Deep-Subwavelength 2D Periodic Surface Nanostructures on Diamond by Double-Pulse Femtosecond Laser Irradiation

Two-dimensional laser-induced periodic surface structures with a deep-subwavelength periodicity (80 nm approximate to lambda/10) are obtained for the first time on diamond surfaces. The distinctive surface nanotexturing is achieved by employing a single step technique that relies on irradiation with two temporally delayed and cross-polarized femtosecond-laser pulses (100 fs duration, 800 nm wavelength, 1 kHz repetition rate) generated with a Michelson-like interferometer configuration, followed by chemical etching of surface debris. In this Letter, we demonstrate that, if the delay between two consecutive pulses is <= 2 ps, the 2D periodicity of nanostructures can be tuned by controlling the number of pulses irradiating the surface. Under scanning mode, the method is effective in treating uniformly large areas of diamond, so to induce remarkable antireflection properties able to enhance the absorptance in the visible up to 50 times and to pave the route toward the creation of metasurfaces for future diamond-based optoelectronic devices.

Automated summary

This study demonstrates, for the first time, the achievement of two-dimensional laser-induced periodic surface structures with deep-subwavelength periodicity on diamond surfaces. The method involves using two temporally delayed and cross-polarized femtosecond-laser pulses to achieve distinctive nanotexturing, which can be controlled by varying the number of pulses. The effective treatment of large areas of diamond surfaces under scanning mode leads to significantly enhanced absorptance in the visible range, paving the way for the development of metasurfaces for future diamond-based optoelectronic devices.