The picosecond pulsed sources are either laser diode based or LED based devices that can be operated at variable, user-adjustable repetition rates up to 80 MHz. They cover discrete wavelengths from 255 nm to 1990 nm or are tunable in the VIS. Power levels vary between µW and hundreds of mW for the most powerful, fibre amplified versions. Pulse widths can be as short as 40 ps. The following table gives a rough overview about the key parameters. It should be noted that all mentioned parameters do strongly depend on the individual wavelength.