Terawatt lasers

An alternative way to preform a channeled plasma consists in exploiting the nanosecond precursor that usually precedes a short femtosecond pulse in the output of a multi-terawatt laser system. In fact, the amplified spontaneous emission (ASE) pedestal has typically an intensity 106-1010 times lower than the main pulse, which, however, can be sufficient to ionize a gas-jet or a solid target. This drawback can be turned into a benefit assuming that this long precursor can prepare the plasma channel for the short pulse propagation. 

Yoshida M, Fujimoto Y, Hironaka Y, Nakamura KG, Kondo K, Ohtani M, Tsunemi H (1998) Generation of picosecond hard x rays by terawatt laser focusing on a copper target. Appl. Phys. Lett. 73 2393-2395... 

Guo T, Spielmann Ch, Walker BC, Barty CPJ (2001) Generation of hard X-rays by ultrafast terawatt lasers. Rev. Sci. Instrum. 72 41-47... 

Fig. 14.1. White-light filament generated in the atmosphere by infrared femtosecond-terawatt laser pulses. (Photo C. Wedekind)...

H. Wille, M. Rodriguez, J. Kasparian, D. Mondelain, J. Yu, A. Mysyrow-icz, R. Sauerbrey, J. P. Wolf, L. Woeste, TeramobUe a mobile femtosecond-terawatt laser and detection system, European Physical J. Appbed Physics 20, 183 (2002)... 

P. Maine, D. Strickland, P. Bado, M. Pessot, G. Mourou, Tabletop terawatt laser by chirped pulse amplification, IEEE Journal of Quantum Electronics 24, 398 (1988)... 

In summary, from the direct observation of the vertical propagation of femtosecond-terawatt laser pulses in the atmosphere, it is demonstrated that not only the filaments, but also the whole beam, have a non-linear behaviour [18]. The overall beam is partially recollimated near to the non-linear focus. Also, filamentation can occur at 2 km altitude, which is essential for remote atmospheric applications of filamentation. 

Oulianov DA, Crowell RA, Gosztola DJ, Shkrob lA, Korovyanko OJ, Rey-de-Castro RC. (2007) Ultrafast pulse radiolysis using a terawatt laser wake-field accelerator. /Ap P/tyr 101 053102-053102-9. 

Saleh N, Flippo K, Nemoto K, Umstadter D, Crowell BA, Jonah CD, Trifimac AD. (2000) Pulse radiolysis of liquid water using picosecond electron pulses produced by a table-top terawatt laser system. Rev Sci Instrum 71 2305-2308. 

Fig. 10. Longitudinally and transversely recorded spectra from a N2 jet, subjected to focused terawatt laser radiation (From Refs [40,43]).

Much insight in the dissociation patterns of molecules can be obtained by using the so called covariance mapping technique [48], Terawatt laser excitation allowed such experiments for CO2 to be performed in a non-explored power density regime [49]. 

Fig. 6.57 Spectral intensity distribution of the higher harmonics produced by focussing a femtosecond terawatt laser at X = 720 nm into a neon jet [749]...

Fig. 10.23 Spectral continuum emitted by the plasma spots along the propagation path of terawatt laser pulses in the atmosphere [1472]...

An example of X-ray amplification in nickel-like palladium Pd " is shown in Fig. 5.110, where a terawatt laser pulse created a hot plasma from a palladium surface. By recombining electrons with highly charged palladium ions, inversion between two Rydberg states of Pd + could be achieved, resulting in an intense laser line at A = 14.7 nm [508, 509]. 

Fig, 8.55. Schematics of a high-repetition-rate terawatt laser system based on chirped pulse amplification [8.161, 8.124)... 

Our main purpose is to compare absorption and luminescence spectra of R(IH) in glasses with the behavior in crystalline compounds and in aqueous solution. In one way, it is surprising how close many of the similarities are, and also how technologically attractive glasses can be as laser materials compared to crystals. It may be noted that the largest-scale terawatt lasers, such as the SHIVA and NOVA systems in Livermore, CA, are neodymium(III) glasses. We summarize most of the major results described in this chapter in seven conclusions ... 

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