E. V. Rakov

Generation of superintense femtosecond pulses by the Cr:forsterite laser system

A repetitively pulsed chromium-forsterite laser system is created. High-power femtosecond light pulses are generated at the fundamental (1.24 µm) and second-harmonic (0.62 µm) wavelengths. Theoretical analysis is performed to optimize the output pulse energy. Laser pulses with a duration of 110 fs, an energy of 1 mJ, and a repetition rate of 1–50 Hz are generated. The intensity of the focused beam is greater than 1016 W/cm2. High-efficiency radiation conversion into the second harmonic is used to increase the energy contrast of the generated pulses.

Hot plasma diagnostics during femtosecond laser ablation in a cavity

On-line diagnostics of hot plasma induced by superintense femtosecond laser pulses in a cavity during the deep hole drilling of solid target has been developed. Such a plasma is characterized by higher values of hard X-ray yield and hot electron temperature in comparison with the same parameters measured for flat nearsurface plasma. Dynamics of X-rays yield in the cavity during the deep hole drilling demonstrates several repetitive stages. The yield and energy of X-rays from plasma ignited in a cavity depend on the beam waist position respect to the target surface plane, i.e. focusing regime. We have detected strong second harmonic signal that correlated with hard X-Ray yield in the time of cavity formation. Depth resolved elemental analysis of compound targets, based on this diagnostics technique, has been proposed.

Simple design of femtosecond laser plasma highly stable hard x-ray source using free surface of liquid gallium

It was shown that liquid gallium heated up to 270°C can be used as a target for 10 Hz femtosecond laser plasma highly stable x-ray source. The decreasing of hard x-ray yield during 50000 laser shots is less then 25% and can be easy compensated by additional focusing of objective or temperature tuning.