The impact of the retarded Kerr effect on the laser pulses’ propagation in air

2015 ◽  
Vol 69 (3) ◽  
Author(s):  
Le Wang ◽  
Cunliang Ma ◽  
Xiexing Qi ◽  
Wenbin Lin
Keyword(s):  
Kerr Effect ◽  
Laser Pulses ◽  
The Impact

scholarly journals Single-molecule imaging with longer X-ray laser pulses

IUCrJ ◽  
2015 ◽  
Vol 2 (6) ◽  
pp. 661-674 ◽  
Author(s):  
Andrew V. Martin ◽  
Justine K. Corso ◽  
Carl Caleman ◽  
Nicusor Timneanu ◽  
Harry M. Quiney
Keyword(s):  
Single Molecule ◽  
Laser Pulses ◽  
Bragg Diffraction ◽  
Single Molecule Imaging ◽  
X Ray ◽  
Damage Models ◽  
Statistical Fluctuations ◽  
Damage Processes ◽  
The Impact ◽  
Serial Femtosecond Crystallography

During the last five years, serial femtosecond crystallography using X-ray laser pulses has been developed into a powerful technique for determining the atomic structures of protein molecules from micrometre- and sub-micrometre-sized crystals. One of the key reasons for this success is the `self-gating' pulse effect, whereby the X-ray laser pulses do not need to outrun all radiation damage processes. Instead, X-ray-induced damage terminates the Bragg diffraction prior to the pulse completing its passage through the sample, as if the Bragg diffraction were generated by a shorter pulse of equal intensity. As a result, serial femtosecond crystallography does not need to be performed with pulses as short as 5–10 fs, but can succeed for pulses 50–100 fs in duration. It is shown here that a similar gating effect applies to single-molecule diffraction with respect to spatially uncorrelated damage processes like ionization and ion diffusion. The effect is clearly seen in calculations of the diffraction contrast, by calculating the diffraction of the average structure separately to the diffraction from statistical fluctuations of the structure due to damage (`damage noise'). The results suggest that sub-nanometre single-molecule imaging with 30–50 fs pulses, like those produced at currently operating facilities, should not yet be ruled out. The theory presented opens up new experimental avenues to measure the impact of damage on single-particle diffraction, which is needed to test damage models and to identify optimal imaging conditions.

Kinetics of optical Kerr effect induced by picosecond laser pulses

1980 ◽  
Vol 34 (2) ◽  
pp. 269-272 ◽  
Author(s):  
J. Etchepare ◽  
G. Grillon ◽  
R. Muller ◽  
A. Orszag
Keyword(s):  
Kerr Effect ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Optical Kerr Effect ◽  
Picosecond Laser Pulses ◽  
Kinetics Of

scholarly journals Switching intense laser pulses guided by Kerr-effect-modified modes of a hollow-core photonic-crystal fiber

2005 ◽  
Vol 71 (2) ◽  
Author(s):  
D. A. Zheltikova ◽  
M. Scalora ◽  
A. M. Zheltikov ◽  
M. J. Bloemer ◽  
M. N. Shneider ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Kerr Effect ◽  
Laser Pulses ◽  
Intense Laser ◽  
Hollow Core ◽  
Crystal Fiber ◽  
Intense Laser Pulses

ALL-FIBRE SOURCE OF CONTINUOUS VARIABLE ENTANGLED LIGHT

2006 ◽  
Vol 20 (11n13) ◽  
pp. 1280-1286 ◽  
Author(s):  
A. NANDAN ◽  
M. SABUNCU ◽  
J. HEERSINK ◽  
O. GLÖCKL ◽  
G. LEUCHS ◽  
...  
Keyword(s):  
Kerr Effect ◽  
Beam Splitter ◽  
Laser Pulses ◽  
Quantum Correlations ◽  
Continuous Variable ◽  
Sagnac Interferometer ◽  
Detection Scheme ◽  
Fully Integrated ◽  
Simple Detection

We experimentally demonstrate the production of continuous variable entanglement of femto second laser pulses from an all-fibre asymmetric Sagnac interferometer exploiting the Kerr effect. Contrary to the experiment of Silberhorn et al. [Phys. Rev. Lett. 86, 4267 (2001)], the asymmetric coupler in the Sagnac loop is fully integrated in the fibre, making the source extremely compact, reliable and robust. Employing a simple detection scheme, comprising a beam splitter and two intensity detectors, we clearly observe quantum correlations of conjugate quadratures, hereby witnessing entanglement.

scholarly journals Fokker-Planck simulations of ultrashort-pulse laser-plasma interactions

1992 ◽  
Vol 10 (3) ◽  
pp. 461-471 ◽  
Author(s):  
L. Drska ◽  
J. Limpouch ◽  
R. Liska
Keyword(s):  
Heat Flux ◽  
Distribution Function ◽  
Laser Radiation ◽  
Electric Field ◽  
Electron Distribution ◽  
Electron Distribution Function ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Ultrashort Pulse Laser ◽  
The Impact

The interaction of ultrashort laser pulses with a fully ionized plasma is investigated in the plane geometry by means of numerical simulation. The impact of the space oscillations in the amplitude of the laser electric field on the shape of the electron distribution function, on laser beam absorption, and on electron heat transport is demonstrated. Oscillations in the absorption rate of laser radiation with the minima coincident to the maxima of the laser electric field lead to a further decrease in the absorption of laser radiation. Heat flux in the direction of increasing temperature in the underdense region is caused by the modification of the electron distribution function and by the density gradient. A limitation of heat flux to the overdense plasma isobserved with the flux limiter in range 0.03–0.08, growing moderately with the intensity 1014–1016 W/cm2 of the incident 1.2-ps laser pulse.

