A high birefringence liquid crystal for lenses with large aperture.

This work presents the application of an experimental nematic liquid crystal (LC) mixture (1929) in a large aperture lens. The LC material is composed of terphenyl and biphenyl derivatives compounds with an isothiocyanate terminal group and fluorinated lateral substituents. The substitution with a strongly polar isothiocyanate group and an aromatic rigid core provides [Formula: see text]-electron coupling, providing high birefringence ([Formula: see text] at 636 nm and 23 °C) and low viscosity ([Formula: see text] = 17.03 mPa s). In addition, it also shows high values of birefringence at near infrared (0.318 at 1550 nm). The synthesis process is simple when comparing materials with high melting temperatures. The excellent properties of this LC mixture are demonstrated in a large aperture LC-tunable lens based on a transmission electrode structure. Thanks to the particular characteristics of this mixture, the optical power is high. The high birefringence makes this LC of specific interest for lenses and optical phase modulators and devices, both in the visible and infrared regions.

Aspherical liquid crystal lenses based on a variable transmission electrode.

In this work, a technique to generate aspherical liquid crystal lenses with positive and negative optical power is experimentally demonstrated. The main enabling element is a micro-metric electrode with variable spatial size. This produces a decreasing resistance towards the lens centre that generates the desired voltage/phase profiles. Then, the voltage is homogeneously distributed across the active area of the lens by micro-metric concentric electrodes. As it is demonstrated, the phase shift can be controlled with voltages from 0 to 4.5 VRMS. As a result, parabolic profiles are obtained both for negative and positive optical powers. Furthermore, this approach avoids some disadvantages of previous techniques; parabolic profiles can be obtained with only one lithographic step and one or two voltage sources. Other complex aspherical profiles could be fabricated using the same technique, such as elliptical or hyperbolic ones.

Analogue of electromagnetically induced transparency in square slotted silicon metasurfaces supporting bound states in the continuum.

In this work, a silicon metasurface designed to support electromagnetically induced transparency (EIT) based on quasi-bound states in the continuum (qBIC) is proposed and theoretically demonstrated in the near-infrared spectrum. The metasurface consists of a periodic array of square slot rings etched in a silicon layer. The interruption of the slot rings by a silicon bridge breaks the symmetry of the structure producing qBIC stemming from symmetry-protected states, as rigorously demonstrated by a group theory analysis. One of the qBIC is found to behave as a resonance-trapped mode in the perturbed metasurface, which obtains very high quality factor values at certain dimensions of the silicon bridge. Thanks to the interaction of the sharp qBIC resonances with a broadband bright background mode, sharp high-transmittance peaks are observed within a low-transmittance spectral window, thus producing a photonic analogue of EIT. Moreover, the resonator possesses a simple bulk geometry with channels that facilitate the use in biosensing. The sensitivity of the resonant qBIC on the refractive index of the surrounding material is calculated in the context of refractometric sensing. The sharp EIT-effect of the proposed metasurface, along with the associated strong energy confinement may find direct use in emerging applications based on strong light-matter interactions, such as non-linear devices, lasing, biological sensors, optical trapping, and optical communications.

Strongly resonant silicon slot metasurfaces with symmetry-protected bound states in the continuum.

In this work, a novel all-dielectric metasurface made of arrayed circular slots etched in a silicon layer is proposed and theoretically investigated. The structure is designed to support both Mie-type multipolar resonances and symmetry-protected bound states in the continuum (BIC). Specifically, the metasurface consists of interrupted circular slots, following the paradigm of complementary split-ring resonators. This configuration allows both silicon-on-glass and free-standing metasurfaces and the arc length of the split-rings provides an extra tuning parameter. The nature of both BIC and non-BIC resonances supported by the metasurface is investigated by employing the Cartesian multipole decomposition technique. Thanks to the non-radiating nature of the quasi-BIC resonance, extremely high Q-factor responses are calculated, both by fitting the simulated transmittance spectra to an extended Fano model and by an eigenfrequency analysis. Furthermore, the effect of optical losses in silicon on quenching the achievable Q-factor values is discussed. The metasurface features a simple bulk geometry and sub-wavelength dimensions. This novel device, its high Q-factors, and strong energy confinement open new avenues of research on light-matter interactions in view of new applications in non-linear devices, biological sensors, and optical communications.

Multifunctional light beam control device by stimuli-responsive liquid crystal micro-grating structures.

