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Since some pathologies, such as cardiovascular or tumour diseases, have become some of the main causes of morbidity worldwide, a huge interest in the development of preclinical devices for their study has aroused during the past years. Their fabrication is a key factor for the study of these illnesses and it is directly linked with their pathological knowledge, early diagnosis and improvement of treatment.
Photonic crystals (PhCs) fabricated in the bulk of dielectric media have already been demonstrated to show a low-pass spatial (angular) filter functionality. [1] These PhC filters are fabricated in inorganic glasses through a femtosecond laser writing process. The most promising aspect of such filters is their direct integration into the cavities of laser micro-resonators. In particular, the integration...
The discovery of the formation of nanogratings when irradiating fused silica glass with ultrashort laser pulses in 2003 may have opened a new generation of compact and long life time optical devices. 3D-writing, thermal stability up to 1000 oC and virtually unlimited lifetime at room temperature make optics based on nanogratings of great potential for compact sensors or devices that work in adverse...
Exposure of silica glass to focused femtosecond laser radiation produces a variety of structural modifications [1] that are accompanied by a localized change in volume [2, 3]. This volume change can be used to apply displacements in a controlled manner, allowing the generation of intense, localized stress fields [4] whose magnitude, orientation, and shape are easily manipulated through tuning of the...
Ultrafast lasers in association to beam shaping have shown to be excellent candidates for transparent material processing [1]. Non-diffractive solutions such as Bessel beams allows for precise energy deposition since they are robust to undesired non-linear effects and as they do not distort along the propagation [2]. This offers important opportunities in laser-assisted cleaving, i.e. mechanical medium...
The development of mid-infrared (λ∼3–20 μm) integrated optical sensors has accelerated within the last years. The main driving interest is the potential of using photonic integrated elements capable of direct interaction with biomolecules and chemicals through their ground molecular vibrational modes, so that resonance fingerprints are exploited for novel sensor industrial applications. State-of-the-art...
Development on primary visible solid-state lasers (PVSSL) are very fascinating because the laser has many applications, for example, medicine, biology, and optical measurement systems. We have been developing a visible primary fiber laser with Pr-doped waterproof fluoro-aluminate glass fiber (Pr:WPFGF), and reported a single-mode laser performance in a double-clad structured Pr:WPFGF (Pr:DC-WPFGF)...
Liquid crystal (LC) devices are widely used as building blocks of many electro-optical systems including linear polarization rotators, dynamical wave plate retarders, and pixilated devices for displays, spatial light modulators, and tunable filters [1]. Precise alignment of the LC molecules is required for high quality components. The anisotropic nature of LC molecules allows them to align on solid...
For the first time, silver doping of bulk Gallium-Lanthanum-Sulphide (GLS) and Gallium-Lanthanum-Sulphur-Selenide (GLSSe) glass is demonstrated, presenting potential for a huge array of optoelectronic applications. Previously, silver doping of chalcogenide glasses were mostly based upon toxic, arsenic containing thin films [1-3]. GLS and GLSSe, however, offer a toxic free alternative, made by a safer...
Femtosecond laser machining combined with chemical etching offers an efficient and accurate way for producing complex three-dimensional structures out of fused silica. The versatility of the femtosecond laser machining together with the properties of fused silica makes it an ideal tool for integrating of micromechanical [1], microfluidic [2] and optical [3] devices, using the same fabrication method.
Ultrashort laser pulses have shown a huge potential for precise microstructuring. Apart from processing metallic samples [1], especially the possibility to realize three-dimensionally localized modifications within the bulk of transparent materials has gained significant interest. When intense ultrashort pulses are tightly focused into the transparent material, the intensity in the focal volume can...
In recent years, the fabrication, structural modification and characterisation of nanostructured materials have gained a great deal of attention due to their distinctive properties and potential use in technological applications. Glass containing silver (Ag) nanoparticles (NP), or Metal-Glass Nanocomposite (MGN), is routinely used as high-contrast optical polarisers [1], and has been recently shown...
The laser-induced periodic bulk nanograting structure inside of the material is one of the intriguing structure induced by the femtosecond laser pulses. Even now the formation mechanism of bulk nanogratings is also still a mystery [1, 2]. In the case of relatively simple composition glass (SiO2, GeO2, etc.), the subwavelength stripe-like regions of lower oxygen concentration including nanovoids exhibit...
Flame Hydrolysis Deposition (FHD) is a traditional route to deposit layers of doped silica onto the surface of a substrate for planar lightwave circuits. To form a uniform layer of fused glass the deposited soot must be consolidated, typically within a furnace at temperatures between 1200 °C and 1400 °C. This thermal processing is not localised as the temperature of the entire wafer is raised. This...
The controlled energy deposition by nonlinear absorption of ultrashort laser pulses offers a variety of different processing strategies for the machining of wide-bandgap materials. Considering laser-glass cutting applications, efficient single pass processes with volume modifications along the entire substrate thickness become possible using adapted focal field distributions [1]. The required extreme...
Femtosecond laser direct writing and micromachining attract considerable interest for a variety of applications ranging from integrated optics and microfluidics to printable flat optics and multi-dimensional optical data storage. A regular train of femtosecond pulses generated by femtosecond oscillator or regenerative amplifier does commonly used in laser material processing. Micromachining with sub-microsecond...
Being capable of light localization in the large air-filled core, microstructured hollow-core fibers (HCF) are highly promising for a long-distance high-power ultra-short pulse (USP) delivery due to extremely low fiber nonlinearity. Among them negative-curvature revolver hollow-core fiber (RHCF) having a cladding formed with a single layer of non-touched cylindrical silica glass capillaries [1] is...
At the Naval Research Laboratory (NRL), we are developing infrared glasses, ceramics and optical fibers for many active and passive applications. The chalcogenide glasses transmit from approximately 1 μm to 12 μm in the important infrared wavelength region. Fibers have been developed for passive applications, including light-pipes for remote chemical sensor systems for environmental pollution monitoring,...
Gradient index (GRIN) fibers have recently been identified as the potential next generation components for today's classic fiber optic applications, ranging from telecommunications to laser technologies [1]. In particular the nonlinear beam self-cleanup leading in multimode (MM) GRIN fibers to spatial organization into a fundamental mode on a weak background of higher order modes, is hoped to disrupt...
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