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El proyecto se enfoca en la mejora de la calidad de la enseñanza práctica en la asignatura Coherencia Óptica y Láser del cuarto curso del Grado en Física y en la asignatura obligatoria Instrumentación Biomédica del Máster en Física Biomédica. Para ello se han desarrollado prácticas avanzadas en el área de Óptica, modernizado los contenidos de prácticas ya existentes y actualizado los métodos de evaluación de los resultados de aprendizaje del estudiante.

We take advantage of the dual emission properties of up-conversion fluorescence (UCF) and second harmonic generation (SHG) in Er3+-doped perovskite Na0.95Er0.05Nb0.9Ti0.1O3 to fully temporally characterize the ultrashort laser pulse that excites Er3+-ion fluorescence. The chirped pulses from a broadband Ti:Sa oscillator are temporally characterized using the dispersion scan (d-scan) technique by using the SHG signal in the host perovskite at the same point where UCF is being produced by the same pulse. The pulse durations obtained range from similar to 45 fs to similar to 8 fs and positive and negative spectral phases are unambiguously identified. The temporal characterization is compared using a standard non-linear crystal and perfect agreement is obtained. These results show that it is possible to temporally characterize in-situ ultrashort laser pulses while they are inducing a UCF process, as long as the host generates second-harmonic signal., Ministerio de Economia y Competitividad (España), Universidad Complutense de Madrid, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

©2023 By the author(s) Licensee MDPI This research was funded by the Ministerio de Ciencia e Innovación (MCINN), grant number PID2021-123112OB-C21, and Comunidad Autónoma de Madrid by S2018/NMT-4321 NANOMAGCOST. The authors also acknowledge the Sistema Nacional de Garantía Juvenil through the Comunidad Autónoma de Madrid for providing a pre-doctoral contract, PEJ-2020-AI/IND-17711., A systematic study on laser-induced heating carried out in two biological windows (800 nm and 1053 nm) for Fe_(3)O_(4) nanoparticles in water suspension showed evidence of the strong dependence of the specific absorption rate (SAR) on extrinsic parameters such as the vessel volume or laser spot size. The results show that a minimum of 100 mu L must be used in order to obtain vessel-size-independent SARs. In addition, at a constant intensity but different laser powers and spot size ratios, the SARs can differ by a three-fold factor, showing that the laser power and irradiated area strongly affect the heating curves for both wavelengths. The infrared molecular absorber IRA 980B was characterized under the same experimental conditions, and the results confirm the universality of the SARs' dependence on these extrinsic parameters. Based on these results, we propose using solutions of IRA 980B as a standard probe for SAR measurements and employing the ratio SAR(iron oxide)/SAR(IRA 980B) to compare different measurements performed in different laboratories. This measurement standardization allows us to extract more accurate information about the heating performance of different nanoparticles., Ministerio de Ciencia e Innovación (MICINN), Comunidad de Madrid, Depto. de Física de Materiales, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

2023 Acuerdos transformativos CRUE, Using the rate equations and their stability analysis, an algebraic model has been developed to predict the values of characteristic magnitudes of the output of a laser operating in passive Q-switched regime, such as peak power, temporal pulse width, pulse energy and pulse period. The results are compared with the numerical integrations of the equations, and an excellent agreement in a vast range of values of the laser parameters (gain, saturable absorption, linear losses, cavity round-trip and saturation energies and lifetimes of laser medium and absorber) has been obtained. The model is very useful to design this type of lasers in an agile way, without the need of integration of the corresponding rate equations., Comunidad Autónoma de Madrid, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

