STRONG LASER FIELD INTERACTION WITH DIATOMIC MOLECULES: FROM THE ULTRA-SHORT TO LONG-PULSE REGIME

In the present paper, we compare novel MEDI results on iodine obtained with 30 ps laser pulses to those obtained in the femtosecond regime. The results indicate laser-induced trapping of the molecules not only in the ultra-short pulse regime, but also for the long pulses, since the fragment kinetic energy releases are essentially the same, although the pulse duration is varied over more than two orders of magnitude. Most interestingly, with 30 ps pulses significant post-dissociation ionization of the In+-fragments observed for the first time, proving that near-Coulomb energies and post-dissociation ionization can be observed simultaneously. A femtosecond double-pulse experiment confirms our recent hypothesis of molecular stabilization governing the MEDI interaction.

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Progress in Data Transmission and Storage for Long Pulse Data Acquisition System

Journal of Physics Conference Series ◽

10.1088/1742-6596/2113/1/012065 ◽

2021 ◽

Vol 2113 (1) ◽

pp. 012065

Author(s):

Yu Gu ◽

Mengqi Fan ◽

Chuanqian Tang ◽

Guojing Zhang ◽

Xiaodan Zhang

Keyword(s):

Control System ◽

Data Acquisition ◽

Data Transmission ◽

High Speed ◽

Short Pulse ◽

Test System ◽

Data Types ◽

Pulse Experiment ◽

Long Pulse ◽

And Storage

Abstract Since the study in the field of fusion has gradually developed toward the long-pulse experiment mode, long-pulse data has gradually become one of the main data types for pulsed experiments in the field of fusion. For long-pulse data, which is a kind of pulse-type data, it will be more difficult to transmit and store than short-pulse data because of its significant characteristics. In addition, in the design of data acquisition and control system (DACS) in fusion field, Experimental Physics and Industrial Control System (EPICS) has now gradually become the main framework of experimental control system to meet the diversity of devices and complexity of subsystems in large experimental system. However, due to the limitation of EPICS, its effectiveness in handling data transmission and storage under high speed data acquisition is not satisfactory. To solve the data transmission and storage under high-speed sampling, this paper proposes a data transmission and storage solution based on TCP/IP protocol and MDSplus database, which is designed with the concept of segmentation, i.e., data generated from experiments longer than 100 seconds are uploaded and stored in a segmented form. Currently, this system has been tested and applied, and the test result shows that the solution is feasible and the overall test system operates stably and reliably.

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Petawatt Femtosecond Laser Pulses from Titanium-Doped Sapphire Crystal

Crystals ◽

10.3390/cryst10090783 ◽

2020 ◽

Vol 10 (9) ◽

pp. 783

Author(s):

Hiromitsu Kiriyama ◽

Alexander S. Pirozhkov ◽

Mamiko Nishiuchi ◽

Yuji Fukuda ◽

Akito Sagisaka ◽

...

Keyword(s):

High Intensity ◽

Short Pulse ◽

Beam Quality ◽

Laser Pulses ◽

High Energy ◽

Femtosecond Laser Pulses ◽

Small Scale ◽

Sapphire Crystal ◽

Chirped Pulse Amplification ◽

Ultra Short Pulse

Ultra-high intensity femtosecond lasers have now become excellent scientific tools for the study of extreme material states in small-scale laboratory settings. The invention of chirped-pulse amplification (CPA) combined with titanium-doped sapphire (Ti:sapphire) crystals have enabled realization of such lasers. The pursuit of ultra-high intensity science and applications is driving worldwide development of new capabilities. A petawatt (PW = 1015 W), femtosecond (fs = 10−15 s), repetitive (0.1 Hz), high beam quality J-KAREN-P (Japan Kansai Advanced Relativistic ENgineering Petawatt) Ti:sapphire CPA laser has been recently constructed and used for accelerating charged particles (ions and electrons) and generating coherent and incoherent ultra-short-pulse, high-energy photon (X-ray) radiation. Ultra-high intensities of 1022 W/cm2 with high temporal contrast of 10−12 and a minimal number of pre-pulses on target has been demonstrated with the J-KAREN-P laser. Here, worldwide ultra-high intensity laser development is summarized, the output performance and spatiotemporal quality improvement of the J-KAREN-P laser are described, and some experimental results are briefly introduced.

