Laser beam focal spot analysis

2002 ◽  
Author(s):  
A.B. Katrich ◽  
A.A. Katrich ◽  
I.A. Priz
Keyword(s):  
Laser Beam ◽  
Focal Spot ◽  
Spot Analysis

scholarly journals 1178 J, 527 nm near diffraction limited laser based on a complete closed-loop adaptive optics controlled off-axis multi-pass amplification laser system

2021 ◽  
Vol 9 ◽  
Author(s):  
Deen Wang ◽  
Xin Zhang ◽  
Wanjun Dai ◽  
Ying Yang ◽  
Xuewei Deng ◽  
...  
Keyword(s):  
Laser Beam ◽  
Adaptive Optics ◽  
Closed Loop ◽  
Focal Spot ◽  
Beam Quality ◽  
Laser System ◽  
Diffraction Limit ◽  
Kdp Crystal ◽  
Main Amplifier

Abstract A 1178 J near diffraction limited 527 nm laser is realized in a complete closed-loop adaptive optics (AO) controlled off-axis multi-pass amplification laser system. Generated from a fiber laser and amplified by the pre-amplifier and the main amplifier, a 1053 nm laser beam with the energy of 1900 J is obtained and converted into a 527 nm laser beam by a KDP crystal with 62% conversion efficiency, 1178 J and beam quality of 7.93 times the diffraction limit (DL). By using a complete closed-loop AO configuration, the static and dynamic wavefront distortions of the laser system are measured and compensated. After correction, the diameter of the circle enclosing 80% energy is improved remarkably from 7.93DL to 1.29DL. The focal spot is highly concentrated and the 1178 J, 527 nm near diffraction limited laser is achieved.

scholarly journals Self-Focusing of Hermite-Cosh-Gaussian Laser Beams in Plasma under Density Transition

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Manzoor Ahmad Wani ◽  
Niti Kant
Keyword(s):  
Laser Beam ◽  
Plasma Density ◽  
Focal Spot ◽  
Beam Width ◽  
Spot Size ◽  
Laser Beams ◽  
Equation Approach ◽  
Focal Spot Size ◽  
Self Focusing ◽  
Small Spot

Self-focusing of Hermite-Cosh-Gaussian (HChG) laser beam in plasma under density transition has been discussed here. The field distribution in the medium is expressed in terms of beam-width parameters and decentered parameter. The differential equations for the beam-width parameters are established by a parabolic wave equation approach under paraxial approximation. To overcome the defocusing, localized upward plasma density ramp is considered, so that the laser beam is focused on a small spot size. Plasma density ramp plays an important role in reducing the defocusing effect and maintaining the focal spot size up to several Rayleigh lengths. To discuss the nature of self-focusing, the behaviour of beam-width parameters with dimensionless distance of propagation for various values of decentered parameters is examined by numerical estimates. The results are presented graphically and the effect of plasma density ramp and decentered parameter on self-focusing of the beams has been discussed.

scholarly journals XUV and Soft X-Ray Radiation from Laser Produced Plasmas as Laboratory Spectroscopic Sources

1984 ◽  
Vol 86 ◽  
pp. 212-212
Author(s):  
P. Gohil ◽  
M.L. Ginter ◽  
T.J. McIlrath ◽  
H. Kapoor ◽  
D. Ma ◽  
...  
Keyword(s):  
High Resolution ◽  
Laser Beam ◽  
Spectral Region ◽  
Focal Spot ◽  
Laser Energy ◽  
Diffraction Limit ◽  
High Resolution Spectroscopy ◽  
Diode Array ◽  
X Ray ◽  
Pin Photodiode

Laser produced plasmas have been shown to be excellent sources for applications in the XUV and soft X-ray spectral region. We are using a 550 mj, 25 ns (FWHM) ND:YAG laser operating at a repetition rate of 10 Hz to produce plasmas above rotatable solid targets. The focal spot of the laser beam with a 31 cm lens was measured to be 170 μm (approximately twice the diffraction limit), using a diode array having a 170 μm resolution. Broadband output in the soft X-ray region was studied using a windowless PIN photodiode with an A1203 surface covered with a polyethylene filter with transmission between 44 Å and 120 Å. Results are presented for the source’s soft X-ray intensity for several elements as a function of laser energy, focus and driving wavelength, as are preliminary results using the source for high resolution spectroscopy and for soft X-ray lithography.

