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Journal articles on the topic 'Impulsi laser'

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Author: Grafiati

Published: 11 March 2023

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1

Phipps, C. R., and M. M. Michaelis. "LISP: Laser impulse space propulsion." Laser and Particle Beams 12, no. 1 (March 1994): 23–54. http://dx.doi.org/10.1017/s0263034600007217.

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It is not often that a new form of transportation suddenly appears and replaces what was hitherto regarded as mankind's only realistic option. In space and upper atmosphere transportation, chemical rockets have held center stage for over half a century. Tsiokolvsky's ideas led to Wernher von Braun's V2, which in turn led to the Soyuz, Apollo, and Ariane programs and the Space Shuttle. But recently theoretical and computational studies as well as a few initial experiments have pointed to a new option: laser impulse space propulsion (LISP). This may offer a more efficient and less ecologically damaging means of putting payloads into orbit. The world high-power laser community is well suited to following and aiding developments in LISP, though most practical research is still at an embryonic level. Obviously an effort of the size required to develop a laser-driven low-earth-orbit (LEO) launcher would require a multinational commitment. LISP could then be regarded as a parallel challenge to those of achieving ICF rriicrofusion yield and of improving X-ray lasers, especially in the “water window.” Any physicist or engineer involved with the latter projects would find many points in common with the former. It therefore seems appropriate to briefly review the progress made in LISP and also to communicate some recent results from high-power laser-matter experiments that have lead to conceptual designs.

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2

Chen, Peiyu, Mostafa Hosseini, and Aydin Babakhani. "An Integrated Germanium-Based THz Impulse Radiator with an Optical Waveguide Coupled Photoconductive Switch in Silicon." Micromachines 10, no. 6 (May 31, 2019): 367. http://dx.doi.org/10.3390/mi10060367.

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This paper presents an integrated germanium (Ge)-based THz impulse radiator with an optical waveguide coupled photoconductive switch in a low-cost silicon-on-insulator (SOI) process. This process provides a Ge thin film, which is used as photoconductive material. To generate short THz impulses, N++ implant is added to the Ge thin film to reduce its photo-carrier lifetime to sub-picosecond for faster transient response. A bow-tie antenna is designed and connected to the photoconductive switch for radiation. To improve radiation efficiency, a silicon lens is attached to the substrate-side of the chip. This design features an optical-waveguide-enabled “horizontal” coupling mechanism between the optical excitation signal and the photoconductive switch. The THz emitter prototype works with 1550 nm femtosecond lasers. The radiated THz impulses achieve a full-width at half maximum (FWHM) of 1.14 ps and a bandwidth of 1.5 THz. The average radiated power is 0.337 μ W. Compared with conventional THz photoconductive antennas (PCAs), this design exhibits several advantages: First, it uses silicon-based technology, which reduces the fabrication cost; second, the excitation wavelength is 1550 nm, at which various low-cost laser sources operate; and third, in this design, the monolithic excitation mechanism between the excitation laser and the photoconductive switch enables on-chip programmable control of excitation signals for THz beam-steering.

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3

موسى, عصام. "اختيار نظام لحام صفائح من النيكل بالليزر وتأثير بارامترات هذا النظام في أبعاد الدرزات اللحامية الناتجة." FES Journal of Engineering Sciences 3, no. 1 (November 6, 2008): 10. http://dx.doi.org/10.52981/fjes.v3i1.73.

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The effect of Laser welding system’s parameters on the dimensions of Nickel welded joint with thickness not more than (1.0 mm) was studied. The principal parameters of impulsed Laser in this case , which had influence on the welded spot’s dimensions ( spot’s diameter D & penetration h ) , are : the power of Laser beam , impulse time & the focusing distance of Laser beam to the welded joint. It was resulted that the values of dimension ( h ) increased (with high accelerating ) by the increasing of Laser beam’s power & impulse time & the decreasing of focusing distance , but the values of dimension D increased very slowly by the changes of above – mentioned parameters , and as result the values of melting form’s coefficient (Ψ = D / h ) decreased & reached the minimum when the melting penetration was about 1.0 mm ( the thiclness of Nickel plate ) . The micro-structure studying of cross sections in the welded joints showed that if the power of Laser beam was so high that the tmperature of welded spot was so high than the meting point of welded metal, the latest one obsorbed a lot of gases from the surrounded atmosphere and variuos defects were noticed in this weld metal. So, it’s too important to use a sheilding gas ( like Argon ) to improve the reaction of these gases with the weld metal .

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4

Arestova, N. N., N. S. Egiyan, T. B. Kruglova, and R. V. Kalinichenko. "Prevention of IOL Laser Damage after YAG Laser Destruction in Children with Secondary Cataract." Ophthalmology in Russia 18, no. 2 (July 5, 2021): 245–52. http://dx.doi.org/10.18008/1816-5095-2021-2-245-252.

