Doctorant: Limin Meng Directrice: Annie Klisnick Etude expérimentale et simulation numérique des lasers XUV transitoires en mode ASE et injecté Experimental study and numerical simulations of transient XUV lasers in ASE and seeded mode

1 What is XUV laser? XUV (Extreme ultraviolet) laser is the coherent radiation whose wavelength is in the X-ray range(3nm-50nm). XUV

y x z Target(Ti, Mo, Ag….) Pre-Laser Plasma Pump laser HOH 2 production of transient XUV laser 1 ） ionization- pre pulse irradiate in normal direction, 2 ） Pump- interval hundreds ps, grazing incidence pumping (GRIP) 3a ） production of ASE XUV laser- Amplitude Spontaneous Emission (ASE mode) 3b ） production of seeded XUV laser- high order harmonics (HOH) seed ASE XRL Seeded XUV

3 My topic---measure the temporal coherence and the spectral line width of the XUV laser In many application, we need short pulse duration. Such as production of plasma, and the detection of fast process. The duration of current XUV lasers is limited to ~1ps, due to a very narrow bandwidth ( Δλ/λ ∼ ) Our goal is to find strategies to enlarge the bandwidth and reach duration of a few 100 fs

4 How to measure the bandwith of the XUV laser —the variable path difference interferometer Interferometer—view outside L c is the coherent length that we can calculate directly from the experiment results. Interference field Interferometer— principle shown  mobile dihedron fixed tilted dihedron XUV Laser Beam Z CCD

4 the work I have done 1 -- Measurement of the Temporal Coherence of a Seeded GRIP Transient Mo XUV Laser Far field footprint Detected fringes Experiment performed at CSU (USA) Results are submitted to Optics Letters Main conclusion: the coherence length is about 400um, corresponding to a linewidth of about 3mÅ ; spectral narrowing when the length of the plasma amplifier is increased.—agreement with simulation

the work I have done 2 –- Measurement of the Temporal Coherence and the duration of a ASE Transient Mo XUV Laser In the second year, I have done a new experiment, which is performed at LASERIX! We are now analysing the data. Some example of the images and the preliminary results are shown below 0.75 ps 8 ps 4 ps 1.5 ps

5 What I Will do The goal is to define the effect of several parameters to the linewidth: atomic number the electron density ----Preparing new experiment at Laserix ----compare the results with numerical simulation

Thank you for your attention!