共查询到20条相似文献,搜索用时 16 毫秒
1.
M. Boutinguiza J. Pou F. Lusquios F. Quintero R. Soto M. Prez-Amor K. Watkins W. M. Steen 《Optics and Lasers in Engineering》2002,37(1)
Slate is a natural stone which has the characteristic that shows a well-developed defoliation plane, allowing to easily split it in plates parallel to that plane which are particularly used as tiles for roof building. At present, the manufacturing of slate is mostly manual, being noisy, powdery and unsafe for the worker. Thus, there is a need to introduce new processing methods in order to improve both the working conditions and the quality of the products made of slate.Following the previous work focused on the drilling and cutting of slate tiles using a Nd : YAG laser, we present in this paper the results of the work carried out to explore the possibilities to cut slate plates by using a CO2 laser. A 1.5 kW CO2 laser was used to perform different experiments in which, the influence of some processing parameters (average power, assist gas pressure) on the geometry and quality of the cut was studied. The results obtained show that the CO2 laser is a feasible tool for a successful cutting of slate. 相似文献
2.
Sung-Joon Park 《Optics & Laser Technology》2010,42(2):269-273
A microprocessor-based algorithm was developed to control the power supply to a CO2 laser using an AC-chopper method. This system was connected directly to a CO2 laser tube without the need for a dc-dc converter or the storage capacitance of a multilevel circuit. The typical CO2 laser power supply system had a full-bridge series resonant inverter or voltage multiplier. AC-to-AC converter schemes using zero voltage switching (ZVS) can be used efficiently and economically for low and medium power applications.This paper reports the performance characteristics of a symmetrical AC-chopper technology that can maintain the quality of the ac output of a CO2 laser tube, regardless of the amount of switching loss. The laser was operated to an output power, maximum system efficiency total gas mixture of 37.2 W, 92%, and CO2:N2:He=1:9:15, respectively. The laser system, AC-chopper power supply and its operation were examined. 相似文献
3.
A Teller–Landau six-temperature model describing the dynamic emission of single-mode TEA CO2 laser has been adapted. This model has been also used to describe the mechanism of obtaining relatively high-power output pulses from hybrid TE-TEA or CW-TEA CO2 laser consisting of high- and low-pressure sections. The suggested mathematical model allows to investigate the mechanism which limits the TEA oscillation to single longitudinal mode (SLM) due to the narrow gain bandwidth of low-pressure section, and also to study the effect of the laser input parameters on the smooth output laser pulse parameters. In addition, numerical solutions of non-linear rate equation system of the suggested model are quantitatively discussed. The solutions describe the radiation field intensity, the population inversion, and the energy transfer processes. The calculated values of maximum peak power, total energy in pulse, pulse width, etc. are in a very good agreement with the observed experimental values. 相似文献
4.
Multibeam CO2 lasers consist of a large number of closely packed parallel glass discharge tubes, all sharing a common plane parallel resonator. This paper describes construction and operation of a CW multibeam CO2 laser consisting 20 discharge tubes and cooled length of 1500 mm, delivering 1 kW power. A high-frequency pulser is used for producing preionization in all discharge sections for initiating the main DC discharge simultaneously in all discharge tubes. Plane parallel resonator consists of a plane ZnSe mirror of 90 mm diameter having 60% reflectivity and a gold-coated copper mirror of same diameter. This laser operates in waveguide regime and laser power is not critically sensitive to mirror misalignment. 相似文献
5.
A. Bertolini G. Carelli N. Ioli C. A. Massa J. C. S. Moraes A. Moretti F. Strumia 《International Journal of Infrared and Millimeter Waves》1997,18(4):779-783
Twenty-five new laser lines have been obtained in the wavelength region from 155 to 830 μm by optically pumping the CD2Cl2 (deuterated dichloromethane) molecule with a CW CO2 laser having a tunability range of 300 MHz. The wavelength, polarization relative to that of CO2 pumping radiation, and offset relative to the CO2 center frequency were determined for all of the new lines and some other already known laser emissions. For all of them we
give also the relative intensity and the optimum pressure of operation.
Permanent address: Depto de Física e Química da FEIS — UNESP 15.378-000 Ilha Solteira-SP, Brazil 相似文献
6.