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Background. In recent years there is a tendency to more often admission in our institution children with multiple IOL damage caused by laser treatment of secondary cataract operated at local hospitals.Purpose. To analyze the causes of laser damage to IOL in children underwent YAG laser destruction of secondary cataract and find best ways to prevent them.Patients and methods. We analyzed the frequency of acrylic IOL damage after YAG-laser destruction in 593 children with congenital, posttraumatic and postuveal cataract at age from 6 months to 17 years (one third of patients were less than 3 years old). All laser operations were performed on identical YAG-laser, by the same protocol and by one surgeon.Results. We confirmed that main reliable prevention factor of damage to IOL in children is the precise focus of laser beam. In past 10 years in our institution, we managed to decrease frequency of laser damage to IOL in children with secondary cataract in 4.5 times due to performing operations under general anesthesia (43.8 % in 2007–2008, 65.8 % in 2018). Thus, decreasing frequency from 5.9 % to 1.3 % in the same age group of patients.Conclusion. To achieve the effective prevention of laser damage to IOL in cases of YAG laser destruction of secondary cataract it is essential to use general anesthesia in following conditions: children 5 or below age, non-contact children of older age, children with nystagmus, CNS pathology, psychomotor development delay. It is unacceptable to perform this operations without general anesthesia in children that can’t fix the gaze. Furthermore it is important to use contact lenses to fix the eyes of a child, select the individual less invasive method and technique of laser operation, utilize single short impulses with minimal effective energy, thoroughly follow standard safe energy modes (impulse energy shouldn’t be more than 2.4 mJ, impulse number should be not more than 100).

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5

Nalisko, Mykola, Valerii Sobolev, Dmytro Rudakov, and Nataliia Bilan. "Assessing safety conditions in underground excavations after a methane-air mixture explosion." E3S Web of Conferences 123 (2019): 01008. http://dx.doi.org/10.1051/e3sconf/201912301008.

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A technique for evaluation of shock wave impulse after a methane-air mixture explosion is elaborated. The numerical model developed in previous studies has been verified in the laboratory by using laser initiation of explosives and measuring the pressure impulses of explosion products on a ballistic pendulum. To evaluate the mechanical impulse the functional correlations between its magnitude, the swing angle, and the pendulum characteristics have been derived analytically. The reliability of experimental results is ensured by calibrating the sensor that measures the pendulum swing angle and estimating the impulse measurement errors caused by specifics of angle measurements by a digital voltmeter, pendulum axis friction, and the pauses between measurements. Testing the developed technique to evaluate the shock wave impact showed satisfactory consistency of experimental and theoretical results with the momentum deviation below 9%, which confirms model applicability and correct reproducibility of the shock wave propagation process.

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6

Sęk, Piotr, and Szymon Tofil. "Laser Cold Ablation as a Cutting Edge Method of Forming Silicon Wafers Used in Solar Cells." Advanced Materials Research 874 (January 2014): 113–18. http://dx.doi.org/10.4028/www.scientific.net/amr.874.113.

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The article shows experimental results of mild cutting of surface layers of polycrystalline silicon photovoltaic cells with a picoseconds UV laser. Current technology makes a strong point on reliability and quality of photovoltaic microprocessing. Using short impulse lasers guarantee best quality of cutting edge without burr, HAZ and changing crystalline structure of the base material, with is very important due to electrical conductivity of the solar cell.

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7

Phipps, Claude. "Lisk-Broom: A laser concept for clearing space debris." Laser and Particle Beams 13, no. 1 (March 1995): 33–41. http://dx.doi.org/10.1017/s0263034600008831.

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So-called “space junk” forced a change of plan for a recent Shuttle mission. However, ground-based lasers with atmospheric-turbulence-compensating beam directors represent a singularly effective method of de-orbiting space junk, because they use cheap Earth-based power, and because they lend themselves to rapid retargeting. Plasma physics and lasertarget interaction theory dictate the laser parameters for a particular mission. We will discuss a practical laser system and beam director with 20-kW average power at 0.5-µm wavelength that is capable of clearing most low-Earth-orbit objects with mass less than 100 kg in about 4 years. This is a special application of the Laser Impulse Space Propulsion (LISP) concept, by which objects are propelled in space by the ablation jet produced on their surface by a remote laser.

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8

Yin, Gui Min, Zhan Guo Li, and Meng Li. "The Optimization Study about Technological Parameters of YAG Laser Precision Cutting Stainless Sheet." Advanced Materials Research 652-654 (January 2013): 2369–73. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.2369.

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Using high power Nd3+:YAG pulse laser for precision cutting stainless sheet, study the effects of the laser cutting technological parameters on quality of cutting surface and joint-cutting width. The data of single factor experiment proved： With the increasing of scanning velocity, the joint-cutting width decreased; the width increased with the increasing of scanning velocity, laser current, impulse frequency and impulse width; the increasing of impulse frequency may improve the processing quality and ultimate cutting speed; the data of two-factors experiment proved: when the output power and impulse width are fixed, the impulse frequency will be increased, the joint-cutting width will be decreased; when the output power and impulse frequency are fixed, the impulse width will be increased, the joint-cutting width will be decreased.

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9

Linkevičius, Linas. "Membership of NATO is the Impulse for Reforms." Lithuanian Annual Strategic Review 1, no. 1 (July 18, 2003): 7–15. http://dx.doi.org/10.47459/lasr.2003.1.1.

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10

Ye, Ji Fei, Guang Yu Wang, and Dian Kai Wang. "Measurement of Laser Ablation Micro Impulse Using the Torsion Pendulum Interferometry." Advanced Materials Research 301-303 (July 2011): 1078–82. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.1078.

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A method is described for measuring the micro impulse induced by the laser ablation. This method is based upon the torsion pendulum interferometry technique. The method measures the micro impulse through the detection of the swinging angle of torsion pendulum. The swinging angle is obtained by the laser differential interferometry. For the 10-4~10-7 magnitude micro-impulse, It could be the important measurement method in the research of micro laser plasma thruster (mLPT). The results of some preliminary experiments are presented with detailed reference to experiment methodology and accuracy. The measurement technique is well suited to cases seeking the measurement of mN×s magnitude micro-impulse.

