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This paper presents a study of the behaviour as optical superlattices of periodically poled LiNbO3 and LiTaO3 crystals using the Scanning Near-field Optical Microscopy (SNOM) technique. The periodic ferroelectric domains were formed either by electric field poling technique or by the “off-centre Czochralski method” during crystal growth. SNOM patterns were recorded in both collective and reflective configuration, simultaneously with surface topography measurement by AFM (Atomic Force Microscopy). It has been found that regardless of the method used to create the domains, a modulation in the SNOM signal intensity is correlated with the ferroelectric domain structure. The maximum intensity of the collected or reflected SNOM light intensity is centred on the negative domains, whereas the minimum intensity is positioned on the positive domains. This result demonstrates that the modulation of the refractive index is related to the domains and not with the wall between them.

The aim of this paper was to develop a biomechanical model to reproduce the viscoelastic behaviour of the material of the bovine temporomandibular joint (TMJ) disc, as a substitute material to be applied in subsequent experimental studies of possible human TMJ disorders. As the mechanical properties of the disc change due to different factors, this study is focussed on evaluating its viscoelastic response under compression in stress–relaxation, creep and cycling loading tests, using an equipment that allows us to simulate the real function conditions of the material in a liquid medium at 37 °C. In order to fit the data obtained from the relaxation and creep tests, generalised Maxwell and Kelvin models of eight terms are proposed, leading to Prony’s series of practical interest for subsequent numerical calculations.

We show how the ultrafast laser inscription of nanodimple arrays enables near-field local enhancement in high refractive-index crystals. We first demonstrate both experimentally and numerically how, when two nanodimples are separated by intermediate distances (700–1000 nm), near-field interference can take place resulting in a near-field enhancement between nanodimples. Based on this effect, near-field enhancements close to 60% are then demonstrated at the center of nanodimple arrays, and strong optical contrasts in excess of 100% are produced. The integration of these arrays into crystal substrates provides a versatile tool for new optical trapping and evanescent-field nanosensing devices.

This paper presents a study of the near-field optical profile of corrugated surfaces obtained from commercial digital versatile disk (DVD) patterns using a scanning near-field microscope (SNOM). The profile of the SNOM light intensity collected is related to the topography of the samples. The SNOM patterns consist of a periodic modulated light intensity along the corrugated surface with the same periodicity of the topography structure. For the virgin sample, the light profile has intensity peaks corresponding to the ridges of the DVD structure. However, when the corrugated surface is metalized with a thin gold film of 30 nm thick, the SNOM light intensity peaks are centred in the valley of the DVD structure. A Finite-Difference Time-Domain (FDTD) model has been employed to simulate the SNOM experimental data.

This work shows a study of the periodic ferroelectric domains formed in LiNbO3 crystals doped with rare earths by means of scanning near field optical microscopy (SNOM) technique. It has been observed periodic structures associated with ferroelectric domains with an unexpected high value of the optical contrast working under reflectance SNOM mode. From Raman-Nath diffraction patterns, a refractive index modulation of Δ n ∼ 1 0 − 4 has been calculated. These results were correlated with the ferroelectric periodic domains obtained by the SNOM technique. A light waveguide effects along the ferroelectric domains is suggested to explain the high reflectance contrast observed in SNOM experiments.

The effect that femtosecond laser filamentation has on the refractive index of Nd:YAG ceramics, and which leads to the formation of waveguide lasers, has been studied by micro-spectroscopy imaging, beam propagation experiments and calculations. From the analysis of the Nd3+ luminescence and Raman images, two main types of laser induced modifications have been found to contribute to the refractive-index change: (i) a lattice defect contribution localized along the self-focusing volume of the laser pulses, in which lattice damage causes a refractive-index decrease, and (ii) a lattice strain-field contribution around and inside the filaments, in which the pressure-driven variation of the inter-atomic distances causes refractive-index variations. Scanning near-field optical-transmission and end-coupling experiments, in combination with beam propagation calculations, have been used to quantitatively determine the corresponding contribution of each effect to the refractive-index field of double-filament waveguides. Results indicate that the strain-field induced refractive-index increment is the main mechanism leading to waveguiding, whereas the damage-induced refractive-index reduction at filaments leads to a stronger mode confinement.

