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Glasses based on SiO2-PbO-CdO-Ga2O3 system have been studied for the first time for fabrication of mid-infrared optical elements. Gallium oxide concentration was gradually increased, replacing silicon dioxide, for different cadmium and lead oxide content. The thermal and optical properties were investigated for different compositions. It was observed that the thermal stability, refractive index, and the transmission in the infrared range increased with increase of gallium and lead concentrations. The most thermally stable glass composition was selected for fabrication of optical elements such as optical fibers. We also successfully fabricated mid-infrared lenses by hot embossing for potential application in compact gas detectors.

We study optical performance of a vortex beam converter comprising a nanostructured gradient index vortex mask, a compact gradient index microlens and an optical fiber. The converter generates high quality focused optical vortex from the input Gaussian beam without support of any additional external optical elements. Integration of a nanostructured lens allows control of the size and the position of focus of vortex beams, while at the same time maintaining their quality. This confirms that nanostructured gradient index micro-optical components can be used sequentially to form complex optical systems and maintain full compatibility with fiber optics. Our experimental results are supported by numerical simulations.

The series of SiO2-Bi2O3-PbO-ZnO-BaO and SiO2-TiO2-Bi2O3-PbO-Na2O glasses were synthetized to obtain non-crystallizing materials, dedicated to fabrication of photonic crystal fibers. During composition development, the thermal properties were investigated according to the change of chemical composition. The glasses contain high concentrations of heavy metal oxides for high refractive index, large nonlinear refractive index and spectrally broad transmission window from 0.5 to 4.5 μm. Their thermal properties are optimized to enable drawing of all-solid glass photonic crystal fibers in tandem with previously designed highly nonlinear glass PBG81 based on SiO2-Ga2O3-Bi2O3-PbO-CdO system. This creates novel dual glass combinations for PCF fibers. We have also investigated influence of melting conditions on the final thermal and optical properties, including absorption from water contamination at around 2.8 μm.

We present composition development of borosilicate glasses for fabrication of high refractive index contrast, all-solid photonic crystal fibers. An oxide system composed of SiO 2 B 2 O 3 Al 2 O 3 Li 2 O Na 2 O K 2 O was adjusted to match thermal properties of selected highly nonlinear, lead bismuth gallium silicate glass. A high difference of refractive index of 0.376 is achieved at a wavelength of 1550 nm. We proved experimentally that the developed pair of glasses enables to draw optical fibers, and we propose a design of a photonic crystal fiber structure for broadband supercontinuum generation.

Novel fiber microprobe comprising a nanostructured gradient index optical vortex phase mask and single-mode fiber was investigated numerically and experimentally. The mask which, consists of spatially distributed sub-wavelength nanorods, was fabricated via the modified stack-and-draw fiber drawing technique. The mask has flat input and output surfaces and transverse dimensions of a standard single-mode fiber. The microprobe allows efficient generation of high-quality optical vortex beams in different environments such as air and water.

A new type of ultrathin fiber microprobe for selective electroporation is reported. The microprobe is 10 cm long and has a diameter of 350 µm. This microprobe is a low cost tool, which allows electroporation of an arbitrary selected single cell or groups of cells among population with use of a standard microscope and cell culture plates. The microprobe in its basic form contains two metal microelectrodes made of a silver-copper alloy, running along the fiber, each with a diameter of 23 µm. The probe was tested in vitro on a population of normal and cancer cells. Successful targeted electroporation was observed by means of accumulation of trypan blue (TB) dye marker in the cell. The electroporation phenomenon was also verified with propidium iodide and Annexin V in fluorescent microscopy.

The optical performance of nanostructured gradient index vortex phase masks (VPMs) in various external media was investigated. We utilized a modified stack-and-draw technique to fabricate the microscopic-size masks. Its structure contains spatially distributed sub-wavelength rods made of two thermally matched glasses with high and low refractive indices. Measured optical characteristics of the generated vortices with azimuthal phase distribution are presented. The numerical and experimental study shows that such VPMs with the same designed structure but varied thickness can convert fundamental light beam into optical vortices with different charges. Furthermore, we found that the mask performance is unaffected by the refractive index of the surrounding media making it an excellent candidate for microfluidic applications.

We study supercontinuum generation enhancement in an all-normal dispersion, all-glass photonic crystal fiber made of lead-silicate glasses. Dispersion characteristics were optimized through adjustment of regular hexagonal lattice of photonic crystal fiber in case of three different, thermally matched pairs of glasses. Supercontinuum generation was simulated with split-step Fourier method using the model that takes into account frequency-dependent effective mode area and losses, Raman response of the medium and temporal shape of the input pulse. An octave-spanning coherent supercontinuum has been obtained for all-glass fiber with lattice constant Λ = 1.73 μm and filling factor d/Λ = 0.8, made of silicate SF6/F2, spanning 850–2200 nm wavelengths in 10 dB dynamic range and pumped with pulses with energy as low as 3 nJ at 1550 nm.