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11

Pałys, Tomasz, Krzysztof Murawski, and Artur Arciuch. "System sterowania optycznego z wykorzystaniem elementów AR." Przegląd Teleinformatyczny 5 (23), no. 4 (December 31, 2017): 35–52. http://dx.doi.org/10.5604/01.3001.0012.9715.

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W artykule zaproponowano metodę kodowania wiązki lasera, którą zastosowano do sterowania systemem rzeczywistości rozszerzonej. Eksperymenty wykonano, stosując laser czerwony emitujący falę o długości  = 650 nm i mocy P = 3 mW. Celem badań było sprawdzenie opracowanych metod modulacji i demodulacji kodowanego sygnału laserowego oraz zbadanie wpływu parametrów, takich jak: czas trwania impulsu lasera, rozdzielczość obrazu pozyskiwanego z kamery, liczba rejestrowanych klatek na sekundę na wynik demodulacji sygnału optycznego. Uzyskane wyniki pokazały, że proponowana metoda kodowania zapewnia transmisję niezbędnej liczby informacji w pojedynczej wiązce lasera (nie mniej niż 36 symboli przy skuteczności dekodowania wynoszącej 99,9%). Opracowany sposób kodowania umożliwia, na podstawie analizy sekwencji obrazów wideo, oddziaływanie na przebieg symulacji realizowanej w rzeczywistości rozszerzonej, w tym również rozróżnienie graczy i podejmowanych przez nich akcji. Jest to istotny postęp względem systemów interakcji stosowanych do wpływania na rzeczywistość rozszerzoną.

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12

Li, Mingyu, Jifei Ye, Chentao Mao, Sibo Wang, and Chenghao Yu. "Study on impulse and ablation of aluminum irradiated by millimeter spot of short pulse laser." Journal of Physics: Conference Series 2108, no. 1 (November 1, 2021): 012096. http://dx.doi.org/10.1088/1742-6596/2108/1/012096.

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Abstract Aluminum is a high performance working medium for laser ablation micro propulsion. In order to study the propulsion performance and ablation of aluminum under millimeter light spot irradiation, a short pulse Nd: YAG laser with wavelength of 1064nm and pulse width of 8NS was used to irradiate aluminum target in atmosphere. The impulse, the impulse coupling coefficient and the ablation morphology of the aluminum target produced by 6 kinds of millimeter-level light spots are measured. The experimental results show that when the spot diameter reaches 6-7mm, the increasing trend of impulse and impulse coupling coefficient of aluminum target with the increase of laser energy slows down; A large number of ablation products began to accumulate on the surface of the target pit.

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13

Zamytskiy, E. A., A. V. Zolotarev, E. V. Karlova, N. Yu Il’yasova, and A. S. Shirokanev. "Comparative quantitative assessment of the placement and intensity of laser spots for treating diabetic macular edema." Russian Journal of Clinical Ophthalmology 21, no. 2 (2021): 58–62. http://dx.doi.org/10.32364/2311-7729-2021-21-2-58-62.

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Aim: to compare the uniformity and adequacy of the placement of laser spots after mono-impulse and pattern photocoagulation for diabetic macular edema (DME). Patients and Methods: fundus photographs of 83 patients (121 eyes) taken right after retinal photocoagulation for DME were analyzed. Group 1 included images of 63 eyes after pattern photocoagulation and group 2 included images of 58 eyes after mono-impulse photocoagulation. Laser burns of varying intensity based on LʹEsperance scale (including grade 0 burns that were not seen on fundus photos) were calculated. Grade 2 burns were considered optimal. The number of non-optimal laser burns placed on retinal hemorrhages, blood vessels, hard exudates or healthy retina was calculated. The uniformity of the position of laser spots was assessed by calculating the standard deviation from the average distance between laser spots. Results: the percentage of laser spots of optimal intensity was 31.85% in group 1 and 25.15% in group 2. The percentage of non-optimally placed laser spots was 24.34% in group 1 and 7.99% in group 2. The uniformity of the placement was good in both groups (8.16 pixels and 8.44 pixels, respectively), no significant difference was reported (p=0.0591). Conclusion: pattern photocoagulation is preferable for DME compared to mono-impulse photocoagulation to provide adequate intensity of laser burns. Meanwhile, mono-impulse regimen provides more precise placement of laser spots. However, both conventional techniques are not effective enough due many intrinsic drawback, i.e., many laser spots are non-optimal in terms of intensity or placement. In routine practice, these drawbacks are outweighed by the skills and experience of laser surgeon. Planned precise placement of laser spots and the introduction of techniques of more precise preventive adjustment of energy level for each laser spot will contribute to the maximum effect of photocoagulation for DME. Further studies on personalized precise laser photocoagulation will improve the quality and efficacy of the treatment of macular edema. Keywords: diabetic retinopathy, diabetic macular edema, mono-impulse photocoagulation, pattern photocoagulation, navigated photocoagulation. For citation: Zamytskiy E.A., Zolotarev A.V., Karlova E.V. et al. Comparative quantitative assessment of the placement and intensity of laser spots for treating diabetic macular edema. Russian Journal of Clinical Ophthalmology. 2021;21(2):58–62. DOI: 10.32364/2311-7729- 2021-21-2-58-62.

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14

Mengfan Cheng, Mengfan Cheng, and Hanping Hu Hanping Hu. "Theoretical investigations of impulsive synchronization on semiconductor laser chaotic systems." Chinese Optics Letters 10, no. 10 (2012): 101901–4. http://dx.doi.org/10.3788/col201210.101901.

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15

Phipps, C., J. Luke, D. Funk, D. Moore, J. Glownia, and T. Lippert. "Laser impulse coupling at 130fs." Applied Surface Science 252, no. 13 (April 2006): 4838–44. http://dx.doi.org/10.1016/j.apsusc.2005.07.079.

