The exciting properties of micro-and nano-patterned surfaces found in natural species hide a virtually endless potential of technological ideas, opening new opportunities for innovation and exploitation in materials science and engineering. Due to the diversity of biomimetic surface functionalities, inspirations from natural surfaces are interesting for a broad range of applications in engineering, including phenomena of adhesion, friction, wear, lubrication, wetting phenomena, self-cleaning, antifouling, antibacterial phenomena, thermoregulation and optics. Lasers are increasingly proving to be promising tools for the precise and controlled structuring of materials at micro-and nano-scales. When ultrashort-pulsed lasers are used, the optimal interplay between laser and material parameters enables structuring down to the nanometer scale. Besides this, a unique aspect of laser processing technology is the possibility for material modifications at multiple (hierarchical) length scales, leading to the complex biomimetic micro-and nano-scale patterns, while adding a new dimension to structure optimization. This article reviews the current state of the art of laser processing methodologies, which are being used for the fabrication of bioinspired artificial surfaces to realize extraordinary wetting, optical, mechanical, and biological-active properties for numerous applications. The innovative aspect of laser functionalized biomimetic surfaces for a wide variety of current and future applications is particularly demonstrated and discussed. The article concludes with illustrating the wealth of arising possibilities and the number of new laser micro/nano fabrication approaches for obtaining complex high-resolution features, which prescribe a future where control of structures and subsequent functionalities are beyond our current imagination.

The significance of the magnitude of Prandtl number of a fluid in the propagation direction of induced convection rolls is elucidated. Specifically, we report on the physical mechanism to account for the formation and orientation of previously unexplored supra-wavelength periodic surface structures in dielectrics, following melting and subsequent capillary effects induced upon irradiation with ultrashort laser pulses. Counterintuitively, it is found that such structures exhibit periodicities, which are markedly, even multiple times, higher than the laser excitation wavelength. It turns out that the extent to which the hydrothermal waves relax depends upon the laser beam energy, produced electron densities upon excitation with femtosecond pulsed lasers, magnitude of the induced initial local roll disturbances and the magnitude of the Prandtl number with direct consequences on the orientation and size of the induced structures. It is envisaged that this elucidation may be useful for the interpretation of similar, albeit large-scale periodic or quasi-periodic structures formed in other natural systems due to thermal gradients, while it can also be of great importance for potential applications in biomimetics. PACS: 78.20.Bh 64.70.D-42.65.Re 77.90.+k The predominant role of convective flow in nonequilibrium spatial pattern formation has been demonstrated in various phenomena in nature such as on Earth's land and sea, as well as on planet's surface when large thermal or wind speed gradients are developed [1-4]. Similar fluid instabilities are also encountered in many industrial applications: heat exchangers [5] , evaporative cooling devices, and chemical vapor process [6], film flow in inclined porous substrates used in oil pipes [7], manufacturing of high purity semiconductor crystals [8].Similar patterns and more specifically, periodical structure formation are also induced on the surface or volume of many solids upon irradiation with laser beams [9][10][11]. This modification usually requires a solid to liquid phase transition followed by fluid movement and capillary effects. Whether classical Navier-Stokes equations and how a Newtonian fluid mechanics could determine quantitatively the characteristics of the molten material dynamics, still remain an open question.The formation of surface and bulk periodic structures gives rise to unique material properties and it has received considerable attention over the past decades due to a wide scope of applications regarding micro/nano-structuring of materials [12]. In this context, one timely area of exploration has been the ultrashort pulsed laser induced periodic structuring of dielectrics, due to its applicability in telecommunications, biomedicine and biomimetics [13][14][15][16][17]. The predominant physical mechanism to explain the formation of laser induced periodic surface structures (LIPSS) suggests that excited electron densities modify the dielectric constant and the refractive index n [18] leading to low spatial frequency LIPSS (LSFL). Alternative mechanisms to...

aiming to design and fabricate biomimetic structures. [7] Research in this field indicated several methodologies to develop bioinspired surfaces, exhibiting hierarchical structuring at the nano-and micro-lengthscales. [8][9][10][11] Laser fabrication is a maskless process allowing material modifications with a high precision over size and the shape of the fabricated features. [12] However, due to optical diffraction, the feature size resolution is limited to the order of wavelength (i.e., microscale); therefore, the challenge in biomimetic laser processing is to beat the diffraction limit and realize the structural complexity of natural surfaces, also, at the nanoscale. Materials' structuring using ultrashort (less than 1 ps) laser pulses, in particular, proved to be a precise and highly versatile tool to realize artificial surfaces that quantitatively mimic the morphological features and functionalities of their natural archetypes. [13][14][15][16][17][18][19] This capability comes as the outcome of the optimal combination of the ultrafast laser field and material properties that enable the production of features with sizes beyond the diffraction limit (i.e., nanoscale). A prominent example is the formation of self-organized subwavelength, laser-induced periodic surface structures (LIPSS), which have been proven an important asset for the fabrication of nanostructures with a plethora of geometrical features. [13,[20][21][22][23][24][25] This work is the first report on direct laser nanofabrication of biomimetic omnidirectional antireflective glass surfaces. It was inspired from the unique antireflection properties of the wings of the glasswing butterfly, Greta oto, and the Cicada Cretensis species. [2,3] This property is due to the presence of arrays (with periodicity in the range of 150-250 nm) of nonreflective nanosized (sub-100 nm size) pillars on both the top and the bottom surface of the wing. The current state-of-the-art technologies employed for the production of antireflection surfaces require either complex multiple steps and time-consuming procedures or chemical processes, [8,[26][27][28][29][30][31][32] which, in some cases, produce hazardous wastes. At the same time, the chemical coatings' quality tends to degrade with time. [27,33,34] Here, we demonstrate a single-step laser texturing approach for the structuring of biomimetic antireflective nanopillars, on fused silica glass (SiO 2 ) surfaces. The overall properties of the produced surfaces were found remarkably similar to the natural butterfly and Cicada archetypes, both in terms of the surface morphology Here, a single-step, biomimetic approach for the realization of omnidirectional transparent antireflective glass is reported. In particular, it is shown that circularly polarized ultrashort laser pulses produce self-organized nanopillar structures on fused silica (SiO 2 ). The laser-induced nanostructures are selectively textured on the glass surface in order to mimic the spatial randomness, pillar-like morphology, as well as the remarkable antir...