Aniruddha Kumar J.P. NilayaD.J. Biswas R.B. BhattMohd. Afzal J.P. PanakkalH.S. Kamath 《Applied Surface Science》2011,257(16):7263-7267
Pulsed laser assisted removal of uranium dioxide and thorium dioxide particulates from stainless steel surface have been studied using a TEA CO2 laser. Decontamination efficiency is measured as a function of laser fluence and number of pulses. Threshold fluence for the removal of UO2 particulates has been found to be lower than that required for the removal ThO2 particulates. Usage of a ZnSe substrate, that is transparent to the laser wavelength used here, enabled us to decouple the cleaning effect arising out of absorption in the particulates from that in the substrate and has contributed towards understanding the mechanism responsible for cleaning. The experimental observations are also corroborated by simple theoretical calculations. 相似文献
7.
A theoretical analysis of phase-locking in a multi-channel radial array CO2 laser is presented. The concepts are based on the theories of injection phase-locking and matrix optics. The mutual optical coupling occurring within the central region is demonstrated by theoretical deduction. Interrelated graphs of the coupling coefficient and the distance between the coupling position and the cavity mirror are calculated by numerical simulation. The results of the analysis are in accord with experimental results. 相似文献
8.
Bimal K. Deka 《International Journal of Infrared and Millimeter Waves》1985,6(12):1285-1294
The thresholds for CO2 laser induced breakdown and their variation with pulse width have been measured at various pressures for Ar, N2 and an 8/1/1 laser mixture of He/CO2/N2 using 3–40 ns duration pulses. These measurements indicate that excited state production plays a dominant role in determining the threshold for nanosecond duration pulses. This has been confirmed by the good agreement obtained between the measured and theoretical thresholds. 相似文献
9.
T. Okada S. Inoue T. Ohga K. Muraoka M. Akazaki 《International Journal of Infrared and Millimeter Waves》1985,6(9):883-892
A D2O laser has been developed for collective Thomson scattering measurements of ion temperature in high temperature plasmas. A pulse duration and a spectral width of a high power D2O laser has been successfully controlled for this purpose, by using a TEA CO2 laser injection-locked by an etalon-tuned TEA CO2 laser as a pump source. 相似文献
10.
A. K. Nath T. Reghu C. P. Paul M. O. Ittoop P. Bhargava 《Optics & Laser Technology》2005,37(4):469-335
A transverse flow transversely excited (TFTE) CW CO2 with a maximum output power about 15 kW has been developed. This is excited by pulser sustained DC discharge applied between a pair of multi-pins anodes and a common tubular cathode. Though the laser power in convective cooled CO2 laser scales proportionally with the volumetric gas flow, it did not increase in this laser when the volumetric gas flow was increased by increasing the electrode separation keeping the flow velocity constant. The discharge voltage too remained almost unchanged with increase of the electrode separation. These observations are explained considering the electrical discharge being controlled by ionization instability. Laser materials processing applications often demand programming facilities for laser power modulation. A four-stage cascaded multilevel DC–DC converter-based high-frequency switch mode power supply has been developed to modulate the output power of the laser. Laser was operated up to 15 kW output power in four different modes viz. continuous wave mode, pulse periodic mode, single shot mode and processing velocity-dependent power mode with 1.2 kHz modulation bandwidth. We describe briefly the laser system, the SMPS, and the temporal behavior of laser beam. 相似文献
11.
A four-temperature model has been applied on a fast axial flow, longitudinal discharge CO2 laser. Using Runge–Kutta method, a set of differential equations of the model is numericaly solved. These equations describe the operation of the laser with certain ratio 1:3:6 of the mixture CO2:N2: He and average output power of 550 W.The temporal behaviour of the output power and photon density was obtained. The effects of kinetic temperature, coupled mirror reflectivity, gas flow speed, and cavity loss on the output power were studied.Calculated output power was compared with its measured value taken from experiment and a good agreement was observed. 相似文献
12.
This paper presents the results of the calculation of the parameters of the active medium of a fast-axial-flow CO2 laser using numerical methods in the framework of a one-dimensional approximation of the set of continuity equations, Bernoulli equation, equation of gas state, energy equation and multi-temperature rate equations with regard to diffusion for the gas flow in the cylindrical discharge tube. The spatial distribution of the small-signal gain and gas temperature along the gas flow direction have been calculated for a given set of initial conditions, namely, gas flow velocity, gas pressure and the tube diameter. In addition, the dependence of small-signal gain, the asymmetric stretch vibrational temperature of CO2 (T3) and the gas temperature on the discharge current were studied. 相似文献
13.