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16

Svéda, Mária, Dóra Janovszky, K. Tomolya, J. Sólyom, G. Buza, and A. Roósz. "Nanostructure Layer Formation on Cu-Zr-Al Alloy during Laser Remelting." Materials Science Forum 729 (November 2012): 272–77. http://dx.doi.org/10.4028/www.scientific.net/msf.729.272.

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This paper reports laser remelting of crystalline Cu based alloys in order to produce amorphous layer on the surface. The as prepared Cu based master alloy ingots were imbedded in a metallic sinking with Wood metal to assure the good thermal conductivity during the laser treatment. The laser remelting of a thin surface layer and a subsequent rapid cooling of it was performed using impulse and continuous mode of Nd:YAG laser. In respectively the impulse mode the laser power and the interaction time were 1.5; 2 kW and 20÷100 ms. In the continuous mode the laser power was 2 kW, and the laser scan speed was 80÷120 mm/s. The characterization of the microstructure of surface layer was performed by XRD, scanning electron microscopy and microhardness measurements.

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17

Kuzin, V. V., S. N. Grigoriev, and V. N. Ermolin. "Impulse laser effect on graphitized surface of Y‒TZP-ceramics." NOVYE OGNEUPORY (NEW REFRACTORIES), no. 3 (April 30, 2019): 58–63. http://dx.doi.org/10.17073/1683-4518-2019-3-58-63.

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Using the original technique, the role of the graphite layer under impulse laser effect on the surface of ceramics based on tetragonal zirconia, partially stabilized by yttrium oxide (Y‒TZP-ceramics), was studied. It has been established that surface graphitization increases the fraction of absorbed laser radiation, as a result of which heating, melting and evaporation of Y‒TZP-ceramics occur under less intense modes, which favorably affects the use of impulse laser radiation to modify its surface. Ill. 6. Ref. 18.

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18

Palla, Daniele, and Gabriele Cristoforetti. "Laser–Accelerated Plasma–Propulsion System." Applied Sciences 11, no. 21 (October 29, 2021): 10154. http://dx.doi.org/10.3390/app112110154.

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In this paper, the laser-accelerated plasma–propulsion system (LAPPS) for a spacecraft is revisited. Starting from the general properties of relativistic propellants, the relations between specific impulse, engine thrust and rocket dynamics have been obtained. The specific impulse is defined in terms of the relativistic velocity of the propellant using the Walter’s parameterization, which is a suitable and general formalism for closed–cycle engines. Finally, the laser-driven acceleration of light ions via Target Normal Sheath Acceleration (TNSA) is discussed as a thruster. We find that LAPPS is capable of an impressive specific impulse Isp in the 105 s range for a laser intensity I0≃1021W/cm2. The limit of Isp≲104 s, which characterizes most of the other plasma-based space electric propulsion systems, can be obtained with a relatively low laser intensity of I0≳1019W/cm2. Finally, at fixed laser energy, the engine thrust can be larger by a factor 102 with respect to previous estimates, making the LAPPS potentially capable of thrust-power ratios in the N/MW range.

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19

Wang, Dian Kai, and Yan Ji Hong. "Interaction of High Power Laser with Carbon Doped PVC." Applied Mechanics and Materials 249-250 (December 2012): 983–86. http://dx.doi.org/10.4028/www.scientific.net/amm.249-250.983.

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To measure the propulsion characters of PVC(poly vinyl chloride) doped with carbon ablated by high power density laser, torsion pendulum is used to measure the micro impulse. Laser interference is used to detect the vibration of the pendulum which is caused by the ablating jet. The measurement error is 2.6 according to the calibration. Nd:YAG laser is used as the laser source. Mettler-Toledo XS105DU analytical balance is used to measure the ablated mass. The results indicate that the performance of PVC+2C is better as an alternate target. Both the specific impulse(Isp) and energy transforming efficiency() increase with laser power density(I0), while momentum coupling coefficient(Cm) decreases. The maximum measured Cm is 557N/W. Isp and  reach to 204s and 46 respectively.

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20

Qianqian Shi, Qianqian Shi, Yan Zhang Yan Zhang, Kunpeng Wang Kunpeng Wang, Chenglin Wang Chenglin Wang, and Peng Zhao Peng Zhao. "Experimental research on impulse coupling effect of a multi-pulse laser on an aluminum target." Chinese Optics Letters 16, no. 12 (2018): 121401. http://dx.doi.org/10.3788/col201816.121401.

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21

Vavin, V. V., I. I. Nazhmudinov, Kh Sh Davudov, T. I. Garashchenko, B. Kh Davudova, K. M. Magomedova, and M. Yu Khoranova. "Features of CO₂-laser application in surgical treatment of chronic cicatrical stenoses of the larynx." Meditsinskiy sovet = Medical Council, no. 6 (May 27, 2020): 108–13. http://dx.doi.org/10.21518/2079-701x-2020-6-108-113.

