A new generation of ultrafast lasers
Ultrafast lasers, which deliver an energy pulse that lasts only a few femtoseconds, are an important part of many industrial processes. They are employed in fields as diverse as vision correction, solar cell manufacturing or semiconductor metrology. In scientific laboratories and industry, one can find two types of lasers capable of delivering short pulses. Sapphire lasers can deliver very short pulses at moderate repetition rates and power. However, ytterbium lasers combine very high repetition rates and power, but produce pulses that are not so short. Within the FLAME (Femtosecond light amplifiers in the megahertz regime) project, four European companies and two research institutions joined forces to produce an innovative ultrafast laser source combining the best of both worlds. Project members developed a light source that can produce very short and energetic pulses at a rate of two million pulses per second. Moreover, the wavelength can be varied across the whole visible spectrum and the near-infrared. Project developments helped realise an ultrafast laser with two orders of magnitude higher repetition rate, an order of magnitude shorter pulse duration and higher average powers than commercially available laser amplifiers, existing fiber lasers or few-cycle oscillators. Using a non-linear optical process known as optical parametric amplification, researchers were able to transfer energy from one laser pulse to another, thereby obtaining ultrashort pulses with high energy at very fast rates. FLAME members did not only engage in the development of ultrafast laser sources but also complemented their activities with the development of dedicated new detection instrumentation. In particular, they developed sophisticated electron and ion imaging detectors tailored to the experimental research carried out with the novel laser systems. FLAME's light source represents a new generation of femtosecond lasers with high-pulse energy and megahertz repetition rates that should allow the ultrafast laser market to grow with new players.
Keywords
Ultrafast lasers, repetition rates, short pulses, ion imaging, megahertz