In this work we present the results of our research on luminescent properties in the visible spectral rangeof two different composite materials – based on polymer (PMMA) and glass (B 2 O 3 –BaO–K 2 O) hosts dopedwith Er 3+ +Yb 3+ :Y 2 O 3 nanocrystallites. The luminescent properties of these two composites were carefullystudied on the basis of excitation and emission characteristics complemented by fluorescence dynamicsprofiles. The specific attention was given to the main deactivation mechanisms and up-conversionphenomena as well as analysis of the influence of host’s type on the optical properties of erbium ions. 2014 Elsevier B.V. All rights reserved. 1. IntroductionComposite materials, which are a combination of two phaseswith different optical and mechanical properties – for example, aglass or polymer matrix with embedded active nanocrystallites –may potentially enable designing and development the entirelynew class of light sources, combining advantages of small size,low cost and improved optical and mechanical properties. Thespecific nature of composite media allows obtaining the resultantfeatures non-observable in classical materials, like e.g. efficientemission (and lasing) in the short-wavelength spectral range inhigh-phonon oxide glasses or polymers. This, in turn, significantlyextends the area of possible applications in integrated optoelec-tronics, imaging systems, sensor networks, etc.The idea of the optical composite material is not new – the firstvitroceramic composites (based on glasses doped with crystallinephase) were developed in the late sixties by G.H. Beall and D.A.Duke in the Corning Glass Research & Development Laboratories[1]. The first reports about two-phase optically active materialsfor laser applications are dated back to the beginning of the 70s[2,3], and the first publications on the short-wavelength emissionin vitroceramic materials appeared in 1975 [4]. It should be noted,however, that despite many years of research, light sources basedon vitroceramic materials never have been applied commercially,which partly results from a complex and expensive technology oftheir manufacturing.Polymer materials are manufactured in a much simpler andlow-cost processes, therefore they have been tested with respectof luminescent and lasing properties from the very beginning ofthe development of laser technology. The first reports of researchon active nanocrystallites doped with rare earth ions dispersed inliquid polymer matrix can be found in R.S. Meltzer works of 2001[5,6]. The work of J. W. Stouwdam team results in constructionof the planar amplifier based on PMMA doped with Nd

Hot embossing is an attractive alternative to other micro-replication methods, since its cost effectiveness makes it suitable for mass-fabrication of wide range of elements. In this work, hot embossing is presented in context of fabrication of micro-optical elements made of soft glasses for near and mid infrared spectral region. Particular attention is given to the selection of suitable materials from which the mold is prepared, in order to minimize sticking and degradation of the embossing stamps. Refractive lens and diffractive gratings are successfully developed with the proposed approach.

In this paper we report on the development of small-diameter lenses in soft glass with transmission in infrared till 5 μm using hot embossing method. A fused silica stamps and in-house synthesized tungsten–tellurium–niobate and lead–bismuth–galate glasses are used for replication. Optimization process of hot embossing is presented. Optical properties of replicated lenses were characterized. Resolution of 50 lp/mm is obtained.

Three component PbO–Bi2O3–Ga2O3 glasses are characterized by high midIR transmittance, with a large susceptibility to crystallization. In this paper we investigate the increase in the thermal stability of these glasses by the addition of oxides such as GeO2, SiO2, Tl2O, CdO, Nb2O5. The resulting multicomponent glasses are well suited for the fabrication of microstructured fibers and micro-optical elements. The increased thermal stability of the modified multi-component glasses resulted in the IR absorption cut-off shifting to shorter wavelengths.

We present a dual mode, large core highly birefringent photonic crystal fiber with a photonic cladding composed of elliptical holes ordered in a rectangular lattice. The fiber is made of borosilicate glass and has a regular set of elliptical holes with an aspect ratio of 1.27 and a filling factor near 0.5. The group birefringence (G) and effective mode area were measured at 1550 nm for the fundamental mode and were found to equal 2 × 10−4 and 20 μm2 respectively. We discuss the influence of structural parameters including the ellipticity of the air holes and the aspect ratio of the rectangular lattice on the birefringence and on the fundamental and second modes of the fiber.

There is considerable interest in compact pulsed high peak power laser sources emitting at wavelengths near 1.55 μm. Rangefinders and other applications with free space propagation could be a benefit of such devices. The wavelength of around 1.55 μm is in the eyesafe regime where significantly higher pulse energies can be used without damaging human eyes. Erbium- and ytterbium-doped YAG single crystals were obtained by the Czochralski method. The basis conditions of growth and the results of optical homogeneity measurements of the obtained crystals are presented. This report describes also the effect of variations of erbium, ytterbium, chromium ions and glass base compositions on laser efficiency and the improved properties of a new glass base. The spectral properties and laser characteristics were investigated. Absorption spectra of Er 3+ - and Yb 3+ -doped active media were measured in the spectral range 190 to 5000 nm at room temperature. Excitation and luminescence spectra were also recorded at room temperature with a Jobin-Yvon spectrofluorometer using a diode laser (Polaroid 4300, 980 nm, 1 W) as an excitation source. The measurements of the lifetime of the Er 3+ ions in the upper laser level ( 4 I 13/2 ) of the samples were made by the direct method with pulse excitation.