394.4- and 396.2-nm lines) and the gas discharge (Ar: 763.5 nm-line) were considered. The three-dimensional emission profiles, I( r, Z), of the lines were measured; r is the distance from the center of the cathode, and Z is the distance from the cathode. I( r, Z) profiles are different for the Al and Ar lines. The effects of the electrical power and the pressure were also studied. It was found that the corresponding I( r, Z) profiles behave differently with the pressure. In order to compare the results, I( r, Z) was fitted with an empirical analytical mathematical function, with parameters depending on pressure. At high pressure, the shape of I( r, Z) for the Al line tends towards the shape of the Ar line.

Three-dimensional tomographically reconstructed optical emission profiles of Hall thruster plasmas

2021 ◽  
Author(s):  
jinwoo kim ◽  
Dongho Lee ◽  
Guentae Doh ◽  
Sanghoo Park ◽  
Holak Kim ◽  
...  
Keyword(s):  
Radiative Decay ◽  
Tomographic Reconstruction ◽  
Gaussian White Noise ◽  
Three Dimensional ◽  
Diagnostic System ◽  
Optical Emission ◽  
Ccd Camera ◽  
Hall Thruster ◽  
Plume Region ◽  
Reconstruction Performance

Abstract A diagnostic system was developed for spectrally resolved, three-dimensional tomographic reconstruction of Hall thruster plasmas, and local intensity profiles of Xe I and Xe II emissions were reconstructed. In this diagnostic system, 28 virtual cameras were generated using a single, fixed charge-coupled device (CCD) camera by rotating the Hall thruster to form a sufficient number of lines of sight. The Phillips-Tikhonov regularization algorithm was used to reconstruct local emission profiles from the line-integrated emission signals. The reconstruction performance was evaluated using both azimuthally symmetric and asymmetric synthetic phantom images including 5% Gaussian white noise, which resulted in a root-mean-square error of the reconstruction within an order of 10-3 even for a 1% difference in the azimuthal intensity distribution. Using the developed system, three-dimensional local profiles of Xe II emission (541.9 nm) from radiative decay of the excited state 5p4(3P2)6p2[3]˚5/2 and Xe I emission (881.9 nm) from 5p5(2P˚3/2)6p2[5/2]3 were obtained, and two different shapes were found depending on the wavelength and the distance from the thruster exit plane. In particular, a stretched central jet structure was distinctively observed in the Xe II emission profile beyond 10 mm from the thruster exit, while gradual broadening was found in the Xe I emission. Approximately 10% azimuthal nonuniformities were observed in the local Xe I and Xe II intensity profiles in the near-plume region (< 10 mm), which could not be quantitatively distinguished by analysis of the frontal photographic image. Three-dimensional Xe I and Xe II intensity profiles were also obtained in the plume region, and the differences in the structures of both emissions were visually confirmed.

Fractional Propagation of Short Light Pulses in Monomode Optical Fibers: Comparison of Beta Derivative and Truncated M- Fractional Derivative

2021 ◽  
Author(s):  
Muhammad Bilal Riaz ◽  
Adil Jhangeer ◽  
Jan Awrejcewicz ◽  
Dumitru Baleanu ◽  
Sana Tahir
Keyword(s):  
Fractional Derivative ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Three Dimensional ◽  
Soliton Solutions ◽  
The Other ◽  
Light Pulses ◽  
Free Parameters ◽  
Fractional Orders ◽  
Algebraic Technique

Abstract The present study is dedicated to the computation and analysis of solitonic structures of a nonlinear Sasa-Satsuma equation that comes in handy to understand the propagation of short light pulses in the monomode fiber optics with the aid of Beta Derivative and Truncated M- fractional derivative. We employ new direct algebraic technique for nonlinear Sasa-Satsuma equation to derive novel soliton solutions. A variety of soliton solutions are retrieved in trigonometric, hyperbolic, exponential, rational forms. The vast majority of obtained solutions represent the lead of this method on other techniques. The prime advantage of considered technique over the other techniques is that it provides more diverse solutions with some free parameters. Moreover, the fractional behavior of the obtained solutions is analyzed thoroughly by using two and three dimensional graphs. Which shows that for lower fractional orders i.e $\beta=0.1$, the magnitude of truncated M-fractional derivative is greater whereas for increasing fractional orders i.e $\beta=0.7$ and $\beta=0.99$, magnitude remains same for both definitions except for a phase shift in some spatial domain that eventually vanishes and two curves coincide.

Single-Shot Multiwavelength Imaging of Laser Plumes

1998 ◽  
Vol 52 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Matthew P. Nelson ◽  
Wendy C. Bell ◽  
Michael L. McLester ◽  
M. L. Myrick
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Ccd Camera ◽  
Chemical Imaging ◽  
Single Shot ◽  
Charge Coupled Device ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Optic Array ◽  
A Charge

A novel optical approach to single-shot chemical imaging with high spectroscopic resolution is described with the use of a prototype dimension-reduction fiber-optic array. Images are focused onto a 30 × 20 array of hexagonally packed 250 μm o.d. f/2 optical fibers that are drawn into a 600 × 1 distal array with specific ordering. The 600 × 1 side of the array is imaged with an f/2 spectrograph equipped with a holographic grating and a charge-coupled device (CCD) camera for spectral analysis. Software is used to extract the spatial/spectral information contained in the CCD images and de-convolute them into wavelength-specific reconstructed images or position-specific spectra that span a 190 nm wavelength space. “White light” zero-order images and first-order spectroscopic images of laser plumes have been reconstructed to illustrate proof-of-principle. Index Headings: Fiber optics; Chemical imaging; Spectroscopic imaging; Charged-coupled device (CCD); Laser-induced breakdown spectroscopy (LIBS).

