| Micro/nanofabrication technologies are very crucial for the fabrication of functional microstructures and devices, so to develop advanced microfabrication technologies is always highly desirable. Here, based on the basic principle of light and mater interaction, we systemically investigated two kinds of maskless laser microfabrication methods direct laser writing and laser interference lithography and realize high-quality micro-optical devices and large-area bio-inspired hydrophobic surfaces, which is an important step towards their broad applications. Moreover, a combined top-down/bottom-up technology was presented to obtain large-area, regular, controlled, functional, complex micro/nanostructures. Main contents were shown as follow:1. After carefully studying the present femtosecond laser direct writing technology, we proposed self-smoothing effect, improved scanning method and adopted nanoshell technology to solve some crucial problems of femtosecond microfabrication.(1) After investigating the factors of surface roughness, we presented several effective methods——stabilizing the laser power, precise scanning and surface self-smoothing effect to significantly improve the surface roughness of microstructures prepared by two photon polymerization. By this way, the surface roughness was decreased as small as 2.3 nm, which ensure the high quality of micro-optical devices. The dependence between scanning space and surface roughness was also systemically studied. This work is beneficial to further realize high-precision microoptical devices.(2) To enhance the smoothness of curved surface, we further proposed novel equal-arc scanning method and realize high quality curved microstructures, which is an important step for three dimensional complex microstructures. By optimal experimental parameters, low shrinkage resin and the method of stabilizing laser power, high quality aspherical microlens was realized and the measured profile curve agreed well with the theoretical one. The average error is as small as 20 nm.(3) We proposed nanoshell scanning in the solid resin SU8 to dramatically enhance the efficiency of femtosecond microfabrication while the device structures are still high-quality. Then, three dimensional complex microfluidic devices were rapidly realized. Moreover, functional micromachines were integrated into microchannels for special functions.2. We prepared high precision binary and three dimensional micro-optical devices by these improved methods and obtained excellent optical properties.(1) Phase type Fresnel zone plate (FZP) was prepared to realize high diffractive efficiency. The measured value reached 30%. Moreover, four level and eight level Fresnel lenses were realized to further enhance the efficiency to as much as 54% and 68%, respectively. By combining electroless plating Ag nanofilms on polymer FZP template, reflective FZP was realized for ultrashort wavelength light applications. The measured efficiency is 25.6%.(2) To improve the color dispersion of FZP, phase type fractal zone plate (FraZP), as a modified FZP, was proposed. FraZP could produce multifoci along the optical axis and realize excellent imaging ability. Experimentally, these improved functions were demonstrated. Moreover, high-level FraZP, just like high-level FZP, was prepared to realize high efficiency. The measured value reached36%, the largest value reported. These results demonstrated the high-precision and 3D microfabrication capability, which met the need of high quality micro-optical devices.(3) Based on previous binary microoptics, we used femtosecond laser direct writing to solve the critical problem——aspheric profile. By optimal design and appreciate parameters,100% fill factor microlens arrays were fabricated along the designed model. Moreover, high numerical aperture (-0.5) microlens arrays were demonstrated to obtain excellent focusing and imaging ability. Finally, due to high precision of femtosecond laser, these microlenses can be spatially arbitrarily positioned. For example, many microlenses were arranged into complex patterns "OLED" and "1+1=2", to meet various possible needs.(4) High quality artificial compound eyes were prepared by an improved laser scanning method and exhibited excellent focusing and imaging ability. Moreover, by an oil-immersion technology, the field-of-view was measured. The value reached as much as 90°, the largest value reported. By adjusting the height of the spherical base, the FOV could be precisely controlled.3. To solve the bad control of microstructures in present biomimetic surface, we firstly reported large-area bio-inspired hydrophobic surfaces by multi-beam laser interference lithography, such as multifunctional biomimetic materials, controllable anisotropic wetting, and smart tunable superhydrophobic surfaces. (1) We set up multibeam laser interference lithography system and fabricated regular needle arrays with large area (-600 mm2) within 3 min. After low-surface-energy modification, the surface showed both superhydrophobic ability and bright iridescence due to its regularity of these microstructures. Furthermore, by electroless plating Ag nanoparticles on the needle arrays, hierarchical structures are obtained to further enhance the contact angle to as many as 163°.(2) To better control the directional hydrophobic ability, we further study the anisotropic wetting. We firstly investigated the relationship between anisotropic wetting and grooves with different parameters - linewidth, period and height by laser interference lithography and found the strong dependence between the anisotropy and grooved height. This was interpreted by a thermodynamic model as a consequence of the increase of free energy barriers caused by the increase of the groove heights. According to the relationship, large-area controlled anisotropic surfaces were rapidly realized by adjusting the grooves' height which was simply accomplished by changing the resin thickness.(3) Hierarchal microstructures were prepared by modified laser interference lithography——intensity-modulation of four beams to investigate anisotropy wetting along both the parallel angleθ1 and perpendicular angleθ2. Then, theθ1 andθ2 could be simultaneously controlled by adjusting the height variation and the resin thickness that were determined by the spin-coating speed and the intensity ratio. Moreover, by combining appropriate design and low surface-energy modification, natural anisotropic rice leaf exhibiting CAs of 146°±2°/153°±3°could be realized by biomimetic anisotropic surface with the CAs 145°±1°/150°±2°.(4) We fabricated regular PDMS pillar arrays by combining interference lithography and nanoimprint lithography. Due to the flexibility of PDMS films, a novel tunable method curvature change by mechanical force was presented for the first time. Experimentally, we found the contact angle on the curved PDMS pillar arrays film increased from 150°to 160°when the mechanical force was exerted onto the flexible film. Most importantly, both of the adhesion force and the sliding angle on PDMS pillar arrays film significantly decreases as the curvatures increases. These studies revealed that three superhydrophobic states from Wenzel state to transitional state to Cassie state were reversibly switched by curvature change.4. Based on the above mentioned top-down technology, we further proposed a combined top-down and bottom-up method for various complex microstructures. Here, we presented laser interference lithography and capillary force assembly to realize regular, controlled microstructures with large-area. These flowerlike arrays could be used for some special functions, such as nanoparticles capture and release. Moreover, by changing various experimental parameters, we control the morphology of microstructures and obtained complex nanopatterns.
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