There is an increasing need to control light phase with tailored precision via simple means in both fundamental science and industry. One of the best candidates to achieve this goal are electro-optical materials. In this work, a novel technique to modulate the spatial phase profile of a propagating light beam by means of liquid crystals (LC), electro-optically addressed by indium-tin oxide (ITO) grating microstructures, is proposed and experimentally demonstrated. A planar LC cell is assembled between two perpendicularly placed ITO gratings based on microstructured electrodes. By properly selecting only four voltage sources, we modulate the LC-induced phase profile such that non-diffractive Bessel beams, laser stretching, beam steering, and 2D tunable diffraction gratings are generated. In such a way, the proposed LC-tunable component performs as an all-in-one device with unprecedented characteristics and multiple functionalities. The operation voltages are very low and the aperture is large. Moreover, the device operates with a very simple voltage control scheme and it is lightweight and compact. Apart from the demonstrated functionalities, the proposed technique could open further venues of research in optical phase spatial modulation formats based on electro-optical materials.

Positive-negative tunable liquid crystal lenses based on a microstructured transmission line.

In this work, a novel technique to create positive-negative tunable liquid crystal lenses is proposed and experimentally demonstrated. This structure is based on two main elements, a transmission line acting as a voltage divider and concentric electrodes that distribute the voltage homogeneously across the active area. This proposal avoids all disadvantages of previous techniques, involving much simpler fabrication process (a single lithographic step) and voltage control (one or two sources). In addition, low voltage signals are required. Lenses with switchable positive and negative focal lengths and a simple, low voltage control are demonstrated. Moreover, by using this technique other optical devices could be engineered, e.g. axicons, Powell lenses, cylindrical lenses, Fresnel lenses, beam steerers, optical vortex generators, etc. For this reason, the proposed technique could open new venues of research in optical phase modulation based on liquid crystal materials.

Ultrahigh-quality factor resonant dielectric metasurfaces based on hollow nanocuboids.

In this work, a dielectric metasurface consisting of hollow dielectric nanocuboids, with ultrahigh quality factor, is theoretically proposed and demonstrated. The variation of the hole size of the cuboid allows for the tuning of the resonant anapole mode in the nanoparticles. The metasurface is designed to operate in two complementary modes, namely electromagnetically induced transparency and narrowband selective reflection. Thanks to the non-radiative nature of the anapole resonances, the minimal absorption losses of the dielectric materials, and the near-field coupling among the metasurface nanoparticles, a very high quality factor of Q=2.5×106 is achieved. The resonators are characterized by a simple bulk geometry and the subwavelength dimensions of the metasurface permit operation in the non-diffractive regime. The high quality factors and strong energy confinement of the proposed devices open new avenues of research on light-matter interactions, which may find direct applications, e.g., in non-linear devices, biological sensors, laser cavities, and optical communications.

Tunable liquid crystal cylindrical micro-optical array for aberration compensation.

A tunable aberration compensation device for rectangular micro-optical systems is proposed and demonstrated. This device, which is based in nematic liquid crystal and a micro-electrode structure, forms gradients in the index of refraction as a function of voltage. We have developed a fringe skeletonizing application in order to extract the 3D wavefront from an interference pattern. This software tool obtains the optical aberrations using Chebyshev polynomials. By using phase shifted electrical signals the aberrations can be controlled independently. A complete independent control over the spherical and coma aberration has been demonstrated. Also, an independent control over the astigmatism aberration has been demonstrated in a broad range. This device has promising applications where aberration compensation is required. The independent compensation achieved for some coefficients, such as astigmatism for example, is more than 2.4 waves.

Note: Electrical modeling and characterization of voltage gradient in liquid crystal microlenses.

In this work, a novel equivalent electric circuit for modeling liquid crystal microlenses is proposed. This model is focused on explaining a lens behavior at the micrometric scale, using its manufacturing parameters. It suggests an approach to predict the solution of the voltage gradient distribution across a microlens. An interesting feature of the model is that it provides an analytical solution for microlenses with modal and hole-patterned electrode schemes, by a simple software tool. The model flexibility allows lens designers to apply complex waveform signals with different harmonics. The voltage distribution has been tested. The simulated and measured voltage profiles are fairly in agreement.

Note: tunable notch filter based on liquid crystal technology for microwave applications.

In this work, a compact design of an electrically tunable notch filter, based on liquid crystal (LC) technology, has been designed, manufactured, and characterized. The proposal has been achieved through particular configuration schemes with low cost inverted-microstrip structures and conventional spurlines structures due to its ease of integration. Central frequency tunability has been induced by applying low ac voltages, thus involving low power consumption. For these devices, filter responses have been approached specifically at microwave C-band frequency allocated for many satellite communications applications. Also, it has taken advantage of new highly anisotropic nematic LC mixtures at those frequency ranges.

