Fig. 1. Multi-focus laser processing for efficient fabrication of a trapezoid groove. (a) Schematic of multi-focus laser processing. (b) Simulated light intensity field of multi-focus spot. (c) 45° tilted view of multi-focus ablation. (d) 45° tilted view of multi-focus ablation after chemical etching. (e) Cross-sectional view of the groove on fused silica after laser processing, observed with an optical microscope. (f) Three-dimensional view of the groove after chemical etching, captured by laser scanning confocal microscopy. (g) 45° tilted view of the groove, imaged with scanning electronic microscope. Scale bars: 100 μm.

Fig. 2. Correction of multi-focus modulation. (a) Illustration of single-spot coordinate. (b) Illustration of V-shaped design (left) and experimental results on fused silica produced by 20× objective without (middle) and with (right) refractive index correction. (c) Illustration of designed grid (left) with corresponding experimental results on fused silica produced by 50× objective without (middle) and with (right) complex correction. Scale bars: 100 μm.

Fig. 3. Uniformity improving of multi focus by randomization of their coordinates in fused silica. Illustration, phase diagram, fast Fourier transform images of phase diagrams showing circular Moiré patterns, light intensity field simulation, and bulk ablation of V-shape dot array with uniform multi foci of (a) 13 points , (b) 21 points , and (c) 21 points with randomized position. Scale bars: 100 μm.

Fig. 4. Point-by-point energy adjustment of dot array with high aspect ratio. (a) Illustration of selection of energy adjustment coefficient. Light intensity field simulation and experimental results on fused silica of 15-point array ablation or 33-point array without (b,d,f) and with energy adjustment (c,e,g). Scale bar: 100 μm.

Fig. 5. The profile and surface roughness of the V-shaped groove. (a) A V-shaped modified region processed by a multi-focus beam with 46 foci. (b) Etching result of V-shaped groove. (c) Designed profile and real profile of V-shaped groove. (d) Surface roughness of V-shaped grooves vary with the number of foci. Scale bars: 100 μm.

Fig. 6. Diverse sectional profiles of glass grooves achieved through spatial multi-focus laser processing combined with chemical etching, along with their various applications. (a) Symmetric and asymmetric V-shaped grooves on fused silica. (b) Arc-shaped grooves on fused silica. (c) Cylinder arrays formed by continuous grooves on fused silica. (d) Trapezoid grooves on borosilicate glass used for optical fiber packaging. Scale bars: 100 μm.