Extremal black holes from colliding gravity-catalyzed electromagnetic waves

In the Einstein–Maxwell theory, black hole solutions can arise from collisions of gravity-coupled electromagnetic waves. In the limit of vanishing gravitational waves, we show that an extremal Reissner–Nordström black hole can form as a result of such an isometry. We also show that direct collision of pure electromagnetic waves without the catalyzing role of gravity creates the near-horizon geometry of the same black hole, supporting this mechanism. Due to the quantum restrictions, such black holes can have horizon radii in the range [Formula: see text] and [Formula: see text]. If such black holes from pure light, either by collision or collapse, do exist, they challenge conventional expectations, and this may open a new frontier in our understanding of black holes. The generation of impulsive gravitational waves in the process of colliding light beams may be instrumental in the detection of such black holes.