Near-field-optical-microscopy has been used to study the micro-modifications caused by femtosecond laser pulses focused at the surface and in the volume of lithium niobate crystals. We have found experimental evidence of the existence, close to femtosecond ablation craters, of periodic modifications in the surface reflectivity. In addition, the potential application of near-field-optical microscopy for the spatial location of permanent modifications caused by femtosecond pulses focused inside lithium niobate crystals has been also demonstrated.

In this work, Scanning Near Field Microscopy (SNOM) observation and characterization of quasi-periodic ferroelectric domains in rare earth doped LiNbO 3 , Nd doped Ba 2 NaNb 5 O 15 , and LiTaO 3 crystals are presented. The formation of ferroelectric domains has been induced either during the crystal growth procedure (LiNbO 3 and Ba 2 NaNb 5 O 15 ) or by applying pulsed electric field (LiTaO3). SNOM reflection, transmission and collection modes have been used indistinctly to characterize the ferroelectric domain structure. In the three crystals under study, an unexpected optical contrast associated to the presence of ferroelectric domains has been observed. In particular, working in the SNOM collection mode the optical contrasts reached a value closed to ∼ 80% in Ba 2 NaNb 5 O 15 and LiTaO 3 crystals. These high optical contrast values are explained considering that the ferroelectric domains pattern operates as a periodic array of planar waveguides (optical super-lattices). The invoked light-pipe mechanism...

In this paper we report on experimental evidence of laser light confinement between ferroelectric domains in the neodymium doped Ba2NaNb5O15 ferroelectric crystal. High contrast near field optical microscopy images have been obtained as a consequence of the periodic modulation in the refractive index caused by the presence of 2D antiparallel ferroelectric domains.

The simulation of light propagation using standard beam propagation techniques, in periodically inverted domains in Ba2NaNb5O12 crystals is presented. The poled domains pattern gives rise to periodic modulation of the refractive index in the crystal, which can be observed with diffraction experiments and simulated by one-dimensional beam propagation methods. The micro-domains are characterized by Scanning Near Field Microscopy, using both transmission and collection modes. In particular, under the collection mode, micro- pictures have been obtained with unexpected high optical contrast between positive and negative domains of up to 80%. Using a beam simulation method, the results are explained considering that the ferroelectric domains operate as a periodic array of planar waveguides.

In this work near-field optical measurements of a corrugated grating coated with a 30 nm thick gold film are presented. The grating was made using the polycarbonate corrugated substrate of a commercially available recordable CD as template. This has been proved to be a versatile and low cost technique in producing large 1.6 μm period gratings. The study was carried out using a Scanning Near-Field Optical Microscope (SNOM) working in both collection and reflection modes at two different wavelengths, 532 nm and 633 nm. The results illustrate that the intensity patterns of near-field images are strongly polarization-dependent, even showing different periodicity of the localized fields for orthogonal polarization states. When electric field of the light is polarized parallel to the grooves, the periodicity of the SNOM images is coincident with the grating period, whereas when the light is polarized perpendicular to the grooves the SNOM pattern shows a periodicity twice that of the corresponding topography of the grating. Numerical simulations of the SNOM data based on a two-dimensional Finite Difference Time-Domain (2D-FDTD) model have been realized. The results of the simulations are in good agreement with the experimental data, emphasizing the need of performing numerical simulation for the correct interpretation of SNOM data, This work has been partially supported by Ministerio de Ciencia e Innovacion (project TEC2010-21574-C02-01) and Comunidad de Madrid (P2009/TIC-1476), Spain. E. Camarillo G. recognizes to DGAPA-UNAM support for a sabbatical year at UAM

