The method of cross-section for controling laser beam spot image shape

2013 ◽  
Author(s):  
L. I. Tymchenko ◽  
Yu. F. Kutaev ◽  
N. I. Petrovskyi ◽  
N. I. Kokryatskaya ◽  
A. E. Denysova ◽  
...  
Keyword(s):  
Laser Beam ◽  
Cross Section ◽  
Beam Spot ◽  
Image Shape ◽  
Spot Image

scholarly journals Sources of Variability in the Response of Labeled Microspheres and B Cells during the Analysis by a Flow Cytometer

2021 ◽  
Vol 22 (15) ◽  
pp. 8256
Author(s):  
Adolfas K. Gaigalas ◽  
Yu-Zhong Zhang ◽  
Linhua Tian ◽  
Lili Wang
Keyword(s):  
B Cells ◽  
Laser Beam ◽  
Cross Section ◽  
Mean Fluorescence Intensity ◽  
Numerical Aperture ◽  
Flow Cytometer ◽  
Fluorescence Signal ◽  
Minor Importance ◽  
Reliable Measure ◽  
The Mean

A stochastic model of the flow cytometer measurement process was developed to assess the nature of the observed coefficient of variation (CV%) of the mean fluorescence intensity (MFI) from a population of labeled microspheres (beads). Several sources of variability were considered: the total number of labels on a bead, the path through the laser beam, the optical absorption cross-section, the quantum yield, the numerical aperture of the collection optics, and the photoelectron conversion efficiency of the photomultiplier (PMT) cathode. The variation in the number of labels on a bead had the largest effect on the CV% of the MFI of the bead population. The variation in the path of the bead through the laser beam was minimized using flat-top lasers. The variability in the average optical properties of the labels was of minor importance for beads with sufficiently large number of labels. The application of the bead results to the measured CV% of labeled B cells indicated that the measured CV% was a reliable measure of the variability of antibodies bound per cell. With some modifications, the model can be extended to multicolor flow cytometers and to the study of CV% from cells with low fluorescence signal.

scholarly journals Development of micromirror-based laser line generator

2021 ◽  
Author(s):  
Farzad Hossein Nia
Keyword(s):  
Laser Beam ◽  
System Design ◽  
Laser Line ◽  
Beam Spot ◽  
Optical System Design ◽  
Straight Line ◽  
Laser Module ◽  
Design Software ◽  
Working Distance ◽  
Conventional Laser

A laser line generator projects a straight line on an object and is widely used for alignment, identification, barcode reading, etc. Conventional laser line generators make use of cylindrical and Powell lenses that convert a laser beam spot into a line. Because of a fixed fan angle, however, the length and brightness of the generated line depends on the working distance between the laser module and object. In this project, using the optical system design software Zemax and engineering CAD software Solidworks, a micromirror based laser line generator is designed and fabricated. The performance of the fabricated micromirror based laser line generator is tested and compared with the performance of a conventional laser line generator. The results show that the length and brightness of image line can be kept constant by the designed generator.

scholarly journals INFLUENCE OF LASER BEAM PROFILE ON LIGHT SCATTERING BY HUMAN SKIN DURING PHOTOMETRY BY ELLIPSOIDAL REFLECTORS

2018 ◽  
Vol 9 (1) ◽  
pp. 56-65 ◽  
Author(s):  
M. A. Bezuglyi ◽  
N. V. Bezuglaya ◽  
S. Kostuk
Keyword(s):  
Monte Carlo Simulation ◽  
Adipose Tissue ◽  
Laser Beam ◽  
Human Skin ◽  
Cross Section ◽  
Beam Profile ◽  
Laser Beam Profile ◽  
Reflected Light ◽  
Section Profile ◽  
Cross Section Profile

The correct accounting of laser emitter parameters for improvement of diagnostic authenticity of methods of optical biomedical diagnostic is important problem for applied biophotonic tasks. The purpose of the current research is estimation of influence of energy distribution profile in transversal section of laser beam on light scattering by human skin layers at photometry by ellipsoidal reflectors.Biomedical photometer with ellipsoidal reflectors for investigation of biological tissue specimens in transmitted and reflected light uses laser probing radiation with infinitely thin, Gauss-type and uniform cross-section profile. Distribution of beams with denoted profiles, which consist of 20 million photons with wavelength 632.8 nm, was modeled by using of Monte-Carlo simulation in human skin layers (corneous layer, epidermis, derma and adipose tissue) of various anatomic thickness and with ellipsoidal reflectors with focal parameter equal to 16.875 mm and eccentricity of 0.66.The modeling results represent that illuminance distribution in zones of photometric imaging is significantly influenced by the laser beam cross-section profile for various thickness of corneous layer and epidermis in transmitted and reflected light, and also derma in reflected light. Illuminance distribution for adipose tissue in reflected and transmitted light, and also derma in transmitted light, practically do not depend of laser beam profile for anatomic thicknesses, which are appropriate for human skin on various sections of body.There are represented results of modified Monte-Carlo simulation method for biomedical photometer with ellipsoidal reflectors during biometry of human skin layers. For highly scattered corneous layer and epidermis the illumination of middle and external rings of photometric images changes depending from the laser beam profile for more than 50 % in transmitted and 30 % in reflected light. For weakly scattering skin layers (derma and adipose layer) the influence of profile can be observed only for derma in reflected layer and is equal not more than 15 %. 

Formation of given field distribution in laser-beam cross section

1984 ◽  
Vol 27 (5) ◽  
pp. 411-413
Author(s):  
V. B. Korshikov ◽  
P. R. Lakhno ◽  
V. N. Rozhdestvin
Keyword(s):  
Laser Beam ◽  
Cross Section ◽  
Field Distribution ◽  
Beam Cross Section

Measurement of focal length based on laser-beam-spot tracking system using diffractive beam sampler

Measurement ◽  
2018 ◽  
Vol 122 ◽  
pp. 135-140 ◽  
Author(s):  
Binh Xuan Cao ◽  
Phuong Le Hoang ◽  
Sanghoon Ahn ◽  
Jeng-o Kim ◽  
Heeshin Kang ◽  
...  
Keyword(s):  
Laser Beam ◽  
Focal Length ◽  
Tracking System ◽  
Beam Spot

An Improved Calculation of the Multiphoton Bremsstrahlung Process in the Presence of a Laser Beam

1977 ◽  
Vol 30 (1) ◽  
pp. 33
Author(s):  
Rama Acharya ◽  
Man Mohan
Keyword(s):  
Laser Beam ◽  
Cross Section ◽  
Coulomb Field ◽  
Final States ◽  
The Cross ◽  
Bremsstrahlung Process

It has been noted previously that analyses of free-free transitions in the presence of an ion are appreciably affected by neglecting the Coulomb field of the ion at infinity. We have therefore made here an improved calculation of the cross section for the multiphoton bremsstrahlung process by taking account of the Coulomb field in the initial and final states.

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