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We report on the fabrication of highly ordered, multi-directional, complex surface structures that mimic the unique morphological features of certain species found in nature. In particular femtosecond laser pulses with various polarizations states, such as circular and vectorial, were utilized for structuring metal and dielectric surfaces. Experimental results showed that the direction of LIPSS in...
Due to their low-cost, comparable transparency and ease of preparation, polymers are widely used to fabricate various micro- and nano-structures for their applications in micro-optics, micro-fluidics, biomedical systems and so on. And in recent years, femtosecond (fs) laser direct writing process has become a popular tool to fabricate arbitrary three-dimensional (3D) microstructures with nanometer...
Terahertz (THz) sources are indispensable for various applications such as THz time-domain spectroscopy. A promising approach to generate broadband THz radiation is to employ laser-induced gas plasmas, which has already been demonstrated for various settings [1, 2]. In order to miniaturize such sources, it has been proposed to exploit single-color laser-induced microplasmas [3]. Then, a conical THz...
Thin metal wires are known to be a low loss and very low dispersion terahertz (THz) waveguide [1]. Recently, generation of a strong THz surface wave was demonstrated by irradiating a wire surface with a ultrahigh intensity femtosecond laser [2]. Such THz light sources driven by femtosecond laser induced plasma are expected to have a high potential as a power scalable source. However, the characteristics...
Compact monolithic single-mode red emitting diode lasers are still not readily available for many wavelengths in the visible spectrum. Strontium lattice and Calcium clocks are some of the most widely investigated optical clocks worldwide and the pertinent transitions wavelengths required are in the red and blue wavelength spectral region. The current state of the art in laser technology employs external...
In the past years rare-earth-doped fiber lasers have emerged as attractive and power scalable solid-state laser concept due to the outstanding thermo-optical properties of an actively doped fiber. The large ratio of surface to active volume of such a fiber ensures excellent heat dissipation, furthermore the beam quality is defined by the refractive index profile of the active core and is therefore...
There is a growing interest in the use of metal halide perovskites with different compositions as highly efficient light emitters among the whole visible spectral region [1]. Several groups have observed amplified spontaneous (ASE) emission in thin perovskite films. The gain and threshold values for ASE are very promising, motivating the current effort to develop practical devices that lase.
Surface nano- and microstructuring with additive and subtractive lithography techniques are commonly used in nanotechnology and photonics, while nanoimprint lithography and nanosphere lithography are used for creating periodic structures for plasmonics applications. Single step, maskless optical patterning techniques also exist, notably multi-beam interference based techniques and Laser Induced Periodic...
Ultra-short pulse (USP) Laser Induced Periodic Surface Structures (LIPSS) namely ripples, micro-grooves and spikes [1] have received considerable attention since they can modify some key surface properties like wettability, colour and tribology, increasing the material's internal value [2]. Nevertheless, the complete understanding of the physical mechanisms leading to LIPSS formation is still under...
Indium Tin Oxide (ITO) is a highly conductive and transparent thin film used in modern technological applications; i.e organic light emitting devices (OLED) [1], transparent flat touch panel displays (FPD) [2], and solar cells [3]. Fast and highly precise selective patterning of ITO with controlled depth and width of scribed lines, is required for such applications. The pattering for such applications...
It has been demonstrated that cell adhesion on biocompatible materials is modified when the surface of the material is structured instead of being totally polished [1-3]. An efficient way to texture surfaces is using the foci of a microlens array and a direct write laser technique [4]. Due to the short focal length of the microlens, they can be damaged by expelled material during ablation. In previous...
Few-cycle femtosecond pulses (∼10 fs) have proven their interest in highly-controlled interaction with dielectric materials [1]. For efficient single-shot ablation, intensities exceeding 1014 W/cm2 at the target surface are required. However, for such intensities, working in air ambience rapidly yields significant nonlinear spatial distortion of the beam in the pre-focal region, or even air ionization,...
We experimentally and theoretically examined the mode structure of half-disk lasers fabricated by cleaving whispering gallery mode (WGM)-disk lasers. The WGM lasers with a radii R of 50–150 μm emitting near 2.2 μm were fabricated using the GaSb-based quantum well structure [1]. The cleavage usually passes not through the centre of the disk with the deviation δ/R up to 20 % (Fig. 1a). Recently we have...
Thin metal wires are known to be a low loss and very low dispersion terahertz (THz) waveguide. Recently, generation of a strong THz surface wave was demonstrated by irradiating a wire surface with a ultrahigh intensity femtosecond laser [1]. Such THz light sources driven by femtosecond laser induced plasma are expected to have a high potential as a power scalable source. Picosecond magnetic field...
Ultrafast laser inscription (ULI) allows the fabrication of compact, highly-efficient and robust laser sources over a broad range of crystalline, ceramic and glass gain media. For instance, subsurface waveguides can be formed by the stress induced refractive index modification effect which takes place between two parallel modified regions referred to as “Type II” guiding [1]. Previously, a family...
The possibility to control surface properties of materials and to tailor behaviour of cells and biomolecules are the basic requirements in the development of a new generation biomaterials for applications in tissue engineering. Surface patterning on micro and nano-scale is critical to distinguish the effects of cell shape, focal adhesion, and ligand input for cell functions. Recently, much attention...
Diamond substrates and films have been adapted for many uses because of the material's exceptional properties such as the highest thermal conductivity, high mechanical hardness, wide bandgap, very good optical properties, chemical resistance and biocompatibility. On the other hand, in the last few years, the femtosecond (fs) laser technology has seen a considerable growth in scientific and manufacturing...
Optical frequency combs from ultrafast lasers have revolutionized the field of optical metrology and photonics. However, today's commercial frequency combs are still based on complex and expensive ultrafast laser systems, which prevent applications for cost-sensitive areas. Among emerging technologies, modelocked semiconductor lasers are highly promising for future low-cost high-volume production...
Yttria stabilised zirconium oxide (YSZ) is a very important class of ceramic with unique mechanical and electrochemical properties. For this reason, YSZ is been widely used in oxygen sensors and solid oxide fuel cells (SOFC). Among the different SOFC configurations, the electrolyte-supported one exhibits better mechanical robustness and resistance to redox cycles than the electrode-supported configuration...
High-energy pulsed mid-infrared (IR) lasers in the 2 to 3 μm range are of interested for various scientific and industrial applications such as laser radar, chemical sensing, and mid-IR laser processing. In addition the sources are useful as a pump light source for generating mid-IR waves longer than 4 μm in optical parametric oscillation. Cr:CdSe is one of attractive laser mediums for the efficient...
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