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The aim of the review is to identify current possibilities of carbon dioxide laser application in microsurgical treatment of chronic laryngeal cicatricial stenoses. Currently, laser endolaryngeal surgeries are one of the main standards in surgical treatment of patients with this laryngeal pathology, including when providing high-tech assistance. Various types of lasers and methods of surgical treatment of the larynx are used. The choice of these methods is primarily determined by the opinion of the operating surgeon. The review highlights the principles of laser surgery in general, and when using carbon dioxide laser in particular. The use of micromanipulators makes it possible to combine the work of carbon dioxide laser with the operating microscope, affecting target tissues noninvasively with maximum precision. This technology makes it possible to expand the range of surgical manipulations in endolaryngeal surgeries. The main operating modes of the carbon dioxide laser, applicable for different clinical situations, such as power, impulse, laser power density (PD) are considered. In addition, the combination of a micromanipulator with an operating microscope allows the use of additional techniques aimed at preventing restenosis, such as the use of microflaps, submucosal laryngeal cicatricial tissue vaporization. The possibilities of the recurrence of cicatricial stenosis by different variants of stenting are presented. The risk of complications of this technique is not higher than in other types of larynx laser surgeries, and with proper preventive measures can be minimized. In the review, possible complications, both early and late, measures of their prophylaxis, as well as ways to eliminate their consequences are analyzed in detail.

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22

Киселева, Т. А., Т. А. Коротаева, and В. И. Яковлев. "Моделирование лазерного энергоподвода в газовый поток." Письма в журнал технической физики 45, no. 7 (2019): 29. http://dx.doi.org/10.21883/pjtf.2019.07.47533.17592.

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AbstractThe results of numerical modeling of laser energy supply in a supersonic flow are presented. In contrast to the common approach, in the new calculation model, not only the absorbed power is taken into account, but also the plasma breakdown impulse in the domain of emission focusing does. The value of the impulse is determined using the model of radiation absorption behind the front of the laser-supported detonation wave. An analysis of the results is presented.

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23

Dushko, V. G., L. V. Levash, V. S. Lysenko, Yu G. Ptushinsky, V. S. Rad’ko, O. A. Rosnovsky, and V. B. Samoylov. "Pyroelectric Joulemeter of Impulse Laser Radiation." Nauka ta innovacii 6, no. 5 (September 30, 2010): 50–54. http://dx.doi.org/10.15407/scin6.05.050.

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24

Markevich, M. I., D. V. Zhigulin, V. I. Zhuravleva, V. F. Stelmakh, and A. M. Chaplanov. "Impulse laser radiation on basalt fabric." Polymer materials and technologies 4, no. 3 (2018): 51–56. http://dx.doi.org/10.32864/polymmattech-2018-4-3-51-56.

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25

Bhargava, P., M. Kumar, H. Kumar, P. Pandit, R. Pandey, and A. K. Nath. "Impulse coupling in laser-driven microtargets." Pramana 62, no. 4 (April 2004): 923–32. http://dx.doi.org/10.1007/bf02706140.

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26

Shevchenko, Yuriy, Roman Volotovskiy, Egor Vasiliev, Alexander Perzhu, Dmitrii Kapitan, Alexey Rybin, Konstantin Soldatov, et al. "Monte Carlo Simulations of the Fast Remagnetization Process in Fept Granular Films." Solid State Phenomena 312 (November 2020): 281–87. http://dx.doi.org/10.4028/www.scientific.net/ssp.312.281.

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We utilize the Metropolis algorithm to obtain statistical averages of the domain wall length in a FePt granular structure after remagnetization is performed by an ultrashort polarized laser impulse. We propose and check the cluster-size-based order parameter, which along with magnetization, shows the domain wall length, and as a consequence, the average cluster size in the system. We treat the inverse Faraday effect as an external directed magnetic field and show impulse time- and laser power- dependent estimates within the Heisenberg model.

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27

Phipps, C. R., G. Albrecht, H. Friedman, D. Gavel, E. V. George, J. Murray, C. Ho, W. Priedhorsky, M. M. Michaelis, and J. P. Reilly. "ORION: Clearing near-Earth space debris using a 20-kW, 530-nm, Earth-based, repetitively pulsed laser." Laser and Particle Beams 14, no. 1 (March 1996): 1–44. http://dx.doi.org/10.1017/s0263034600009733.

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When a large piece of space debris forced a change of flight plan for arecent U.S. Space Shuttle mission, the concept that we are trashing space as well as Earth finally attained broad public awareness. Almost a million pieces of debris have been generated by 35 years of spaceflight, and now threaten long-term space missions. The most economical solution to this problem is to cause space debris items to reenter and burn up in the atmosphere. For safe handling of large objects, it is desired to do this on a precomputed trajectory. Due to the number, speed, and spacial distribution of the objects, a highly agile source of mechanical impulse, as well as a quantum leap in detection capability are required. For reasons we will discuss, we believe that the best means of accomplishing these goals is the system we propose here, which uses a ground-based laser system and active beam phase error correcting beam director to provide the impulse, together with a new, computer-intensive, very high-resolution optical detection system to locate objects as small as 1 cm at 500-km range. Illumination of the objects by the repetitively pulsed laser produces a laser-ablation jet that gives the impulse to de-orbit the object. A laser of just 20-kW average power and state-of-the-art detection capabilities could clear near-Earth space below 100-km altitude of all space debris larger than 1 cm but less massive than 100 kg in about 4 years, and all debris in the threatening 1–20-cm size range in about 2 years of continuous operation. The ORION laser would be sited near the Equator at a high altitude location (e.g., the Uhuru site on Kilimanjaro), minimizing turbulence correction, conversion by stimulated Raman scattering, and absorption of the 530-nm wavelength laser beam. ORION is a special case of Laser Impulse Space Propulsion (LISP), studied extensively by Los Alamos and others over the past 4 years.

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Duan, Buren, Haonan Zhang, Lizhi Wu, Zuohao Hua, Zijing Bao, Ning Guo, Yinghua Ye, and Ruiqi Shen. "Acceleration characteristics of laser ablation Cu plasma in the electrostatic field." European Physical Journal Applied Physics 93, no. 2 (February 2021): 20802. http://dx.doi.org/10.1051/epjap/2021200349.