Objective Acromegaly is often associated with sleep apnea-hypopnea syndrome (SAHS). The purpose of this study was to understand the prevalence of SAHS in patients with acromegaly and define the characteristics of acromegalic patients with and without SAHS. Patients and methods The study enrolled 17 patients (11 women and 6 men) residing in the province of Ourense, Spain, who were diagnosed with acromegaly. All patients underwent overnight polysomnography in a sleep laboratory. In addition, growth hormone and insulin-like growth factor 1 levels were assessed. Sixteen of the patients underwent cephalometric study. Results The average age of the patients was 58 years (95% confidence interval [CI], 52-63). The average body mass index was 31 (95% CI, 29-34) and average neck circumference was 41 (95% CI, 39-43). Ten patients (58.8%) had an apnea-hypopnea index (AHI) greater than 10. Nine had obstructive apnea and one had central apnea. Seven (5 with an AHI>10 and 2 with an AHI 10 and Epworth>10). No correlation was found between an AHI greater than 10 and hormonal activity ( P = .082). The mean growth hormone level for patients with an AHI greater than 10 was 4.8 (95% CI, 0.5-9) and the mean for those with an AHI less than 10 was 12 (95% CI, 2-27). Fifty percent of the patients were treated with a somatostatin analog and half of those treated exhibited apnea ( P = .302). No cephalometric differences related to the presence of apneas were found. Conclusions We found a high prevalence of sleep apneas (58.8%) and SAHS (29.4%), and central apneas were rare. We found no correlation between hormone activity level and the presence of SAHS. The incidence of SAHS was the same in somatostatin analog treated and untreated patients. Cephalometric variables did not distinguish between acromegalic patients with and without SAHS.

Objetivo La acromegalia se relaciona frecuentemente con el sindrome de apnea-hipopnea del sueno (SAHS). El proposito de este trabajo es conocer la prevalencia del SAHS en los pacientes con acromegalia y definir las caracteristicas de esta poblacion con y sin SAHS Pacientes y metodos Se estudio a 17 pacientes diagnosticados de acromegalia en la provincia de Ourense (11 mujeres y 6 varones). A todos ellos se les realizo polisomnografia nocturna diagnostica en el laboratorio del sueno, ademas de una determinacion de hormona de crecimiento y de factor 1 de crecimiento insulinalike, y a 16 se les efectuo un estudio cefalometrico Resultados La edad media de los pacientes era de 58 anos (intervalo de confianza [IC] del 95%, 52-63). La media del indice de masa corporal era de 31 (IC del 95%, 29-34) y la del perimetro del cuello, de 41 (IC del 95%, 39-43). Diez pacientes (58,8%) tenian un indice de apnea-hipopnea (IAH) mayor de 10; 9 presentaban apnea obstructiva y 1, central. Del total de pacientes, 7 (5 con IAH > 10 y 2 con IAH 10 y Epworth > 10) 5 pacientes (29,4%). No se encontro relacion entre un IAH mayor de 10 y actividad hormonal (p = 0,082). Los sujetos con IAH mayor de 10 presentaban un valor medio de hormona de crecimiento de 4,8 (IC del 95%, 0,5-9) y en aquellos con IAH menor de 10 dicho valor era de 12 (IC del 95%, 2–27). Estaban tratados con analogos de la somatostatina el 50% de los pacientes, de los cuales la mitad presentaba apnea (p = 0,302). El estudio completo de las cefalometrias no evidencio diferencia en relacion con la presencia de apneas Conclusiones Encontramos una alta prevalencia de apnea del sueno (58,8%) y de sindrome de apnea del sueno (29,4%), y fue una rareza la presencia de apneas centrales. No encontramos relacion entre actividad hormonal y la presencia de SAHS. Los pacientes tratados con analogos de la somatostatina presentaban la misma incidencia de SAHS que los no tratados. Ningun parametro de cefalometria resulto discriminador