Three pressures of gases (CO2, N2 and He) added into CO2 laser tube are optimized for obtaining maximal laser output power by applying a genetic algorithm and solving the CO2 laser kinetics equations. After the optimization, the laser power is increased by 96% as compared with a non-optimal case. 相似文献
14.
Temperature distributions along various hollow waveguides are fully analysed experimentally when the waveguides are excited by CO2 laser light. It is shown that the temperature decreases in an oscillatory manner along the waveguides due to the interference effect of guided modes. The distributors are well explained by a theory developed previously. 相似文献
15.
We have developed a 1-D spatially-dependent model and simulation code to study the dynamics of TEA CO2 lasers. In this paper we will discuss the motivation for developing the model and present the simulation details. We have compared and verified the simulation results with the previous 0-D model, and with the measurements of a TEA CO2 laser. With spatial resolution, the 1-D simulation is in better agreement with experimental results compared with the existing 0-D model. 相似文献
16.
Aniruddha Kumar J. Padma Nilaya M.B. Sai Prasad P. Raote D.J. Biswas 《Optics & Laser Technology》2008,40(1):223-225
A helium-free mini TEA CO2 laser has been operated at a repetition rate of 100 Hz wherein the gas re-circulatory loop consisting of heat exchanger and catalytic converter, mandatory for conventional repetitive operation of such lasers, have been totally dispensed with. The laser utilized inexpensive molecular gases alone that were simply flown out transversely through the inter-electrode region by an open gas flow system. The active medium was energized by making use of a spiker-sustainer excitation scheme. At this repetition rate, the laser produced an average power of 3.50 W. 相似文献
17.
CO2泵浦源是光泵气体太赫兹激光器的核心器件之一,其性能直接关系到太赫兹激光器的工作稳定性。CO2泵浦源一般由闪耀光栅作为全反射尾镜,构成特殊的光栅腔实现波长的选支输出。采用传输矩阵的特征向量法对光栅谐振腔的腔内光场模式进行了理论分析与数值模拟,计算了光栅腔的一系列本征模式及相应的衍射损耗。结果表明光栅腔的腔内模式特性等效于一个平凹腔,而对于大菲涅尔数的光栅腔, Littrow波长的附近支线也可能具有衍射损耗较低的低阶模,可能优先于Littrow波长的高阶模起振,导致光栅腔的波长选择性降低。 相似文献
18.
Rationality and feasibility of axisymmetric folded-combined cavity CO2 laser which is reported in this paper have been proved by principle experiments. The laser lays a foundation to manufacture higher power CO2 lasers whose output power can easily reach 1 kW. Faculas at different positions in free space and facula of nine beams which pass through the beam focusing optics have been obtained. Analyses of the experimental results are made. These analyses lay a foundation for beam transformation, transmission and shaping. 相似文献
19.
The present study examines the drilling and heating of a bone due to pulsed CO2 laser irradiation. To obtain temperature profiles inside and at the surface of the bone, electron-kinetic and Fourier theories are used. The study is extended to include an experimental investigation into the measurement of the penetration speed. This is achieved using a fibre-optic system. In order to reduce the degree of burning around the hole side, helium was used as the assisting gas during drilling. It is found that the penetration speeds predicted from the theory are in good agreement with the experimentally obtained values. 相似文献
20.
采用10.6 μupm 的 CO2激光, 对单次激光脉冲辐照修复熔石英存在的烧蚀采用大光斑钝化去除. 经过辐照修复的区域置于前表面测试初始损伤阈值, 结果表明调制造成的损伤得到了一定程度的抑制; 辐照区域置于后表面修复后 熔石英的初始损伤阈值超过了基底的初始损伤阈值. 实验观察到了应力分布外扩, 同时明显减弱. 对损伤增长的测试说明, 经过激光熔融辐照后的损伤点, 当应力释放以后, 损伤扩展初期表现出指数增长趋势, 后期随着辐照次数的增加, 损伤增长不再明显, 并且趋于恒定值. 相似文献