Eficacia de la terapia de grupo en pacientes alcohólicos tras dos años de seguimiento / No disponible

Introducción: Actualmente, la terapia de grupo (TG)está considerada como una herramienta primordial para eltratamiento del alcoholismo. La identificación que hace elalcohólico con los otros integrantes del grupo, que padecenproblemas semejantes, le refuerza de forma positivatanto en lo emocional como en lo cognitivo. El propósitode la TG es la abstinencia de alcohol, y sólo será posiblesu consecución si el enfermo logra adquirir conciencia deenfermedad, más fácil de asumir ante la presencia de otraspersonas que se reconocen alcohólicos.Metodología: Se seleccionaron los 200 primerospacientes incluidos en el Programa de Alcoholismo de unServicio de Salud Mental, con el diagnóstico de dependenciade alcohol según la clasificación diagnóstica DSMIV-TR y con la tipología de alcoholómano o gamma,acorde a la clasificación de tipos de alcoholismo de Alonso-Fernández o Jellinek respectivamente. De estos, el60% acudía a TG y el 40% no. Durante 2 años se hizo unseguimiento de cada uno de estos pacientes, registrando sise encontraba en abstinencia, recaída o abandono.Resultados y conclusiones: No se han encontradodiferencias significativas en las características sociodemográficas,salvo en la edad, en las dos poblaciones dela muestra, los que acudían a TG y los que no. Lospacientes alcohólicos que asistían a TG obtienen tasasde abstinencia a lo largo de los 24 meses de seguimientosignificativamente superiores a los que no iban. A los2 años, el 52% de los pacientes que realizaban TG estabanen abstinencia frente al 19 de los que no. Por otrolado, los que acudían a la TG tienen, de forma estadísticamentesignificativa, tasas de abandono menores, encualquiera de los períodos del seguimiento en los 24meses. Al cabo de los 2 años abandonan un 35% de losque asistían a TG frente al 78% de los que no. La adherenciaal tratamiento de los que van a TG es del 64%(AU)

Introduction: Nowadays, group therapy (GT) is consideredan essential tool in alcoholism treatment. Theidentification of the alcoholic patient with the rest ofparticipants of the group, who suffer from similar problems,reinforce him positively in both emotional andcognitive. The purpose of group therapy is alcoholabstinence what will be only possible by become awareof alcoholism, easier to assume in front of others whorecognized themselves as alcoholic.Methods: There were selected the first 200 patientsenrolled in the alcoholism program of a Mental HealthService who met criteria for “Ethylic Dependence Syndrome”following DSM-IV-TR criteria and also consideredalcoholómano or gamma type following AlonsoFernández’s or Jellinek types of alcoholism: 60%shown up to group therapy. We made a two-year followup, recording whether they were in abstinence, relapseor if they had abandoned.Results and conclusions: There were not statisticaldifferences in sociodemographic characteristics, exceptage, between both groups therapy-group attendants andnon-therapy-group patients. After 24 months of followup, alcoholic patients who attended GT obtained ratesof abstinence significatively superior to those who donot attended. 52% of patients in group therapy were inabstinence comparing with 19% of those who were not.Abandone rates were signiticatively less in patients inGT, in both periods of the 24 moths of follow up, 78%patients in non-GT abandoned treatment in comparisonwith 35% of patients in GT, 64% of treatment adherencein GT patients(AU)

Seguimiento de pacientes alcohólicos tras 2 años de tratamiento / Follow-up of alcoholic patients after 2 years treatment

Introducción: Uno de los objetivos del seguimientodel paciente alcohólico es saber si este se halla en abstinencia,recaída o en abandono del tratamiento. El logrode la abstinencia y su mantenimiento mejora los problemasfísicos, psíquicos y sociales relacionados con el alcohol.Para conseguirlo es muy beneficioso que el pacienteesté incluido en un programa de alcoholismo apropiado,donde pueda tener el apoyo preciso para resolver lascomplicaciones que surjan durante su tratamiento.Metodología: El trabajo se realizó en el Servicio deSalud Mental “Puente de Vallecas”, Madrid. Se seleccionaronlos 300 primeros pacientes con los diagnósticosde “síndrome de dependencia etílica” y “abuso dealcohol” según la clasificación diagnóstica DSM-IV-TRy que estaban incluidos en el Programa de Alcoholismode este centro.Resultados y conclusiones: El 89,67% de la muestrason varones y el 10,33% son mujeres. Al estudiar la evoluciónde los pacientes durante el tratamiento se obtieneque el 39,67% de la muestra estudiada se encuentra enabstinencia, que las recaídas aumentan hasta el sexto mesy que los mayores porcentajes de abandono se producenhasta el noveno, hasta llegar al 51% a los dos años de tratamiento