Objetivos Conocer la situacion real de los especialistas en neumologia y cirugia toracica en el marco de la red sanitaria publica espanola Sujetos y Metodo Teniendo en cuenta la base de datos de la Secretaria de la SEPAR del ano 1999, se recopilo informacion de 326 hospitales espanoles. Se pudo obtener, asi, la composicion de las plantillas de las secciones o servicios de neumologia y cirugia toracica de los mismos. Los resultados se expresaron como proporciones simples en lo referente a su distribucion por edades, cargos y autonomias. Ademas, se calcularon las tasas por 100.000 habitantes en cada comunidad (datos de poblacion segun el Instituto Nacional de Estadistica del ano 1997) Resultados Se evaluo un total de 1.786 medicos (1.245 neumologos, 185 cirujanos y 356 pertenecientes a otras especialidades). La edad media fue de 41 ± 9 anos para los neumologos, 44 ± 10 anos en el grupo de cirujanos y 51 ± 8 anos en el resto. La distribucion por comunidades autonomas fue desigual, encontrandose un maximo de 6,66 neumologos y 0,9 cirujanos/100.000 habitantes en Asturias y Madrid, respectivamente, y un minimo de neumologos en Murcia y de cirujanos toracicos en Extremadura (1,4 y 0/100.000 habitantes, respectivamente) Conclusiones La situacion de las especialidades de neumologia y cirugia toracica es deficitaria en muchas provincias y comunidades autonomas de nuestra geografia. En este sentido, el mercado profesional no esta saturado, por lo que parece haber unas buenas perspectivas laborales para los futuros especialistas

A characteristic of the glass is its fragility and the scatter of the experimental mechanical strength due to the presence of defects that appear in the process of manufacturing or handling. Accordingly, investigations on this material were priorly conducted to improve the processes of manufacturing and to establish design methodologies based on probabilistic approaches. The influence of mode II of loading was traditionally ignored or considered as ratio of mode II. Recent studies have shown that when a shear-loaded crack becomes unstable a new compressive stress concentration field builds up in the notch formed between the original crack and the branch crack. This stress field affects the energy balance and also the beginning of crack extension. A procedure to design glass elements was developed jointly with CIDA of Cristalería Española, S.A. The aim of this work is to improve the model by the consideration of a mixed mode loading and its experimental contrast.Una de las características del vidrio es su fragilidad y la gran dispersión de sus valores de resistencia mecánica, motivado fundamentalmente por la presencia de defectos procedentes de su fabricación o de su manipulación. Como consecuencia, las investigaciones en este material se han dirigido preferentemente a la mejora de los procesos de fabricación y al establecimiento de metodologías de diseño basadas en modelos probabilísticos. Tradicionalmente, en el análisis de la rotura se ha despreciado la influencia del modo II o se ha representado como un porcentaje del modo I. Recientes estudios demuestran la aparición de un nuevo campo de tensiones de compresión cuando una fisura crece bajo una carga en modo II puro situado en el codo que se forma entre la fisura original y su ramificación. Este campo de compresión influye en el equilibrio energético y, en consecuencia, en la predicción de la rotura. En colaboración con el CIDA de Cristalería Española, S.A. se ha desarrollado un procedimiento para el dimensionamiento probabilista de elementos de vidrio plano para edificación. En este artículo se propone ahora una mejora del modelo, considerando la existencia de un modo mixto de carga y procediendo posteriormente a su contraste experimental.

The surface morphology of the ablation craters generated in LiNbO3 by 130 fs laser pulses at 800 nm has been investigated by AFM/SNOM microscopy. The single pulse fluence corresponding to the ablation threshold has been estimated to be ≈1.8 J/cm2. A complex structure including random cone-shaped protrusions is observed inside the ablated crater. The scale of the protrusion spacing is in the submicron range and the heights are typically of a few tens of nanometers. At and outside the crater rim a novel quasi-periodic wave-like topography pattern is observed in both types of microscopy techniques. The average wavelength, that is slightly dependent on pulse fluence, is (500-800 nm) comparable to the light wavelength. This novel topography feature keeps a close similarity with a Fresnel diffraction pattern by an absorbing circular obstacle or impact wave pattern produced by a combination of heat and shock wave (resemble that of impact crater). It is proposed that the obstacle is associated to the strongly nonlinear multiphoton absorption at the peak of the pulse profile. The energy deposited by nonlinear absorption of such profile causes ablation of both the crater and the rippled structure. © 2008., This work has been partially supported by the Spanish Ministerio de Ciencia y Tecnología (proyect MAT2005-05950 MOISES) and by the Comunidad Autónoma de Madrid (project S-0505-TIC-0191 MICROSERES).