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Theoretical and experimental analysis of scan angle-depending pulse front tilt in optical systems for laser scanners

Advanced Optical Technologies ◽

10.1515/aot-2015-0046 ◽

2016 ◽

Vol 5 (1) ◽

Author(s):

Lasse Büsing ◽

Tobias Bonhoff ◽

Lars Behnke ◽

Jochen Stollenwerk ◽

Peter Loosen

Keyword(s):

Experimental Analysis ◽

Short Pulse ◽

Laser Pulses ◽

Industrial Applications ◽

Optical Systems ◽

Full Potential ◽

Pulse Front ◽

Laser Scanners ◽

Short Laser Pulses ◽

Ultra Short Pulse

AbstractFor realising fast and highly dynamical laser-based material processing, scanner systems are already utilised for many different industrial applications. Furthermore, ultra-short pulsed (<1 ps) laser sources provide possibilities of processing most different materials with highest accuracy. Owing to the large spectral bandwidth of ultra-short laser pulses, dispersion in optical components becomes relevant. The dispersion in optical systems for laser scanners may lead to scan angle-depending pulse properties as, for example, pulse front tilt. The investigation of these effects is not state of the art today but absolutely necessary to exploit the full potential of laser scanners for ultra-short pulse applications. By means of an exemplary focusing lens, the simulation and experimental analysis of scan angle-depending pulse front tilt is presented for the first time.

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Ablation of Subsurface Tumors Using 1552 nm Ultra-Short Pulse Laser

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192415 ◽

2008 ◽

Author(s):

Shreya Raje ◽

Amir Sajjadi ◽

Kunal Mitra ◽

Michael S. Grace

Keyword(s):

Laser Beam ◽

Pulse Laser ◽

Continuous Wave ◽

Short Pulse ◽

Laser Source ◽

Short Pulse Laser ◽

Fiber Optic Probes ◽

Laser Immunotherapy ◽

Ultra Short Pulse ◽

Long Pulse

Over last two decades lasers have been used for the treatment of subsurface tumors. Various techniques such as Laser-induced Hyperthermia, Laser Interstitial Thermal Therapy (LITT), and Laser Immunotherapy have been developed for the successful ablation of subsurface tumors by different researchers. All these techniques use photo-thermal mechanism for tumor ablation by delivering thermal energy at the tumor site. In all these existing techniques, either continuous wave (CW) or long pulse laser source has been used, which often produces larger heat affected zone as compared to that produced by short pulse laser. Moreover, the delivery of laser beam at the target site is achieved through fiber optic probes which often require perforation of the skin. These drawbacks can be eliminated if a converging laser beam from a short pulse laser source is directly focused at the subsurface location to ablate the tumor.

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Time of flight measurements of ion energies produced by 140 fS laser pulses at the Lawrence Livermore National Laboratory ultra short-pulse laser

10.1063/1.46876 ◽

1994 ◽

Cited By ~ 1

Author(s):

G. Guethlein ◽

D. Price ◽

J. Swenson ◽

M. Glinsky ◽

R. Shepherd ◽

...

Keyword(s):

Short Pulse ◽

Lawrence Livermore National Laboratory ◽

National Laboratory ◽

Laser Pulses ◽

Short Pulse Laser ◽

Ion Energies ◽

Fs Laser ◽

Ultra Short Pulse ◽

Flight Measurements ◽

Ultra Short Pulse Laser

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Measurement of ultrashort laser ablation of four metals (Al, Cu, Ni, W) in the single-pulse regime

Advanced Optical Technologies ◽

10.1515/aot-2019-0064 ◽

2020 ◽

Vol 9 (3) ◽

pp. 131-143

Author(s):

Thibault Genieys ◽

Marc Sentis ◽

Olivier Utéza

Keyword(s):

Pulse Duration ◽

Ablation Threshold ◽

Short Pulse ◽

Scaling Law ◽

Single Pulse ◽

Laser Pulses ◽

Ablation Rate ◽

Single Shot ◽

Pulse Regime ◽

Short Pulse Duration

AbstractWe provide measurements of the ablation of four post-transition and transition metals [aluminum (Al), copper (Cu), nickel (Ni) and tungsten (W)] irradiated by single 800 nm laser pulses, in ultrashort regime from 100 femtosecond (fs) pulse duration down to 15 fs covering a temporal range little explored as yet. For each metal and pulse duration tested, we measured its ablation characteristics (depth and diameter) as a function of incident energy allowing us to determine its laser-induced ablation threshold and ablation rate in a single-shot regime. For all the metals studied, we observed a constant ablation threshold fluence as a function of pulse duration extending this scaling law to pulse duration of few-optical-cycles. We provide evidence of the interest of adjusting the incident fluence to maximize the energy specific ablation depth but also of the absence of any peculiar advantage related to the use of extremely short-pulse duration for ablation purposes. Those informative and detailed ablation data have been obtained in the single-pulse regime and in air ambiance. They can serve as rewarding feedback for further establishing smart strategy for femtosecond laser micromachining and laser damage handling of metallic and metal-based components as well as for enhancing accuracy of modeling of fs laser interaction with metals in ultrashort regime.

