An ultrashort pulse laser is a laser that emits ultrashort pulses of light, generally of the order of femtoseconds to ten picoseconds. Thus they are also known as ultrafast lasers.[1] But "ultrafast laser" is a misnomer, since the speed of light is constant in a given medium.[2]
Common current ultrashort pulse laser technologies include Ti-sapphire lasers and dye lasers. High output peak power usually requires chirped pulse amplification of a seed pulse from a modelocked laser. Dealing with high optical powers also needs the nonlinear optical phenomena to be taken in account.