- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Electron acceleration up to MeV level under nonlinear interaction of subterawatt femtosecond laser chirped pulses with Kr clusters
摘要： The acceleration of electrons to MeV energies from a Kr cluster jet irradiated by a relativistic (6 × 1018 W cm?2) femtosecond laser pulse is studied. For the first time, the action of transform-limited laser pulse effects on the generation of hot electrons with an effective temperature (Thot) of around 150 keV is experimentally demonstrated. The particles were accelerated in the plasma channel formed under self-focusing of the laser beam. Introducing a linear positive chirp together with pulse elongation from 50–~120 fs results in substantially enhanced hot electrons flux with a growth of Thot up to 300 keV and a maximal energy of over 2 MeV. The observed effect may be related to the strongly nonlinear propagation of the pulse through plasma, accompanied by more favorable conditions for efficient particles energy gain and pulse nonlinear compression.
关键词： femtosecond laser,nonlinear phenomena,krypton,clusters,laser-driven electron acceleration
更新于2025-09-23 15:21:01
-
Lasing efficiency of krypton ions in the (8a??14)-nm band upon pulsed laser excitation
摘要： The emission spectra of krypton plasma in the range of 8 – 14 nm upon excitation of a pulsed gas jet by 1.06-mm Nd : YAG laser radiation with a pulse energy of 0.85 J, pulse duration of 5.2 ns, and repetition rate of 10 Hz are investigated. The krypton emission spectrum is a wide (8 – 14 nm) band, peaking at 10.3 nm, which is formed by a series of much narrower lines. The observed lines are identified, and the fraction of laser pulse energy converted into the (8 – 14)-nm emission band and emitted into half-space (2p sr) is determined. The maximum conversion efficiency is found to be 21 %. The expected throughputs of lithographic systems with sources based on Sn, Xe, and Kr ions for different wavelengths, correspond- ing to the emission peaks of ions of these materials, are compared.
关键词： extreme UV radiation,lithography,pulsed gas target,conversion efficiency,laser spark,krypton plasma
更新于2025-09-23 15:21:01
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Sub-20 fs ? 10.5 W Visible Pulse Generation from Yb-Doped Fiber Laser
摘要： High-power high-repetition rate femtosecond ytterbium-doped fiber lasers offer new perspectives in femtochemistry, solid-state physics and strong field physics. In particular, high-order harmonic generation (HHG) driven by Yb-fiber laser has demonstrated high photons flux in extreme ultraviolet (XUV) spectral range [1,2]. Shortening the laser pulse improves the achievable time resolution in pump-probe experiments and also the efficiency and the spectral extent of HHG (cutoff wavelength). However, the gain bandwidth of the Yb:fiber limits the pulse duration in the 250 fs - 130 fs range. To solve this issue, nonlinear pulse compression experiments using Yb:fiber lasers have been carried out at the fundamental wavelength (1030 nm) to downscale the pulse duration in the 10 fs range [3,4]. On the other hand, so far the highest reported XUV photons flux up to milliwatt-class has been obtained at 515 nm driving wavelength with 11W - 85 fs pulses [5]. While frequency doubling an ultrashort (< 30 fs) pulse requires a trade-off between efficiency and pulse duration lengthening, we present in this work an efficient and high power sub-20 fs visible laser source based on the second harmonic generation (SHG) of a high energy Yb-doped femtosecond fiber laser followed by a nonlinear compression stage in a krypton-filled capillary.