2023 Acuerdos transformativos CRUE, Nowadays, the accurateand full temporal characterization of ultrabroadbandfew-cycle laser pulses withpulse durations below 7 fs is of great importance in fields of sciencethat investigate ultrafast dynamic processes. There are several indirectmethods that use nonlinear optical signals to retrieve the complexelectric field of femtosecond lasers. However, the precise characterizationof few-cycle femtosecond laser sources with an ultrabroadband spectrumpresents additional difficulties, such as reabsorption of nonlinearsignals, partial phase matching, and spatiotemporal mismatches. Inthis work, we combine the dispersion scan (d-scan) method with atomicallythin WS2 flakes to overcome these difficulties and fullycharacterize ultrabroadband laser pulses with a pulse duration of6.9 fs and a spectrum that ranges from 650 to 1050 nm. Two-dimensionalWS(2) acts as a remarkably efficient nonlinear medium thatoffers a broad transparency range and allows for achieving relaxedphase-matching conditions due to its atomic thickness. Using mono-and trilayers of WS2, we acquire d-scan traces by measuringthe second-harmonic generation (SHG) signal, originated via laser-WS2 interaction, as a function of optical dispersion (i.e., glassthickness) and wavelength. Our retrieval algorithm extracts a pulseduration at full-width half-maximum of 6.9 fs and the same spectralphase function irrespective of the number of layers. We benchmarkand validate our results obtained using WS2 by comparingthem with those obtained using a 10-mu m-thick BBO crystal. Ourfindings show that atomically thin media can be an interesting alternativeto micrometer-thick bulk crystals to characterize ultrabroadband femtosecondlaser pulses using SHG-d-scan with an error below 100 as (attoseconds)., Ministerio de Economía y Competitividad (España), Agencia Española de Investigación, Universidad Complutense de Madrid, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2010 Optical Society of America. We thank Fransisco del Monte for valuable advice and CAI-UCM facilities. The financial support from the Spanish Ministry of Science and Innovation under projects TEC 2008-04105, CTQ2008-02578/BQU and Consolider SAUUL CSD2007-00013 is acknowledged. M. P. H.-G. and P. V. acknowledge the Spanish Ministry of Foreign Affairs and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Brazil) for financial support, respectively., We present an approach to generate paraxial laser beams with arbitrary spatial distribution in the femtosecond time regime. The proposed technique is based upon a pair of volume phase holographic gratings working in parallel arrangement. It exploits the spatial coherence properties of the incoming laser beam in a compact and robust setup that mitigates angular and spatial chirp. The gratings were recorded in a photopolymerizable glass with a high optical damage threshold and a large optical throughput. Setup performance is studied and experimentally demonstrated by generating Laguerre-Gaussian femtosecond pulses., Ministerio de Ciencia e Innovación (MICINN), España, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Brazil), Ministerio de Asuntos Exteriores y de Cooperación, España, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2015 by the authors; licensee MDPI, Basel, Switzerland. This work has been financed by the Universidad Complutense de Madrid through Project GR3/14-910133., We have numerically studied the influence of the absorption modulation depth of carbon-based saturable absorbers (graphene and carbon nanotubes (CNTs)) on the Q-switched regime of a diode-pumped Nd:YLF laser. A short-length cavity was used with an end mirror on which CNTs or mono- or bi-layer graphene were deposited, forming a saturable absorber mirror (SAM). Using a standard model, the generated energy per pulse was calculated, as well as the pulse duration and repetition rate. The results show that absorbers with higher modulation depths, i.e., graphene, deliver higher energy pulses at lower repetition rates. However, the pulse duration did not have a monotonic behavior and reaches a minimum for a given low value of the modulation depth typical of CNTs., Universidad Complutense de Madrid (UCM), Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2015 Optical Society of America, AncientGreek and Roman sources report that the statue of Zeus in Olympia had a head, and in particular eyes, similar to the description of Zeus by Homer, so we think that the statue was visible to the human eye. Since the temple was 12mhigh, and had a small door and no windows, the illumination of