Absorption of femtosecond laser pulses in interaction with solid targets

The effects of plasma density scale length on the absorption mechanism of the femtosecond laser pulses interacting with solid targets were studied. The vacuum heating was the main absorption in the plasma in the interaction of fs laser pulses with solid targets when no prepulses were applied. A bitemperature distribution was exhibited by the the energy spectrum of hot electrons ejected out of or injected in to. The absorption of femtosecond laser energy through different mechanisms was depicted by the PIC simulations with an appropriate density scale length.