关键词： femtosecond ytterbium-doped fiber lasers,nonlinear pulse compression,krypton-filled capillary,second harmonic generation,high-order harmonic generation
更新于2025-09-16 10:30:52
-
Etch Performance of KRF Excimer Laser Micromachining Characterization on Silicon Material
摘要： Excimer laser micromachining enables us to overcome the conventional lithography-based microfabrication limitations and simplify the process of creating three dimensional (3D) microstructures.The objective of this study is to investigate the relation between the number of laser pulses, number of laser passes through the channel of ablation site and their etch performance. Parameters such as frequency, fluence and velocity were retained as constants. In this paper, we present a parametric characterization study on silicon using KrF excimer laser micromachining. From the result, the etch rate change were recorded as the two major laser parameters (Number of laser pulses and number of laser passes) were varied. Both parameters were showing declination profile however from comparing both graphs, it showed that etch rate dropped more steeply when varied number of laser passes rather than number of pulses.
关键词： Krypton fluoride,silicon,KrF,excimer laser
更新于2025-09-16 10:30:52
-
Measurement of pressure shift and broadening for Ar and Kr 4s[3/2]2?→?4p[5/2]3 transition in rare gases using diode-laser spectroscopy
摘要： In this work simultaneous measurements of pressure broadening and shift coe?cients for 811.5 nm Ar and 811.3 nm Kr spectral lines of the 4s[3/2] 2 → 4p[5/2] 3 transition were performed. Assessment of gas temperature was done by determining Doppler width components of the lines’ Voigt pro?les. Pressure shift coe?cients for the mixtures Ar:Ne, Kr:Ne and Kr:Ar were determined for the ?rst time. Their values in units of 10 -10, reduced to 300 K are: β Ar:Ne = -0.51 ± 0.05, β Kr:Ne = -0.65 ± 0.01, β Kr:Ar = -2.07 ± 0.08. Additionally we demonstrated the use of easily available starters for ?uorescent lamps as sealed Ar discharge cells for reference optical frequency.
关键词： Spectral line pressure shift,Radio-frequency discharge,Metastable argon and krypton atoms,Optically pumped all-rare-gas laser,Diode-laser absorption spectroscopy
更新于2025-09-11 14:15:04
-
Characteristics of krypton ion emission from a gas field ionization source with a single atom tip
摘要： A scanning ion beam instrument equipped with a gas ?eld ionization source (GFIS) has been commercialized, but only helium and neon are currently available as GFISs. The characteristics of krypton ion emission from a single atom tip (SAT) have not been reported yet. In this study, the characteristics of krypton ion emission were investigated by ?eld ion microscopy. At 65 K, the krypton ion emission current reached approximately 40 pA, which is 1 order of magnitude higher than that at 130 K. As the krypton gas pressure was increased, the krypton ion current increased. At a pressure of 0.3 Pa, the emission current was anticipated to reach 200 pA, which may be high enough for nanofabrication. The variation of the krypton ion current was as low as 5% in one hour. We concluded that a krypton ion beam instrument equipped with a GFIS will be a powerful tool for nanofabrication.
关键词： gas field ionization source,field ion microscopy,nanofabrication,single atom tip,krypton ion emission
更新于2025-09-09 09:28:46
-
Gas mixing effect on Kr ion currents from an ECR ion source
摘要： Pure and different support gas-mixed krypton plasmas are produced using the 14.5 GHz all permanent-magnet based electron cyclotron resonance (ECR) ion source. The ions are extracted and the charge state distributions (CSDs) are studied. The H2, He, N2, O2, Ne, Ar, CH4 and CO2 gases are used as support gases. One of the support gases are mixed with Kr at several mixing ratios and its effect on the outputs currents of the Kr ions are studied. The total effective charge, as well as effective charges of Kr and mixing gas ions are calculated from the measured ion currents. The total ion loss rates are also calculated. The gases N2, O2, Ar and CO2 are found to exhibit better mixing effect in the enhancement of output of highly charged ions. The best enhancement in the output currents of Kr ions is observed in case of O2 as the mixing gas under certain conditions. To the best of our knowledge such a detail comparative study on the influence of mixing gas has not been reported so far for ECR ion-beam application.
关键词： Krypton,Electron cyclotron resonance,Charge state distribution,Gas mixing
更新于2025-09-09 09:28:46