A near-field scanning optical microscope (NSOM) is used to perform structural and optical characterization of the surface layer after Zn diffusion in a channel waveguide fabricated on lithium niobate. A theoretical approach has been developed in order to extract refractive index contrast from NSOM optical transmission measurements (illumination configuration). As a result, different solid phases present on the sample surface can be identified, such as ZnO and ZnNb2O6. They appear like submicrometric crystallites aligned along the domain wall direction, whose origin can be ascribed to some strain relaxation mechanism during the annealing process after Zn diffusion. Jose.Canet-Ferrer@uv.es

Relevant damage features associated with femtosecond pulse laser and swift-ion irradiations on LiNbO3 crystals are comparatively discussed. Experiments described in this paper include irradiations with repetitive femtosecond-laser pulses (800 nm, 130 fs) and irradiation with O, F, Si, and Cl ions at energies in the range of 0.2-1 MeV/amu where electronic stopping power is dominant. Data are semiquantitatively discussed by using a two-step phenomenological scheme. The first step corresponds to massive electronic excitation either by photons (primarily three-photon absorption) or ions (via ion-electron collisions) leading to a dense electron-hole plasma. The second step involves the relaxation of the stored excitation energy causing bond breaking and defect generation. It is described at a phenomenological level within a unified thermal spike scheme previously developed to account for damage by swift ions. A key common feature for the two irradiation sources is a well-defined intrinsic threshold in the deposited energy density Uth required to initiate observable damage in a pristine crystal: Uth ≈1.3× 104 -2× 104 J/ cm3 for amorphization in the case of ions and Uth ≈7× 104 J/ cm3 for ablation in the case of laser pulses. The morphology of the heavily damaged regions (ion-induced tracks and laser-induced craters) generated above threshold and its evolution with the deposited energy are also comparatively discussed. The data show that damage in both types of experiments is cumulative and increases on successive irradiations. As a consequence, a certain incubation energy density has to be delivered either by the ions or laser photons in order to start observable damage under subthreshold conditions. The parallelism between the effects of laser pulses and ion impacts is well appreciated when they are described in terms of the ratio between the deposited energy density and the corresponding threshold value. © 2008 American Institute of Physics.

The micro-structural modifications induced by femtosecond laser ablation of Nd:YAG crystals has been studied by near field optical microscopy. Results have been compared to those obtained from micro-luminescence experiments.

8 págs.; 5 figs., © 2015 The Association for Research in Vision and Ophthalmology, Inc. PURPOSE. Successful intraocular lens procedures, that is, implantation of accommodating intraocular lenses (A-IOL), require firm engagement of the IOL haptics to the capsular bag. We evaluated the use of photochemical bonding to engage IOL materials to the capsular bag. METHODS. Freshly enucleated eyes of New Zealand rabbits were used in two types of photobonding experiments using Rose Bengal (RB) photoinitiation and green light (532-nm) irradiation. First, RB-stained capsular bag strips were photobonded ex vivo to IOL polymer [poly(2-hydroxyethyl methacrylate) pHEMA] strips in an atmosphere of air and of nitrogen. Second, IOLs were implanted intracapsularly and photobonded intraocularly. Irradiation times were between 30 and 180 seconds, and laser irradiance was between 0.25 and 0.65 W/cm2. The strength of the bonding was tested using a custom-developed uniaxial extensiometry system and the breakage load (the load that caused breakage per bonded area) was calculated. RESULTS. The breakage load of ex vivo capsule–pHEMA bonds increased exponentially with irradiation time, using 0.45 W/cm2. In air, the average breakage load across all conditions was 1 g/mm2 and 1.6 times lower than that in a nitrogen atmosphere. Intraocularly, RB-stained IOLs were strongly photobonded to the capsule bag with breakage loads > 0.8 g/mm2. CONCLUSIONS. Breakage of the photobonded linkage between IOL material and capsular bag required loads substantially greater than the maximum force of ciliary muscle, suggesting that this technology may introduce a new paradigm for engagement of A-IOLs. The bonding produced in air was stronger than that in nitrogen atmosphere, suggesting that oxygen is involved in the chemical mechanism for photobonding., Supported by European Research Council (ERC) EU Seventh Framework Program (FP/2007-2013)/ERC grant agreement, ERC- 2011-AdC 294099 (SM), Spanish Government Grants FIS2011- 25637 (SM) and FIS2013-49544-EXP (CD), and Juan de la Cierva postdoctoral fellowship (JL).