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As a new concept of space propulsion system, laser-ablation propulsion has attracted more and more attention due to its characteristics of low power consumption, high specific impulse, variable and controllable thrust. With an aim to further raise up the movement velocity of plasma, we combine the laser with high-voltage electrostatic field to accelerate the Cu plasma induced by laser ablation. To demonstrate the acceleration characteristics of plasma under different electric field intensity, the plasma conductivity, plasma shockwave intensity and plasma plume movement process were tested using parallel electrode plate device, self-made torsion pendulum impulse test bench and high-speed ICCD camera. The results showed that the conductive current and impulse formed by the plasma obviously increased under the applied electric field. The images captured by high-speed ICCD camera showed the plasma cross-sectional area was 0.194 mm2 at 900 ns and 0.217 mm2 at 1600 ns when the electric field intensity was 0 V/mm. With the electric field intensity increased to 30 V/mm, the plasma cross-sectional area elevated to 0.280 mm2 at 900 ns and 0.288 mm2 at 1600 ns. The acquisitions prove that the idea of this paper is feasible and favorable, which provide a theoretical basis for the combination of laser ablation propulsion and electric field.

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Sizov, Sergei, Vladimir Tabakov, and Aleksey Chikhranov. "Functional parameters of the cutting process of the cutting tool with multilayer coatings after pulsed laser treatment." MATEC Web of Conferences 224 (2018): 01087. http://dx.doi.org/10.1051/matecconf/201822401087.

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The paper presents the results of functional parameters of the cutting process using the multilayer coated cutting tool based on nitrides of titanium, zirconium, niobium and aluminum – TiN-TiZrN-TiZrAlN, TiN-TiZrN-TiZrNbAlN before and after the impulse laser processing. It was demonstrated that the impulse laser processing shortens the overall contact length between chips and the front surface, decreases the chips shorting coefficient, cutting force components and the heat flow capacity at the front surface. The shortening of the overall contact length gives some boost to the rate of heat flows along the front and rear surfaces. This fact decreases contact temperatures in comparison with the instrument without the pulsed laser treatment. It was demonstrated that the shortening of the overall contact length between chips and the front surface after the pulsed laser treatment adjusts temperature filed isotherms and stress isobars in the tool cutting wedge to the rear surface and the cutting edge.

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Peng, Yu Feng, Long Jin, and Si Hong Lin. "Laser Impulse Detection System Based on Piezoelectric Film Sensor." Advanced Materials Research 529 (June 2012): 130–34. http://dx.doi.org/10.4028/www.scientific.net/amr.529.130.

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In order to use relatively simple approach to detect the laser impulse chose the polymer organic thin-film piezoelectric sensor with high sensitivity, wide dynamic range, good frequency band response and other good characteristics, designed the subsequent amplifying and detecting circuit. The sensor converted non-electricity quantity of laser impact to measurable electricity quantity via piezoelectric effect and the amplifier circuit. After the detection system processing, the final output signal was displayed by the oscilloscope and made simple analysis of the results.

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Yu Chenghao, 于程浩, 周伟静 Zhou Weijing, 常浩 Chang Hao, 陈一夫 Chen Yifu, and 郭威 Guo Wei. "纳秒激光毫米级光斑辐照典型金属材料冲量耦合特性." Infrared and Laser Engineering 50, no. 8 (2021): 20200390. http://dx.doi.org/10.3788/irla20200390.

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HOSOKAWA, Yoichiroh. "Single Cell Manipulation Utilizing Femtosecond Laser Impulse." Journal of the Japan Society for Precision Engineering 84, no. 11 (November 5, 2018): 892–95. http://dx.doi.org/10.2493/jjspe.84.892.

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OYAMA, Takumi, Keiji HAGIWARA, Hideyuki HORISAWA, and Kota FUKUDA. "Impulse Vector Characteristics of Laser Ablation Thrusters." TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 12, ists29 (2014): Pb_85—Pb_90. http://dx.doi.org/10.2322/tastj.12.pb_85.

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Volkova, L. V., E. A. Averyanova, R. N. Nurmukhametov, and S. P. Kabanov. "Laser photochemical modification of poly-p-xylylene." Izvestiya MGTU MAMI 4, no. 2 (January 20, 2010): 108–12. http://dx.doi.org/10.17816/2074-0530-69663.

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The spectral luminescence properties of poly-p-xylylene films irradiated by impulse UV- laser were studied. It was shown that the UV-laser irradiation to leads to the effective formation of new optical emission centers in the polymer chain. The fluorescence band of these centers is found over the visible range.

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Cao, Xiao Bing, Yi Cen Xu, Chang Ying Rui, and Zheng Ya Shan. "Simulation of Trajectory Correction for an Impulse Control Mortar Projectile with a Strapdown Laser Seeker." Applied Mechanics and Materials 367 (August 2013): 377–81. http://dx.doi.org/10.4028/www.scientific.net/amm.367.377.

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Aiming at improving the precision of mortar projectiles, an impulse control mechanism is proposed in this paper. The guidance uses a four-quadrant strapdown laser seeker to detect the intended target and utilizes impulse thrusters to correct the terminal trajectory. Based on the analysis of impulse forces and impulse moments, the 6-DOF equations for the trajectory under control are deduced. Also, the model of the seeker’s acquisition area is established. Numerical simulations of typical corrected trajectories are carried out with the computer programs developed in C code. The results indicate that the impulse thrusters can improve impact point performance effectively. The models and the control algorithms are applicable to the simulation and calculation for similar projectiles.

