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Oscillator of LUCA facility

The femtosecond laser facilities of the DRECAM offer to the national and european researchers, ultra short pulse duration and high intensity laser lines instrumented by numerous diagnostics. These laser beams allow studies on high intensity laser matter interactions as well as two colours experiments. This laser platform provides power peaks until 10TW, intensities of 1019W/cm2 and pulse durations about 35fs. What makes the originality of these facilities is the number of experimental lines available (4) and the tunability (from IR to XUV) which allow simultaneous pump-probe experiments with two photons. This is supplemented by an important scientific and technical support team.  
#415 - Last update : 03/25 2005
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The absorption of UV light by DNA may cause carcinogenic changes. This occurs because chemical reactions, susceptible to deteriorate the genetic code, are triggered by the excess energy deposited by the UV absorption. Up to now, it was not known how this excess energy was distributed among the bases of the DNA. It was only postulated that each base absorbs a photon individually. By using ultrafast laser pulses, we have now shown that this assumption is not valid (J. Amer. Chem. Soc.
Our recent experimental and theoretical investigations dealing with model DNA double helices, composed of either adenine-thymine (A-T) or guanine-cytosine (G-C) base pairs and guanine quadruplexes shed some light on the excited states populated by photon absorption and their relaxation, energy transfer among bases and one-photon ionization.


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