Transient plasma mirror/filter manipulates high-energy laser pulses

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).