The dependence of the normalized signal strength in water on (top left) different pulse energies and pulse lengths, (top right) different peak powers and pulse lengths, (bottom left) different pulse energies and repetition rates and (bottom right) different average powers and repetition rates. For the top row the repetition rate was set to 1 kHz and in the bottom row the pulse length was kept constant at 10 ps for all measurements. Arbitrary unit (a.u.).