Alexithymia is a psychological trait characterised by difficulty in perceiving and expressing emotions and body sensations. Failure to perceive dyspnoea could lead alexithymic asthmatics to underestimate the severity of an asthma exacerbation, and thereby increase the risk of developing a fatal or near-fatal asthma (NFA) attack. The objective of the present study was to determine the prevalence of alexithymia in NFA patients and to analyse their clinical characteristics. Alexithymia was assessed using the Toronto Alexithymia Scale in this multicentric prospective observational study. From 33 Spanish hospitals, 179 NFA patients and 40 non-NFA patients, as a control group, were enrolled. There was a higher proportion of alexithymia in the NFA group than in the non-NFA group (36 versus 13%). Patients with NFA and alexithymia were older than the rest of the NFA group, and had a lower level of education, a higher level of psychiatric morbidity, a higher proportion of severe persistent asthma and a greater number of prior very severe asthma exacerbations (49 versus 27%). Alexithymia, severe persistent asthma and a low level of education were identified as independent variables related to repeated very severe asthma exacerbations. The results show that alexithymia is more frequent in near-fatal asthma patients compared to the rest of asthmatics and is associated with recurrent very severe asthma exacerbations.

Specialised tuberculosis out-patient clinic covering a population of 350 885.To compare two techniques, ultrasonic nebuliser (UN) and Venturi-type face mask nebuliser (VFMN), for obtaining sputum in patients suspected of having active pulmonary tuberculosis (PTB) and who cannot expectorate, and to analyse the usefulness and cost of sputum induction with UN in a specialised medical practice.Prospective study from October 1997 until March 2000.Of 94 subjects who completed all tests, at least one sample of sputum was obtained from 89 (95.6%). UN provided adequate samples in 86 (93.4%) and VFMN in 66 (71%), a significant difference (P0.001). Among 43 patients diagnosed with active PTB, the diagnosis was confirmed in 39 with the samples obtained by sputum induction. Direct acid-fast bacilli smear was positive in 8 (19%). Direct costs were low and the technique can be performed on the day the patient attends the outpatient clinic.Sputum induction with an ultrasonic nebuliser was well-tolerated, of low cost, allows adequate samples to be obtained in the majority of patients who cannot produce sputum, and was more effective than the Venturi-type face mask.

To study the real situation of respiratory medicine specialists and chest surgeons in the Spanish health service.Using the database of the secretary of the Spanish Society of Respiratory Medicine and Chest Surgery (SEPAR) for 1999, we gathered data on 326 Spanish hospitals. We were thus able to ascertain the level of staffing of respiratory medicine and chest surgery departments. The results were expressed as simple percentages showing distribution by age, duties and geographic area. The number of specialists per 100,000 inhabitants in each community was also calculated based on population data provided by the National Statistics Institute for 1997.We studied 1,786 physicians or surgeons (1,245 pneumologists, 185 surgeons and 356 from other specialties). The mean age was 41 9 years for pneumologists, 44 10 years for surgeons and 51 8 years for the others. We observed unequal distribution by geographic area, with a high of 6.66 pneumologists and 0.9 surgeons per 100,000 inhabitants in Asturias and Madrid, respectively and a low of 1.4 pneumologists per 100,000 inhabitants in Murcia and 0 surgeons in Extremadura.Specialist coverage by pneumologists and chest surgeons is inadequate in many provinces and communities in Spain. The professional market is not saturated, indicating that future specialists can look forward to market demand.

