Characteristics of target interaction with high power UV laser radiation

Thermal conduction, mass ablation rate, pressure and preheat were investigated in the interaction of a frequency tripled Nd: glass laser of power 0.-0.2 TW with flat targets. In the range 10 ¹³-10 ¹⁵{W}/{cm ²} for 400 ps pulses we find: (a) thermal conduction may be described by a flux limiter f = 0.04 ± 0.01; (b) the mass abaltion rate depends on the incident laser irradiance as m̂ = 4.4 × 10 ⁵ (I/10 ¹⁴) ^0.53 g cm ^-2 s ^-1; (c) the pressure near the ablation surface increases approximately linearly with irradiance and is about 70 Mbar at 10 ¹⁵ W/cm ², and (d) preheat as evidenced by K _α X-ray line emission is significantly lower than in λ = 1.05 μm irradiation.