The Influence of High-Frequency Phase of Laser Wavefront on the Distribution of Focal Spot

2014 ◽  
Vol 644-650 ◽  
pp. 1433-1437
Author(s):  
Fu Xing Fu
Keyword(s):  
Laser Beam ◽  
Surface Properties ◽  
High Frequency ◽  
Focal Spot ◽  
Laser Intensity ◽  
Side Lobe ◽  
Laser Beams ◽  
Damage Effect ◽  
Frequency Phase ◽  
Peak Value

When laser beam is effected on the material, the surface properties of material can be damaged, and the damage effect is different for the different laser beams. Nevertheless, the distribution of laser intensity is influenced by the proportion of high-frequency phase in wavefront. By researching the propagation character of wavefront phase, the relation of high-frequency phase and laser intensity is given in this paper. The results show that the focal spot increases gradually with the increase of the proportion of high-frequency phase, the peak value of intensity decreases obviously, and the number of side lobe increases observably.

Effect of optical diffraction on laser heating of a field emitter

1986 ◽  
Vol 64 (1) ◽  
pp. 111-117 ◽  
Author(s):  
E. S. Robins ◽  
M. J. G. Lee ◽  
P. Langlois
Keyword(s):  
Electromagnetic Field ◽  
Plane Wave ◽  
Laser Beam ◽  
Laser Heating ◽  
Focal Spot ◽  
Incident Beam ◽  
Optical Diffraction ◽  
Field Emitter ◽  
Complicated Geometry ◽  
Direction Of Polarization

The wavelength of the illuminating radiation used in studies of photofield emission is comparable to the diameter of the shank of the field emitter. Under these conditions, diffraction is expected to play an important role in determining the absorption of energy from the electromagnetic field. The complicated geometry of the field emitter has so far prevented an exact calculation of this effect. By considering the diffraction of a plane wave by an idealized model of a field emitter, we have calculated the absorption of energy from an incident focussed laser beam. Calculations based on the present results yield accurate predictions of the magnitude of the temperature rise and its dependence on the position of the focal spot and on the direction of polarization of the incident beam.

The Design and Simulated Analysis of Laser Beam-Shaping System for the Flow Cytometry

2014 ◽  
Vol 635-637 ◽  
pp. 1114-1117
Author(s):  
Guo Dong Liu ◽  
Xi Ying Hao ◽  
Zhen Huang ◽  
Zhong Ren
Keyword(s):  
Flow Cytometry ◽  
Laser Beam ◽  
Optical System ◽  
Focal Spot ◽  
Chromatic Aberration ◽  
Beam Shaping ◽  
Laser Beam Shaping ◽  
Actual Design ◽  
Shaping System ◽  
Simulated Analysis

As for the requirement of size and energy distribution of focal spot in the laser detection area, this paper designs a laser beam-shaping system of flow cytometry. The 640nm red diode laser and 488nm blue solid laser which are arranged vertically are used as the excitation source. The emergent ray of two lasers is combined by beam splitter, and the combined beam is focused on the screen through two orthogonal cylindrical lens. The focal spot is compressed by doublet lens which is also used to eliminate chromatic aberration of focal spot. Applying ZEMAX software to optimize the whole optical system, the simulated results meet fully the actual experiment for individual blood cells, and it has certain theoretical significance for actual design of optical system about flow cytometry.

Improving the efficiency of the SLM-process by adjusting the focal spot diameter of the laser beam

2021 ◽  
Vol 2021 (5) ◽  
pp. 18-23
Author(s):  
S.V. Adjamskyi ◽  
◽  
G.A. Kononenko ◽  
R.V. Podolskyi ◽  
◽  
...  
Keyword(s):  
Laser Beam ◽  
Focal Spot ◽  
Spot Diameter ◽  
Focal Spot Diameter

Relation between second-order moment radius of focal spot and near field distribution of laser beam

2011 ◽  
Vol 23 (6) ◽  
pp. 1449-1453 ◽  
Author(s):  
高学燕 Gao Xueyan ◽  
苏毅 Su Yi ◽  
叶一东 Ye Yidong ◽  
关有光 Guan Youguang
Keyword(s):  
Laser Beam ◽  
Field Distribution ◽  
Focal Spot ◽  
Near Field ◽  
Second Order ◽  
Order Moment

Diffractive phase element for shrinking focal spot diameter: Design, fabrication, and application to laser beam lithography

2001 ◽  
Vol 8 (6) ◽  
pp. 416-421
Author(s):  
Yusuke Ogura ◽  
Jun Tanida ◽  
Yoshiki Ichioka ◽  
Yoshiaki Mokuno ◽  
Katsunori Matsuoka
Keyword(s):  
Laser Beam ◽  
Focal Spot ◽  
Spot Diameter ◽  
Diffractive Phase Element ◽  
Focal Spot Diameter
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