The properties of output laser beam of hollow fiber

2003 ◽  
Author(s):  
Jiuhui Du
Keyword(s):  
Laser Beam ◽  
Hollow Fiber ◽  
Output Laser Beam ◽  
Output Laser

3D mapping of the output laser beam from a PDLC sample

2000 ◽  
Vol 27 (4) ◽  
pp. 477-482 ◽  
Author(s):  
L. Petti ◽  
P. Mormile ◽  
P. Musto ◽  
G. Ragosta ◽  
P. Villano ◽  
...  
Keyword(s):  
Laser Beam ◽  
3D Mapping ◽  
Output Laser Beam ◽  
Output Laser

scholarly journals Synchronization and Power Unit Controller for CO2 Laser Cable Marking System

2021 ◽  
Vol 15 ◽  
pp. 111-114
Author(s):  
S. Messaoud ◽  
F. Siserir ◽  
Y. Boucetta ◽  
M. Traiche ◽  
L. Henni ◽  
...  
Keyword(s):  
Laser Beam ◽  
Power Control ◽  
Power Unit ◽  
Co2 Laser ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Output Laser Beam ◽  
Control Circuits ◽  
Modulation Control ◽  
Output Laser

In this paper, we describe the design of the synchronization and power unit controller (SPUC) for CO2 laser cable marking system inline-processing. It is mainly composed of a synchronization and modulation control circuits. Power control of output laser beam is achieved by pulse width modulation (PWM). The synchronization between the CO2 laser, the rotating mask disk and the pivoting mirror is performed by a Lab VIEW based program and National Instruments (NI).

Thermische Resonatoreffekte in organischen Farbstofflasern / Thermal Resonator Effects in Oiganis Dye Lasers

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1272-1277 ◽  
Author(s):  
G. Zeidler
Keyword(s):  
Laser Beam ◽  
Thermal Lens ◽  
Angular Position ◽  
Tunable Laser ◽  
Beam Deflection ◽  
Laser Resonator ◽  
Dye Lasers ◽  
Pump Light ◽  
Output Laser Beam ◽  
Output Laser

Abstract Thermal resonator effects are studied in laser pumped organic dye lasers with the longitudinal pumping arrangement. If the distribution of the pump light is a Gaussion, a diverging lens is induced by the thermal gradient in the dye solution. This thermal lens was compensated by using a suitable resonator set-up with an adjustable telescope. Divergence and bandwidth of the tunable laser were reduced considerably by using the proper compensation. If the angular position of the pump beam is shifted, the axes of laser resonator and thermal lens are different, causing beam deflection and wavelength shifting of the output laser beam. Therefore, high stability and mode purity of the pump laser is important to get a well defined output laser beam.

Research on Focusing Spot Shape of High Power CO2 Laser

2010 ◽  
Vol 154-155 ◽  
pp. 1717-1721
Author(s):  
Xiao Feng Shang
Keyword(s):  
Laser Beam ◽  
High Power ◽  
Laser Power ◽  
Sampling Method ◽  
Head Turn ◽  
Turn Angle ◽  
Laser Head ◽  
Single Side ◽  
Output Laser ◽  
Axis Length

In order to meet the requirements of laser processing technology and quality, the laser bean oblique incidence technique is put forward and focusing laser spots with different shape and incident direction are realized. The relation between the output laser beam spot shape and laser power of high power CO2 laser is studied through the organic glass sampling method. The result indicates that the laser beam cross-section shape presents rectangle and the long-axis length of laser beam has nothing to do with the laser power changes, but the short-axis width increases with the laser power improving. The two-dimension rotary laser head is designed and the laser bean tilt incidence is realized. The formula of the relation between focusing spot coordinate in the processing plane and laser head turn angle, also swinging angle is deduced. The relation between the focusing spot shape and the laser power, defocusing amount, laser head turn and swinging angles is researched through the single-side gummed paper sampling method. The result indicates that the focusing laser spot form is affected by the parameters of laser power, defocusing amount, laser head turn and swinging angles.

scholarly journals Numerical investigation of the influence of wavefront distortion on the laser near-field characteristics

2017 ◽  
Vol 35 (4) ◽  
pp. 648-655 ◽  
Author(s):  
S. Li ◽  
Z. Lu ◽  
X. Fan ◽  
L. Ding
Keyword(s):  
High Frequency ◽  
Beam Quality ◽  
Near Field ◽  
Transmission Characteristics ◽  
Fresnel Number ◽  
Wavefront Distortion ◽  
Output Laser Beam ◽  
Output Laser ◽  
Field Modulation ◽  
Frequency Phase

AbstractThe effect of the initial phase distortion of the laser on near-field transmission characteristics in free space is investigated both numerically and theoretically. It is demonstrated and proposed that the near-field modulation and fluence contrast of the output laser beam are changing with the increase of both spatial low- and high-frequency wavefront distortion. The simulation results show that in order to ensure the beam quality in propagation, the Fresnel number should be controlled not <50 generally and the wavefront distortion should also be minimized by controlling both low- and high-frequency phase coefficient not larger than 0.6.

