Colloidal Silver Nanoparticles-Assisted High-Precision Parallel Laser Writing on Glass and Optical Crystals

Transparent materials, such as glass and optical crystals, are essential components in modern optical systems owing to their superior characteristics in light transmission, mechanical strength, and thermal stability. While femtosecond laser direct writing is a widely used processing method, the high hardness and brittleness of these materials make high-quality processing challenging. A parallel ultrafast laser direct writing method is presented via temporal focusing and the assistance of colloidal silver nanoparticles, which enables the efficient generation of high-quality debris-free nanostructures on borosilicate glass surfaces. These results demonstrate that near-field enhancement from the silver nanoparticles allows for precise material removal at substantially reduced fluences (30% of those in water), while generated bubbles in the liquid efficiently remove debris. To demonstrate the flexibility and scalability of the method, different micro- and nanoscale structures are fabricated on glass surfaces, including 1D and 2D optical gratings with different periods and a centimeter-sized grating logo. Lastly, the generality of the method on silica glass and sapphire crystal substrates is verified to show comparable resolution. This method may find important engineering applications as it provides a high-throughput, high-resolution solution for creating functional surfaces or devices (such as gratings, metasurfaces, and microfluidic channels) on different transparent materials.