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Wang Chenglin, 王成林, 张艳 Zhang Yan, and 王鲲鹏 Wang Kunpeng. "Effect of Impulse Coupling Coefficient on Impulse Vector of Laser Irradiating Space Debris." Laser & Optoelectronics Progress 53, no. 12 (2016): 121404. http://dx.doi.org/10.3788/lop53.121404.

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Jiang, Su Qin, Ai Hui Liu, Xiao Xue Wang, and Zhong Chen. "The Bending Forming Mechanism of Copper Alloy by Different Lasers." Advanced Materials Research 968 (June 2014): 142–45. http://dx.doi.org/10.4028/www.scientific.net/amr.968.142.

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By FEA method, the bending of the copper alloy thin-plates by continuous laser forming (CLF) and pulse laser forming (PLF) was studied. Based on the analysis of dynamic change and steady distribution for the fields of temperature, stress/strain and displacement, the forming mechanism and rule of copper alloy by different laser modes were revealed. The whole deformation of PLF was the additive effect of all impulse action, while CLF mainly was the result of thermal stress. To get the same deformation, laser pulse energy is about 6 times of the continuous laser，CLF is suitable for larger deformation demands, and PLF is more seemly for micro-forming.

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Rinaudo, Carlo N., Michael C. Schubert, William V. C. Figtree, Christopher J. Todd, and Americo A. Migliaccio. "Human vestibulo-ocular reflex adaptation is frequency selective." Journal of Neurophysiology 122, no. 3 (September 1, 2019): 984–93. http://dx.doi.org/10.1152/jn.00162.2019.

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The vestibulo-ocular reflex (VOR) is the only system that maintains stable vision during rapid head rotations. The VOR gain (eye/head velocity) can be trained to increase using a vestibular-visual mismatch stimulus. We sought to determine whether low-frequency (sinusoidal) head rotation during training leads to changes in the VOR during high-frequency head rotation testing, where the VOR is more physiologically relevant. We tested eight normal subjects over three sessions. For training protocol 1, subjects performed active sinusoidal head rotations at 1.3 Hz while tracking a laser target, whose velocity incrementally increased relative to head velocity so that the VOR gain required to stabilize the target went from 1.1 to 2 over 15 min. Protocol 2 was the same as protocol 1, except that head rotations were at 0.5 Hz. For protocol 3, head rotation frequency incrementally increased from 0.5 to 2 Hz over 15 min, while the VOR gain required to stabilize the target was kept at 2. We measured the active and passive, sinusoidal (1.3Hz) and head impulse VOR gains before and after each protocol. Sinusoidal and head impulse VOR gains increased in protocols 1 and 3; however, although the sinusoidal VOR gain increase was ~20%, the related head impulse gain increase was only ~10%. Protocol 2 resulted in no-gain adaptation. These data show human VOR adaptation is frequency selective, suggesting that if one seeks to increase the higher-frequency VOR response, i.e., where it is physiologically most relevant, then higher-frequency head movements are required during training, e.g., head impulses. NEW & NOTEWORTHY This study shows that human vestibulo-ocular reflex adaptation is frequency selective at frequencies >0.3 Hz. The VOR in response to mid- (1.3 Hz) and high-frequency (impulse) head rotations were measured before and after mid-frequency sinusoidal VOR adaptation training, revealing that the mid-frequency gain change was higher than high-frequency gain change. Thus, if one seeks to increase the higher-frequency VOR response, where it is physiologically most relevant, then higher-frequency head movements are required during training.

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Sushchenia, Н. A., and L. N. Marchenko. "Subthreshold micro-impulse laser coagulation of retinal detachment in children." Doklady BGUIR 18, no. 8 (December 27, 2020): 89–96. http://dx.doi.org/10.35596/1729-7648-2020-18-8-89-96.

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Retinal detachment in children often requires multiple revisions. Despite active surgical treatment, subretinal fluid can persist for a long time in the macular region of the fundus. This leads to a decrease in visual acuity after surgery and an unsatisfactory functional result of treatment. In the absence of central vision, children develop amblyopia and secondary strabismus. Reoperations increase the risk of complications. Threshold laser coagulation leads to thermal burns of all layers of the retina with the formation of chorioretinal adhesion, which ensures adhesion of the retinal layers, but irreversibly damages the retinal neuroepithelium. Аs a result, the use of threshold laser coagulation in the macular zone is limited. The method of subthreshold micropulse diode laser ablation (STDLA) was developed on the basis of a clinical examination of 44 pediatric patients of the pediatric ophthalmology department of the Minsk Regional Children's Clinical Hospital, whose level of subretinal fluid in the posterior pole of the eyes remained for a long time after extrascleral surgery for retinal detachment. The proposed exposure parameters provide a selective effect on the cells of the retinal pigment epithelium with laser radiation in the micropulse mode without irreversible thermal denaturation of photoreceptors and without damage to the neuroepithelium in order to stimulate the resorption of subretinal fluid and correct transudative disorders. As a result, the adhesion of the retinal photoreceptor layer to the pigment epithelium is restored. The effectiveness of the method is confirmed by a decrease or complete disappearance of subretinal fluid, adhesion of neuroepithelium according to optical coherence tomography and leads to an increase in visual acuity. The proposed method made it possible to optimize the treatment of children with retinal detachment, to improve the anatomical and functional outcomes of treatment, which is of medical and socio-economic importance.

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Lopez, Abraham, Haley N. Strong, Kendra I. McGlothen, Dustin J. Hines, and R. Jacob Baker. "A Compact Avalanche-Transistor-Based Pulse Generator for Transcranial Infrared Light Stimulation (TILS) Experiments." Instruments 6, no. 3 (June 23, 2022): 20. http://dx.doi.org/10.3390/instruments6030020.

