The scientific community invests tremendous effort in developing optical components such as lenses, mirrors, gratings, coatings, optical fibers, and even specialized photonic crystals that can withstand and manipulate high-energy laser pulses. But researchers at Heinrich-Heine-Universität Düsseldorf (Germany) have now used counterpropagating laser pulses to generate transient plasma structures that can act as photonic-crystal cavities to manipulate high-energy laser pulses in ways that no solid optical materials can.
Rather than constructing a conventional photonic crystal through layers of dielectrics or metals, the researchers used oppositely propagating laser beams to generate a transient plasma photonic crystal (TPPC) by creating arrays of periodic microplasmas. This density grating has a specific bandgap as dictated by Maxwell-Vlasov simulations that affects the mode profile of laser light entering the TPPC just as if the laser were entering a physical mirror or filter structure. Unlike typical silica optical components that have laser-damage thresholds on the order of 10 J/cm2 for femtosecond to picosecond pulse durations, the TPPC structures can handle fluence values more than five orders of magnitude larger. Reference: G. Lehmann and K. H. Spatschek, Phys. Rev. Lett., 116, 22, 225002 (Jun. 3, 2016).
