Di, 19.03.2019  |  11:00 Uhr
seminar room A, R 2.01

Laser produced plasmas for high-order harmonic generation

Kavya Hemantha Rao | Griffith University, Brisbane, Australia

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Laser produced plasmas (LPP) are interesting due to its variety of applications including high
harmonic generation, attosecond pulse generation, nanoparticle and nano-cluster generation,
pulsed laser deposition etc. Controlling the morphology and plume parameters are inevitable
before using LPP’s for its different applications. Here, investigations on controlling the
morphology and characteristics of a picosecond laser produced chromium plasma will be discussed.
To do so, single-pulse (SP) and double-pulse (DP) irradiation schemes are employed in
which the total energy in the SP scheme is divided into two and irradiates the target back to back
with a controllable delay between the two pulses for the DP scheme. The expansion properties for
different DP schemes are compared with its SP counter part for various ambient pressures, interpulse
delays and irradiation energies. The experiment is performed using an uncompressed » 60
ps with a maximum energy of 550 ¹J at a repetition of 1 kHz and the morphology of the plume is
understood via fast imaging with a temporal resolution of » 2 ns. These experiments infer that
the plasmas produced by DP can be used suitably to mimic the expansion features of a SP plasma
at 101 Torr. To be precise, the expansion features of SP at higher pressures can be recreated in DP
scheme at lower pressures » 10¡6 Torr for the first time. Such a spatio-temporally optimized plasmas
would further be employed in high-order harmonic generation (HHG) experiments aiming at
a larger energy cut-off.