Fig. 3: The ion distribution with different pump beam sizes and shapes and the chemical composition analysis of the ring structure.

a PL emission mapping at a detection wavelength of 670 and 790 nm after local illumination for 1 h at beam size of ~1.2 μm/8 suns, ~130 μm/1 sun, and ~1 mm/1 sun, respectively. b PL mapping after local illumination with a beam size of ~1 mm over an annular aperture with a 1 mm diameter pinhole and a center obstruction target of 850 μm. c Absorption spectra of the film at the brightest position of the ring and the center of the illuminated region with a reference included. Inset shows PL mapping at 670 nm after local light illumination by ~12 μm beam for 1 h