Picosecond optical radiation systems and methods of use

A method for treating pigment particles, the method comprising:

• providing a picosecond pulse radiation source comprising a mode locked laser, wherein the mode locked laser is a multi transverse mode laser comprising,
• a solid state crystal medium;
• a resonator defined by a first mirror and a second mirror at opposite ends of a resonator optical axis, the solid state crystal medium disposed therein;
• a fundamental frequency which is the speed of light divided by a round trip optical path length (2 L) of the resonator;
• a mode locking element that is modulated at a frequency that is a sub-harmonic (l/n) of the fundamental frequency, which is the speed of light divided by round trip optical path length (2L) where n is a whole number greater than 1;
• generating a pulse of optical radiation, using the pulse radiation source, wherein the pulse has a duration of less than 1000 picoseconds;
• and
• directing the pulse to one or more pigment particle target to disrupt the one or more pigment particle target and promote clearance thereof.