Introduction: One of the targets of the follow up ofalcoholic patients is to assess abstinence, relapse, ortreatment give up. The achievement and maintenance ofabstinence, improve physical, psychical and socialdimension of alcohol-related problems. For this it isbeneficial for patients to be enrolled in a suitable Programmefor Alcoholism, where support for complicationsalongside the treatment can be dealt with.Methodology: 300 patients were selected with thediagnostic “alcohol dependency syndrome” and “alcoholabuse” according to the DSM-IV-TR, from theAlcoholism Programme of the mental health centre. Thefollow up was done in the months 1-3-6-9-12-15-18-21and 24, recording the clinical situation (abstinence,relapse or abandon).Results and conclusions: After two years of developmentof the Alcoholism Programme, 39.67% keepabstinence, 9.33% relapsed, and 51% have abandoned.Treatment adherence (two first categories) is 49% in 24months. In the sixth month, abstinence stabilizes, aswell as relapses have a peak. Abandons rise progressivelyup to the 9th month (AU)

Relación entre juego patológico y tipo de alcoholismo / Relationship between pathological gambling and types of alcoholism

Introducción: La teoría etiopatogénica más aceptadaes la que relaciona el juego patológico con una adicción,sin tóxico, caracterizada por una pérdida paulatina en elcontrol del impulso a jugar. Si el juego patológico es undescontrol de los impulsos, estaría más asociado a lostipos de alcoholismo donde hay una mayor impulsión abeber y, por tanto, pérdida de control. Este estudio analizaen qué tipo de alcoholismo de la clasificación deAlonso-Fernández es más frecuente el juego patológico.Metodología: En nuestro trabajo se estudia a todoslos pacientes atendidos en el programa de alcoholismodel Servicio de Salud Mental de Puente de Vallecas(Madrid) entre los años 1997 y 2003. Estos son 547 pacientesdiagnosticados según el DSM-IV-TR de “síndromede dependencia etílica” y “abuso de alcohol”. De ellosse encontraron 86 pacientes que cumplían criterios dejuego patológico, según DSM-IV-TR. Los pacientes seclasificaron según la tipología de Alonso-Fernández yse estudió su distribución según padecieran o no ludopatía.Resultados: El 32,58% de los alcohólicos ludópatases bebedor enfermo psíquico, significativamente mayorque el 14,32% de alcohólicos no ludópatas de este mismotipo de alcoholismo. El porcentaje de alcoholómanosen los alcohólicos no jugadores (67,03 %) es mayorque en los alcohólicos jugadores (53,49%). Igualmentela proporción de bebedores excesivos regulares entrelos alcohólicos no jugadores (18,66%) es algo mayorque en los alcohólicos jugadores (13,95%).Conclusiones: Los alcohólicos afectados de juegopatológico tienen una mayor probabilidad de ser bebedoresenfermos psíquicos, enfermedad en la que una desus características es la impulsividad, que los alcohólicossin ludopatía

Introduction: The progressive loose of impulses control is the most acceptable theory that correlates pathological gambling with addiction, without toxic substance. If pathological gambling is due to this loose of control, the type of alcoholism related with gambling would be impulsive drinking. The aim of this study is to analyse the type of alcoholism following Alonso Fernández’s classification is associated with pathological gambling. Methods: In this paper we study a population of 547 patients enrolled in the alcoholism program of the Mental Health Service of Puente de Vallecas (Madrid) between 1997 and 2003. All patients met the criteria for “ethylic dependence syndrome” and “alcohol abuse” following DSM-IV-TR criteria. From this population of 547 patients, 86 also met the criteria for pathological gambling defined by DSM-IV-TR criteria. Patients were classified following Alonso Fenández’s types of alcoholism. And we study the distribution of these types of alcoholism due to the presence or absence of pathological gambling. Results: Our results show that 32.58% of alcoholic gambles are mental patient drinkers. This data is significantly bigger compare to the 14.2% of the non-gamblers alcoholics with the same type of alcoholism. The percentage of alcohol addicts in alcoholics non-gamblers (67.03%) is bigger than in alcoholic patients with pathological gambling (53.94). Likewise, the rate of excessive regular drinkers between non-gamblers alcoholics (18.66%) is slightly bigger than alcoholic gamblers (13.95%). Conclusions: Alcoholic patients with pathological gambling are more likely to be drinker psychiatry patients than alcoholic patients without pathological gambling because loose of control is the main characteristic in alcoholic patients with pathological gambling