scholarly journals PRELIMINARY NUMERICAL ANALYSIS FOR THE ROLE OF SPEED ONTO LASER TECHNOLOGICAL PROCESSES

2019 ◽  
Vol 3 ◽  
pp. 137
Author(s):  
Lyubomir Lazov ◽  
Nikolay Angelov ◽  
Edmunds Teirumnieks ◽  
Erika Teirumnieka
Keyword(s):  
Laser Pulses ◽  
Temperature Fields ◽  
Laser Source ◽  
Electromagnetic Spectrum ◽  
Preliminary Assessment ◽  
Laser Marking ◽  
Technological Processes ◽  
The Impact ◽  
Power Densities

Studying the impact of speed on a number of laser processes such as marking, engraving, cutting, welding and others is crucial for the optimization of these technological processes. The processing speed, along with the frequency of laser pulses and their duration, also determines the time of action in the processing area and hence the absorbed quantity of electromagnetic energy. Based on numerical experiments with specialized software TEMPERATURFELD3D, the report analyzes the temperature variation in the processing area as a function of speed. The researches were analyzed for processing with two types of lasers emitting in the visible and infrared areas of the electromagnetic spectrum and two types of steels (tool and structural). From the course of the obtained temperature fields the dependence of temperature on the speed at two power densities was obtained. The obtained results help to make a preliminary assessment the speed work intervals for the processes as laser marking, laser engraving, laser cutting, laser welding and others. In this way, it is assisted in building an optimal concept for the passing of a particular technological process in function of the laser source, the material and the type of the technological operation.

scholarly journals Ultrafast polarization modulation of laser pulses at terahertz frequencies via optical Kerr effect

2018 ◽  
Vol 67 (23) ◽  
pp. 237801
Author(s):  
Lin Xian ◽  
Jin Zuan-Ming ◽  
Li Ju-Geng ◽  
Guo Fei-Yun ◽  
Zhuang Nai-Feng ◽  
...  
Keyword(s):  
Kerr Effect ◽  
Laser Pulses ◽  
Optical Kerr Effect ◽  
Polarization Modulation ◽  
Terahertz Frequencies

Surface modification of WC—3% Co hard alloy by powerful nanosecond ultraviolet laser pulses

2020 ◽  
pp. 11-14
Author(s):  
Yu. A. Zheleznov ◽  
◽  
T. V. Malinsky ◽  
S. I. Mikolutskiy ◽  
V. E. Rogalin ◽  
...  
Keyword(s):  
Hard Alloy ◽  
Radiation Energy ◽  
Laser Pulses ◽  
Incident Radiation ◽  
Impact Zone ◽  
Radiation Energy Density ◽  
Ultraviolet Laser ◽  
Focused Beams ◽  
The Impact

The surface quality of the WC—3% Co hard alloy after modification by focused beams of an ultraviolet laser has been investigated. At radiation energy density E ≥ 1.6 J / cm2, traces of melting with a size of 1—3 μm were found on the alloy surface in the impact zone. An increase in intensity of the incident radiation to E ≈ 6.2 J / cm2 leads to an increase in the concentration of cobalt on the surface from 7 to 10%, while the concentration of carbon decreases from 33 to 18%.

scholarly journals Occlusion of Cortical Ascending Venules Causes Blood Flow Decreases, Reversals in Flow Direction, and Vessel Dilation in Upstream Capillaries

2011 ◽  
Vol 31 (11) ◽  
pp. 2243-2254 ◽  
Author(s):  
John Nguyen ◽  
Nozomi Nishimura ◽  
Robert N Fetcho ◽  
Costantino Iadecola ◽  
Chris B Schaffer
Keyword(s):  
Blood Flow ◽  
Nearest Neighbor ◽  
Flow Direction ◽  
Cognitive Disorders ◽  
Laser Pulses ◽  
Vessel Diameter ◽  
Flow Speed ◽  
Femtosecond Laser Pulses ◽  
Brain Diseases ◽  
The Impact

The accumulation of small strokes has been linked to cognitive dysfunction. Although most animal models have focused on the impact of arteriole occlusions, clinical evidence indicates that venule occlusions may also be important. We used two-photon excited fluorescence microscopy to quantify changes in blood flow and vessel diameter in capillaries after occlusion of single ascending or surface cortical venules as a function of the connectivity between the measured capillary and the occluded venule. Clotting was induced by injuring the target vessel wall with femtosecond laser pulses. After an ascending venule (AV) occlusion, upstream capillaries showed decreases in blood flow speed, high rates of reversal in flow direction, and increases in vessel diameter. Surface venule occlusions produced similar effects, unless a collateral venule provided a new drain. Finally, we showed that AVs and penetrating arterioles have different nearest-neighbor spacing but capillaries branching from them have similar topology, which together predicted the severity and spatial extent of blood flow reduction after occlusion of either one. These results provide detailed insights into the widespread hemodynamic changes produced by cortical venule occlusions and may help elucidate the role of venule occlusions in the development of cognitive disorders and other brain diseases.

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