Experiment Study of Influence on Laser Beam Quality Induced by Thermal Lens Effect and Depolarization Effect

2010 ◽  
Vol 43 ◽  
pp. 670-674
Author(s):  
Xia Ye ◽  
Hong Bing Yao ◽  
Yan Qun Tong ◽  
Yong Kang Zhang ◽  
Ruo Xi Cao ◽  
...  
Keyword(s):  
Laser Beam ◽  
Thermal Lens ◽  
Thermal Effects ◽  
Beam Quality ◽  
Double Refraction ◽  
Lens Effect ◽  
Laser Beam Quality ◽  
Depolarization Effect ◽  
Output Laser ◽  
Thermal Lens Effect

For high power and repetitive Nd:Glass laser, there would appear serious thermal effect due to the significantly-enhanced pumping optical power density in laser rod, which would induce thermal double refraction, phase distortion, thermal focusing, thermal depolarization, etc. Thus, the laser output power and beam quality would be influenced severely. Influence of thermal lens effect and depolarization effect caused by thermal stress double refraction on laser beam were studied in this paper for high power and repetitive laser. In the experiment of thermal lens effect, change of the laser spot by thermal lens effect was recorded after a TEM00 He-Ne laser beam passing through the Nd:Glass rod pumped by Xe lamp, and the corresponding optical compensator was applied to eliminate the thermal lens effect to improve the beam quality. Configuration of polarizer was designed in our experiment to research the depolarization effect caused by thermal stress double refraction. First, emergent light distribution and loss factor caused by double refraction was calculated according to the theoretical model. Then the exiting cone-shaped polarized light intensity distribution was obtained through the experiment. It could be obtained from the experiments that thermal lens effect and depolarization effect caused by thermal double refraction would reduce the output laser beam quality to varied extents. As the number of laser pulses increased, thermal effects began to emerge and the output laser energy apparently decreased; when the thermal effects steadied, the output energy would be tending towards stability.

scholarly journals Effect of Turbulence on the Wavefront of an Ultrahigh Intensity Laser Beam

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Morgane Bellec ◽  
Alain Girard ◽  
Guillaume Balarac ◽  
Ulrich Bieder ◽  
François Millet ◽  
...  
Keyword(s):  
Laser Beam ◽  
Optical Pumping ◽  
Beam Quality ◽  
Turbulent Channel Flow ◽  
Channel Flows ◽  
Cryogenic Cooling ◽  
Laser Amplifiers ◽  
Cooling Channels ◽  
Laser Beam Quality ◽  
Output Laser

Abstract Ultrahigh intensity lasers face thermal management issues that limit their repetition rates. The key challenge is to efficiently evacuate the heat deposited in the amplifier by the optical pumping without impacting the output laser beam quality. The amplifier can have a multislab geometry where the laser beam crosses successive amplifying slabs and the cooling channels that separate them. This work investigates numerically how a cryogenic cooling of the amplifier by turbulent channel flows may affect the wavefront of the laser beam. To this end, large eddy simulations (LESs) representative of the amplifier cooling are performed using TrioCFD, a code developed by the CEA. First, validation simulations are carried out for heated channel flows, allowing comparisons to direct numerical simulation (DNS) results from the literature. Then, LESs of an open turbulent channel flow cooling two slabs are conducted using conjugated heat transfer between the solid and the fluid. The phase distortions, mean and fluctuations, induced by the inhomogeneous and turbulent temperature field are computed directly from the LES. A moderate although non-negligible effect of the turbulence on the laser wavefront was found. This optical effect increases when the slab heating increases. A comparison to the Sutton model, widely used in aero-optic studies, was performed, and its applicability was found limited for this problem. For the first time, TrioCFD is used to address the question of the beam impact of the cooling of laser amplifiers, and it has proven to be a valuable tool for such application.

Two-photon excitation microscopy in cellular biophysics

1995 ◽  
Vol 53 ◽  
pp. 62-63
Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers
Keyword(s):  
Confocal Microscopy ◽  
Laser Beam ◽  
Duty Cycle ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

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