Peritoneal dialysis solutions containing icodextrin are ideal for providing sustained ultrafiltration during long dwells, and they have replaced high glucose for long dwells in some patients. The biocompatibility of these solutions, especially in regard to glucose degradation products, has not been studied in depth. The object of this study was to compare the effects of commercially available dextrose-containing dialysis solutions to those of icodextrin-containing solutions on fibroblast proliferation in vitro. We measured the effect of solutions on cell growth by exposing murine fibroblasts to pH-adjusted test solutions mixed with culture medium, and by comparing cell growth to growth in culture medium only. No statistical difference was observed in the growth of cells exposed to heat-sterilized Extraneal [7.5% icodextrin (Baxter Healthcare, Deerfield, Illinois, U.S.A.)], heat-sterilized Dianeal [1.5% dextrose (Baxter Healthcare)], or filter-sterilized Dianeal [4.25% dextrose (Baxter Healthcare]. Also, no difference was observed in the growth of fibroblasts exposed to heat-sterilized Extraneal or to filter-sterilized Extraneal, but heat-sterilized Dianeal [4.25% dextrose (Baxter Healthcare)] caused a significant reduction in cell growth. Glucose degradation products (GDPs) are known to contribute to reduced cell growth in vitro. Extraneal had lower levels of the GDP acetaldehyde compared to Dianeal (2.5% or 4.25% dextrose). The results demonstrate enhanced in vitro biocompatibility characteristics for Extraneal, possibly related to low GDP levels in Extraneal.

We report on femtosecond laser writing of channel waveguides in Nd(3+) ion doped YAG ceramics by multiple inscriptions of damage filaments. Waveguiding between filaments was found to resist annealing temperatures as high as 1500 degrees C. Microluminescence imaging experiments have been carried out to elucidate the potential application of the obtained waveguides as integrated laser sources as well as to elucidate the waveguiding mechanisms.

We report on the direct femtosecond laser ablation of sub-λ/4 (80–250 nm) holes in LiNbO3 crystals and on its local near-field imaging. We show that the near-field transmission of holes can feature an attenuation of ∼75% at hole central position, and a ∼20% transmission enhancement at its sides. This high-contrast ring-shaped near-field distribution is found to be in agreement with simulations, suggesting the surface relief as the main contrast mechanism.

A study of Ba(2)NaNb(5)O(15) and LiNbO(3) crystals with periodic ferroelectric domain structures using the scanning near field optical microscopy technique is reported. Optical contrast is observed in the regions of ferroelectric domain boundaries and it is analysed using beam propagation method modelling. This reveals that the optical contrast, a consequence of changes in the refractive index, is not due to variation of the waveguide-coupling efficiency, and supports the hypothesis that it is associated with the domain array, which is related to the size of the domain.

Multilayers of MgF2 and Sb2S3 have been obtained by physical vapour deposition on glass substrates. Changes in the optical and structural properties have been studied as a function of annealing temperature and the number of layers. A drastic variation in optical transmission, microstrain and grain size is observed at a temperature near 225??C. A comparison of the material properties of multilayers and a monolayer is carried out.

We report on the in-depth micro-modifications induced by femtosecond laser ablation in Nd:YAG crystals. Near Field Optical experiments have revealed that, below the ablated volume, a permanent change in the Nd:YAG reflectivity, extending parallel to the irradiation direction, has been induced. Micro-luminescence experiments have provided experimental evidence that these permanent changes in the surface reflectivity are accompanied by strong changes in the luminescence properties of Nd(3+) ions revealing relevant micro structural modifications in the Nd:YAG system.

In the present work, aperiodically poled lithium niobate (APPLN) was grown, along the a-axis, by the off-centred Czochraski method. The domain formation has been triggered by rare earth doping, using in this case Er3+ and Yb3+ ions. The growth conditions were selected in order to obtain a modulated domain distribution. SNOM measurements have been performed with a Nanonics Imaging Ltd model MultiView 200 TM working in non-contact tapping mode.