scholarly journals Volumetric Diffuse Optical Tomography for Small Animals Using a CCD-Camera-Based Imaging System

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Zi-Jing Lin ◽  
Haijing Niu ◽  
Lin Li ◽  
Hanli Liu
Keyword(s):  
Imaging System ◽  
Optical Tomography ◽  
Small Animal Imaging ◽  
Three Dimensional ◽  
Diffuse Optical Tomography ◽  
Small Animal ◽  
Ccd Camera ◽  
Animal Imaging ◽  
Volumetric Images ◽  
Phantom Studies

We report the feasibility of three-dimensional (3D) volumetric diffuse optical tomography for small animal imaging by using a CCD-camera-based imaging system with a newly developed depth compensation algorithm (DCA). Our computer simulations and laboratory phantom studies have demonstrated that the combination of a CCD camera and DCA can significantly improve the accuracy in depth localization and lead to reconstruction of 3D volumetric images. This approach may present great interests for noninvasive 3D localization of an anomaly hidden in tissue, such as a tumor or a stroke lesion, for preclinical small animal models.

Designing high-resolution slow scan CCD-based TEM camera systems

1992 ◽  
Vol 50 (2) ◽  
pp. 946-947
Author(s):  
James F. Mancuso ◽  
William B. Maxwell ◽  
Russell E. Camp ◽  
Mark H. Ellisman
Keyword(s):  
Fiber Optics ◽  
Ccd Camera ◽  
High Energy ◽  
Phosphor Layer ◽  
X Ray ◽  
Light Production ◽  
Camera Systems ◽  
X Ray Imaging ◽  
Electron Image ◽  
Scintillating Fiber

The imaging requirements for 1000 line CCD camera systems include resolution, sensitivity, and field of view. In electronic camera systems these characteristics are determined primarily by the performance of the electro-optic interface. This component converts the electron image into a light image which is ultimately received by a camera sensor.Light production in the interface occurs when high energy electrons strike a phosphor or scintillator. Resolution is limited by electron scattering and absorption. For a constant resolution, more energy deposition occurs in denser phosphors (Figure 1). In this respect, high density x-ray phosphors such as Gd2O2S are better than ZnS based cathode ray tube phosphors. Scintillating fiber optics can be used instead of a discrete phosphor layer. The resolution of scintillating fiber optics that are used in x-ray imaging exceed 20 1p/mm and can be made very large. An example of a digital TEM image using a scintillating fiber optic plate is shown in Figure 2.

High-speed brightfield 3-D imaging and 3-D image analysis of thick and overlapped cell clusters in cytological preparations

1994 ◽  
Vol 52 ◽  
pp. 218-219
Author(s):  
Robert W. Mackin
Keyword(s):  
Image Analysis ◽  
High Speed ◽  
Three Dimensional ◽  
Image Data ◽  
Ccd Camera ◽  
Objective Lens ◽  
Array Processor ◽  
Vaginal Smears ◽  
Low Contrast ◽  
Computer Controlled

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.

scholarly journals Hyperspectral Three-Dimensional Fluorescence Imaging Using Snapshot Optical Tomography

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3652
Author(s):  
Cory Juntunen ◽  
Isabel M. Woller ◽  
Yongjin Sung
Keyword(s):  
Fourier Transform ◽  
3D Imaging ◽  
Optical Tomography ◽  
Three Dimensional ◽  
High Spectral Resolution ◽  
Functional Information ◽  
Fluorescent Beads ◽  
Different Depths ◽  
Projection Images ◽  
Imaging Performance

Hyperspectral three-dimensional (3D) imaging can provide both 3D structural and functional information of a specimen. The imaging throughput is typically very low due to the requirement of scanning mechanisms for different depths and wavelengths. Here we demonstrate hyperspectral 3D imaging using Snapshot projection optical tomography (SPOT) and Fourier-transform spectroscopy (FTS). SPOT allows us to instantaneously acquire the projection images corresponding to different viewing angles, while FTS allows us to perform hyperspectral imaging at high spectral resolution. Using fluorescent beads and sunflower pollens, we demonstrate the imaging performance of the developed system.

scholarly journals Imaging the Human Thyroid Using Three-Dimensional Diffuse Optical Tomography: A Preliminary Study

2021 ◽  
Vol 11 (4) ◽  
pp. 1670
Author(s):  
Tetsuya Mimura ◽  
Shinpei Okawa ◽  
Hiroshi Kawaguchi ◽  
Yukari Tanikawa ◽  
Yoko Hoshi
Keyword(s):  
Optical Tomography ◽  
Tumor Hypoxia ◽  
Three Dimensional ◽  
Diffuse Optical Tomography ◽  
Element Model ◽  
Needle Aspiration ◽  
Human Thyroid ◽  
Tissue Oxygen Saturation ◽  
Preliminary Study ◽  
First Time

Thyroid cancer is usually diagnosed by ultrasound imaging and fine-needle aspiration biopsy. However, diagnosis of follicular thyroid carcinomas (FTC) is difficult because FTC lacks nuclear atypia and a consensus on histological interpretation. Diffuse optical tomography (DOT) offers the potential to diagnose FTC because it can measure tumor hypoxia, while image reconstruction of the thyroid is still challenging mainly due to the complex anatomical features of the neck. In this study, we attempted to solve this issue by creating a finite element model of the human neck excluding the trachea (a void region). By reconstruction of the absorption coefficients at three wavelengths, 3D tissue oxygen saturation maps of the human thyroid are obtained for the first time by DOT.

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