In a peer reviewed article published in Optics Express, graduate student researcher Kyle Chesnut and Professor Chris Barty presented a novel way of achieving exawatt-scale (1E18 Watts) laser pulses, i.e. pulses with up to 2 orders of magnitude higher peak power than generally available today.
High peak power laser pulses are typically created via chirped pulse amplification (CPA), where a low-energy, short-duration pulse is dispersed, or “stretched,” in time. The resulting long duration, chirped pulse enables efficient energy extraction from solid state laser amplifiers without damage. After amplification the “chirp” on the pulse is removed with a parallel grating pair compressor and in doing so produces a high-energy, short-duration, high-peak-power pulse. CPA has been used to create petawatt-class (1E15 Watts) pulses at many labs around the globe. Professors Gerard Mourou and Donna Strickland were recipients of the 2018 Nobel Prize in Physics for developing CPA. It is possible to amplify a pulse to even higher energies than is allowed with chirped pulse amplification if the pulse is chirped in both space and time (both transverse and parallel to the direction of the beam’s propagation) (US680405B2). In their paper titled “Ideal spatio-temporal pulse distribution for exawatt-scale lasers based on simultaneous chirped beam and chirped pulse amplification,” Kyle and Chris presented the ideal 20 ns, spatio-temporally chirped pulse that would enable amplification to 25 kJ in a 40cmx40cm, Nd:Mixed-glass laser system. They further showed that this pulse could be compressed to ~100 fs using a novel six grating compressor arrangement, and in doing so could yield a laser pulse with a record breaking peak power of >0.2 exawatts!