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A pulse generator using an avalanche transistor operating in current-mode second breakdown driving a 780 nm laser diode is reported. The laser diode is mounted on the skull of a mouse and used in transcranial infrared light stimulation (TILS) experiments. The output current pulse width is approximately 2 ns in an attempt to generate a true impulse-like optical pulse excitation for the TILS experiments.

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Shen, Nan, Jeff D. Bude, Sonny Ly, Wesley J. Keller, Alexander M. Rubenchik, Raluca Negres, and Gabe Guss. "Enhancement of laser material drilling using high-impulse multi-laser melt ejection." Optics Express 27, no. 14 (July 2, 2019): 19864. http://dx.doi.org/10.1364/oe.27.019864.

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Sinko, John E., and Don A. Greogry. "CO2 Laser Ablation Impulse Generation with Polymer Propellants." Journal of Propulsion and Power 27, no. 5 (September 2011): 1121–30. http://dx.doi.org/10.2514/1.b34072.

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43

Chang Hao, Jin Xing, and Chen Zhao-Yang. "Numerical simulation of nanosecond laser ablation impulse coupling." Acta Physica Sinica 62, no. 19 (2013): 195203. http://dx.doi.org/10.7498/aps.62.195203.

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HOSOKAWA, Yoichiroh, Takanori IINO, Man HAGIYAMA, and Akihiko ITO. "Intercellular Adhesion Strength Analysis Utilizing Femtosecond Laser Impulse." Seibutsu Butsuri 57, no. 2 (2017): 107–10. http://dx.doi.org/10.2142/biophys.57.107.

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Li Tiansong, 李天松, 阳荣凯 Yang Rongkai, 高翔 Gao Xiang, and 黄艳虎 Huang Yanhu. "Impulse Response Modeling for Underwater Wireless Laser Transmission." Acta Optica Sinica 39, no. 11 (2019): 1101001. http://dx.doi.org/10.3788/aos201939.1101001.

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Zhigarkov, V. S., and V. I. Yusupov. "Impulse pressure in laser printing with gel microdroplets." Optics & Laser Technology 137 (May 2021): 106806. http://dx.doi.org/10.1016/j.optlastec.2020.106806.

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47

KRUPA, M. M., and A. M. KOROSTIL. "IMPACT OF LASER IRRADIATION ON THE MAGNETO-OPTICAL PROPERTIES OF HYBRID MULTILAYER FILM STRUCTURES." International Journal of Modern Physics B 21, no. 32 (December 30, 2007): 5339–50. http://dx.doi.org/10.1142/s021797920703840x.

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The influence of nanosecond laser impulse irradiation on the magneto-optical properties of multilayer film nanostructures Bi – SiC – TbFe – SiC , SiC – TbFe – SiC , SiC – Tb – Au – Fe – SiC , and phthalocyanine dye–bismuth–phthalocyanine dye was investigated. It was shown that this irradiation causes the injection of spin-polarized electrons from magnetic into nonmagnetic layers of the multilayer films. Nonequilibrium magnetization arising in nonmagnetic layers leads to the change of magneto-optical characteristics. The voltage induced by laser irradiation can also produce a directed drift of Bi ions toward the laser beam action.

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48

Zhang, Kui, Gong Liu Yang, Wei Zhen Zheng, and Ren Dong Ma. "Digital Signal Processing Approach of Dithered RLG Based on IFIR Digital Filter." Advanced Materials Research 989-994 (July 2014): 4195–99. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.4195.

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An interpolated finite impulse response (IFIR) digital filter approach was purposed to improve the demerits of traditional finite impulse response (FIR) digital filter in the case of noise attenuation for dithered Ring Laser Gyroscope (RLG). Concentrated on the time delay and computation complexity, a comparison of FIR and IIR digital filter was illustrated. By optimizing the stretch factor L, an IFIR digital filter was designed to reach the requirements of a typical RLG. The static experiment results show that the impulse number is decreased from 250 to below 0.15, attenuation of the dither noise is nearly 100 dB and group delay remains the same level by 11.25ms.

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Shitarev, I. L., V. G. Smelov, and A. V. Sotov. "Repair of a Gas Turbine Blade Tip by Impulse Laser Build-Up Welding." Applied Mechanics and Materials 682 (October 2014): 96–99. http://dx.doi.org/10.4028/www.scientific.net/amm.682.96.

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This article deals with the repair process of a gas turbine blade tip by impulse laser build-up welding, optimization algorithm for the technological process is proposed and macro-and micrograph of the investigated surface was made.

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50

Ricci, T., and M. Mazzoni. "Experimental investigation of temperature gradients in the inner ear following Argon laser exposure." Journal of Laryngology & Otology 99, no. 4 (April 1985): 359–62. http://dx.doi.org/10.1017/s0022215100096833.

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Abstract In microsurgery of the middle ear using argon laser, heat is produced on the sensorineural structures adjacent to the irradiated bones.Thermal gradients following laser applications have been measured by means of special thermocouples.The footplate was perforated by a 50 msec. ray applied both at 380 m Watt and at 460 m Watt. The maximum temperature increase registered in the labyrinthine spaces was respectively 2oc. and 3.5oC.Coagulation of the promontory mucosa was performed using 100 msec. impulses at 200 m Watt. At the end of a series of 12 applications the temperature increase at the level of the basal coil was 1.4oc.From the above results the authors conclude the no damage is induced during laser microsurgery and that, considering the power and time values relative to impulses, the use of laser in routine clinical practice should be relatively safe.

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