Tailoring diamond’s optical properties via direct femtosecond laser nanostructuring

Abstract

We demonstrate a rapid, accurate, and convenient method for tailoring the optical properties of diamond surfaces by employing laser induced periodic surface structuring (LIPSSs). The characteristics of the fabricated photonic surfaces were adjusted by tuning the laser wavelength, number of impinging pulses, angle of incidence and polarization state. Using Finite Difference Time Domain (FDTD) modeling, the optical transmissivity and bandwidth was calculated for each fabricated LIPSSs morphology. The highest transmission of ~99.5% was obtained in the near-IR for LIPSSs structures with aspect ratios of the order of ~0.65. The present technique enabled us to identify the main laser parameters involved in the machining process, and to control it with a high degree of accuracy in terms of structure periodicity, morphology and aspect ratio. We also demonstrate and study the conditions for fabricating spatially coherent nanostructures over large areas maintaining a high degree of nanostructure repeatability and optical performance. While our experimental demonstrations have been mainly focused on diamond anti-reflection coatings and gratings, the technique can be easily extended to other materials and applications, such as integrated photonic devices, high power diamond optics, or the construction of photonic surfaces with tailored characteristics in general.

Quo Vadis LIPSS?—Recent and Future Trends on Laser-Induced Periodic Surface Structures

“… Improved regularity of LIPSS through surface overlayers: On dielectrics, the generation of large surface areas covered homogeneously with LIPSS is often very difficult when the single photon energy is significantly smaller than the band gap energy, i.e., when nonlinear absorption is required to couple the laser beam energy with the solid. Apart from the strategy to reduce the nonlinearity via the irradiation wavelength [ 82 ], another way to overcome this difficulty can lie in adding a very thin strongly-absorbing surface overlayer on the dielectric in order to facilitate resonant coupling effects of the laser radiation to the material underneath. For hexagonally arranged ablative nanobumps on glass, tens of nanometer thick copper and silver coatings were shown to be suitable [ 83 , 84 ].…”

Picosecond Laser Interference Patterning of Periodical Micro-Architectures on Metallic Molds for Hot Embossing

“…LIPSS [65,66,67,68], a universal phenomenon that occurs after laser irradiation on a wide number of different materials [69,70,71], have been found to exhibit different characteristic shapes, including ripples (lines), rods, cones, grooves, etc. The generation of LIPSS takes place commonly only in a fluence range close to the material damage threshold and even just below the ablation threshold [72].…”

Advances in ultrafast laser structuring of materials at the nanoscale

“…The periodicities, orientation, and their sizes render control on color organization and appearance, providing thus an optical marking effect [172,173,179], transferring information to color. The feature scale smaller the the wavelength can sample and scatter the optical field and create further effects, among them the generation of antireflective properties [25,180,181]. Laser-induced microcone-like structures on semiconductors [24,182] (see example in Figure 1(k)), similar to what can be produced by reactive etching, outperform current capacities for harvesting photons for sensors and photovoltaic applications, showing increased absorptivity down to the infrared spectral domain [183].…”