Juego patológico asociado a alcoholismo: un estudio de comorbilidad / Pathological gambling related to alcoholism: a comorbidity study

Introducción: El juego patológico se caracteriza por un déficit progresivo en el control del impulso a jugar. Se considera que la prevalencia del juego patológico en la población general fluctúa entre el 0,5 y el 2,5%. Diversos estudios han demostrado la comorbilidad del juego patológico en el alcoholismo. Metodología: En nuestro trabajo se estudia a todos los pacientes atendidos en el programa de Alcoholismo del Servicio de Salud Mental de Puente de Vallecas (Madrid) entre los años 1997 y 2003. Estos son 547 pacientes diagnosticados según el DSM-IV-TR de "síndrome de dependencia etílica" y "abuso de alcohol". De ellos se revisaron todas las historias clínicas para detectar todos los pacientes que cumplían criterios de juego patológico, según DSM-IV-TR. Resultados y Conclusiones: Se encuentra que el 15,72% (n = 86) de los pacientes con problemas de alcohol padece un trastorno por juego patológico. Se hace un análisis comparativo entre las dos muestras de pacientes con problemas de alcohol, jugadores y no jugadores, y se obtiene que los varones alcohólicos tienen un riesgo significativamente mayor que las mujeres alcohólicas de padecer ludopatía. El 62,8% de los jugadores tiene el descontrol del juego "dependiente" del consumo de alcohol. En nuestra población, el 83,7% de los alcohólicos jugadores son adictos a las máquinas "tragaperras". Por tanto, siempre hay que indagar en un alcohólico si tiene problemas con el juego y en un ludópata si 10 tiene con el alcohol

lntroduction: The pathological gambling is characterized by a progressive deficit in fue control of fue impulsive to gamble. It is estimated that fue prevalence of fue pathological gambling in fue general population is from 0.5 to 2.5%. Several studies have demonstrated pathological gambling as comorbidity of alcoholismo Methodology: In this papel are analysed all patients included in fue Programme of Alcoholism of fue Mental Healthcare Centre of fue district of Vallecas, Madrid, between 1997 and 2003, accounting for 547 patients classified within fue DSV-IV-TR as "ethylic dependency syndrome" and "alcohol abuse", searching their clinical records for pathological gambling (as defined algo by DSM-IV-TR). Results ana Conclusions: 15.72% (n = 86) of patients have pathological gambling comorbidity, being males at a higher risk than woman. In 62.8% of gamblers alcohol consumption cause pathological gambling. In OUT population 83.7% of alcoholic gamblers are addicts to slot machines. Finally it is always necessary to ask in the alcoholic people if they have problems with gambling and in the pathological gambling people if they have problems with fue alcohol

[Psychological profile of anesthesia residents in the province of Andalucia]. / Perfil psicológico de la población de médicos residentes de anestesiología en una provincia de Andalucía.

OBJECTIVES: To describe the personality traits and value systems of the population of residents in anesthesiology of a province in Andalusia and to analyze what the ideal profile of an anesthesiologist in training would be. SUBJECTS AND METHOD: Forty-four residents in anesthesiology were invited to participate, of whom 22 accepted. The participants voluntarily completed anonymous written questionnaires with 232 items: the sixteen personality factors questionnaire, form A (R.B. Cattell), and the survey of interpersonal values (L.V. Gordon). RESULTS: The residents scored high on primary factors of intelligence (B), self-sufficiency (Q2) and conservatism (Q1). High scores were also recorded on the secondary factors of anxiety (QI) and socialization (QIII); low scores were seen for independence (QIV). Four theoretical personality models (alpha, beta, gamma and delta) were established based on the data. Four residents were alphas (18%), 10 were betas (45%), 6 were gammas (27%) and 2 were deltas (10%). CONCLUSIONS: An ideal personal profile for residents in anesthesiology by American authors has been available since the 1960s. An ideal resident should be independent, calm, aware, stable, secure, self-disciplined and alert; moreover, he or she should enjoy team work. The residents with alpha personalities were ideal. At present, the training of residents and the selection criteria for access to specialized training based on a personality test are scarcely valued in our discipline.