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Spatial extension of the electromagnetic field from tightly focused ultra-short laser pulses

Laser and Particle Beams ◽

10.1017/s0263034613000906 ◽

2014 ◽

Vol 32 (1) ◽

pp. 89-97 ◽

Cited By ~ 6

Author(s):

L. Ionel ◽

D. Ursescu

Keyword(s):

Short Pulse ◽

Laser Pulses ◽

Measurement Point ◽

Speed Of Light ◽

Short Pulses ◽

Spatial Extension ◽

Rayleigh Range ◽

Short Laser Pulses ◽

The One ◽

Ultra Short Pulse

AbstractIt is shown that in the focus of ultra-short pulses of duration t, the equivalent relation s = ct, where c is the speed of light and s the spatial extent of the pulse of the collimated pulse, does not hold. While the duration of one pulse is constant and independent of the measurement point, the spatial extension of the ultra-short pulse can be spatially shorter a factor more than 10 compared to the one obtained from the usual relation. The result is explained in correspondence with the extension of the Rayleigh range. Few femtosecond long gamma bursts can thus be generated in Thomson backscattering experiments performed in the lambda cube regime.

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ANALYSIS OF ULTRAHSORT LASER PULSES PROPAGATION IN MEDIUM: LITHARGE GLASS SF56A

International Journal of Research -GRANTHAALAYAH ◽

10.29121/granthaalayah.v7.i2.2019.994 ◽

2019 ◽

Vol 7 (2) ◽

pp. 58-67

Author(s):

Khelladi Mounir

Keyword(s):

Pulse Propagation ◽

Short Pulse ◽

Propagation Distance ◽

Laser Pulses ◽

Dispersive Media ◽

Complete Analysis ◽

Closed Form Solutions ◽

Time Frequency ◽

Simulation Techniques ◽

Ultra Short Pulse

Propagation of an ultra-short lasers pulses in a linear optical medium consisting of free space, dispersive media. However, analytical methods have the limitations of not being able to handle arbitrary pulse profiles. Also, closed form solutions are often obtained after certain levels of approximations. This has motive a few studies based on the use of numerical simulation techniques in the analysis of pulse propagation. In view of the recent advance in ultra-short pulse propagation, a strong need is felt for developing a numerical formalism capable of performing such a complete analysis of the issues involved in pulse propagation. This allows us to analyze the pulse in the time-frequency domain at any arbitrary plane. With this tool, we investigate the spectral and temporal evolution of ultra-short pulses at any arbitrary propagation distance.

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TEMPORAL SOLITON: GENERATION AND APPLICATIONS IN OPTICAL COMMUNICATIONS

Jurnal Teknologi ◽

10.11113/jt.v78.7532 ◽

2016 ◽

Vol 78 (3) ◽

Cited By ~ 1

Author(s):

IS Amiri ◽

SE Alavi ◽

ASM Supa'at ◽

J. Ali ◽

H Ahmad

Keyword(s):

Short Pulse ◽

Chromatic Dispersion ◽

Laser Pulses ◽

Optical Soliton ◽

Short Pulses ◽

Soliton Pulse ◽

Chaotic Signals ◽

Nonlinear Condition ◽

Ultra Short Pulse ◽

Soliton Generation

In general, the temporal and spectral shape of a short optical soliton pulse does not change during propagation in a nonlinear medium due to the Kerr effect which balances the chromatic dispersion. Microring resonators (MRRs) can be used to generate chaotic signals. The smaller MRR is used to form the stopping and filtering system. The employed optical material was InGaAsP/InP, which is suitable for use in the practical devices and systems. The tuning and manipulation of the bandwidth of the soliton signals is recommended to control the output signals. The MRRs can be applied to produce ultra-short pulses, where the medium has a nonlinear condition, thus, using of soliton laser becomes an interesting subject. Therefore, an ultra-short pulse in the scope of pico and femtoseconds soliton pulses can be utilized for many applications in engineering communications. In order to obtain smaller bandwidth of the optical soliton pulses, we propose integrating series of MRRs. In this study, 5 fs soliton pulse could be generated using a series of five MRRs. The soliton signals experience less loss during the propagation, where they are more stable compared to normal conventional laser pulses. Using the series of MRRs connected to an add/drop system, shorter soliton bandwidth and highly multi soliton pulses can be obtained. Therefore, generation of ultra-short multi picosecond (1.2 and 1.3 ps), could be performed, where the radius of the add/drop system has been selected to 50 and 300 µm respectively.

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