the statue by conventionalmedia is questionable. The aimof this paper is to characterize the optical transmission of Paros and Pentelic marble to demonstrate that it was possible to have the Zeus temple illuminated through the roof marble tiles. Spectral absolute transmittance measurements were taken in samples with different thicknesses using a calibrated spectrophotometer, as well as total transmittance measurements using a luxmeter. The results show that both types of marble transmit light and that Pentelic marble has a higher transmittance in the visible range than Paros marble in some cases and hence could have been one reason, among others, to change the type of marble in the roof in antiquity., Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2022 Elsevier B.V. E. García-González and S. García-Martín thank MICINN/AEI for funding the project PID2019-106662RB-C44/ AEI /10.13039/501100011033 and R.Weigand thanks MINECO/AEI for funding the project FIS2017-87360-P. O. Pérez-Benito acknowledges a predoctoral contract from UCM (call CT63/19-CT64/19). We acknowledge the help of O. Contreras in the development of the synthesis experiments. We will always be indebted to Professor E. Morán for the knowledge transmitted, he left us too early, untimely., Polar Na_(0.95)Er_(0.05)Nb_(0.9)Ti_(0.1)O_(3) perovskite has been synthesized as a nanostructured material by microwave assisted hydrothermal method. The characterization indicates that erbium is a constituent of the crystal structure and is preferentially located in sodium positions. The compound combines the nonlinear optical properties of the host (NaNb_(0.9)Ti_(0.1)O_(2.95) and the fluorescent properties of the Er^(3+)-dopant. Under excitation by a single femtosecond (< 10 fs) laser in the near-infrared region, simultaneous dual emission signals of second harmonic generation (SHG) and up-converting fluorescence (UCF) are observed and the nonlinear dependencies of the SHG and UCF intensities on the excitation intensity are measured. In addition, both emissions are shown to be sensitive to the chirp of the exciting pulses, and for UCF, it can be explained by means of a simple theoretical model based on the density matrix equations. These nano-structured particles with chirp-dependent dual behavior can be very advantageous when used in biological systems, since they can provide complementary information in different spectral ranges and tissues and are susceptible of coherent control, which can be both useful in optical microscopy and bioimaging., Ministerio de Ciencia e Innovación (MICINN)/AEI, Ministerio de Economía y Competitivdad (MINECO)/AEI, Universidad Complutense de Madrid, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2017 Optical Society of America. Funding: Fundacao para a Ciencia e a Tecnologia (FCT) [UID/NAN/50024/2013]; Ministerio de Economia y Competitividad (MINECO) [FIS2013-41709P], We present an implementation of dispersion-scan based on self-diffraction (SD d-scan) and apply it to the measurement of over octave-spanning sub-4-fs pulses. The results are compared with second-harmonic generation (SHG) d-scan. The efficiency of the SD process is derived theoretically and compared with the spectral response retrieved by the d-scan algorithm. The new SD d-scan has a robust inline setup and enables measuring pulses with over-octave spectra, single-cycle durations, and wavelength ranges beyond those of SHG crystals, such as the ultraviolet and the deep-ultraviolet. (C) 2017 Optical Society of America., Ministerio de Economía y Competitividad (MINECO), Fundacao para a Ciencia e a Tecnologia (FCT), Portugal, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

Se generaran topografías FDTD en sistemas fotónicos para ejemplificación en clase por parte del profesor, realización de trabajos en grupo, realización de prácticas de laboratorio, autoaprendizaje del alumno y Trabajos Fin de Grado y Máster.

Se generaran topografías FDTD en sistemas fotónicos para ejemplificación en clase por parte del profesor, realización de trabajos en grupo, realización de prácticas de laboratorio, autoaprendizaje del alumno y Trabajos Fin de Grado y Máster.

By crossing two intense ultrashort laser pulses with different colors in a transparent medium, like a simple piece of glass, a fan of multicolored broadband light pulses can be simultaneously generated. These newly generated pulses are emitted in several well-defined directions and can cover a broad spectral range, from the infrared to the ultraviolet and beyond. This beautiful phenomenon, first observed and described 15 years ago, is due to highly-nondegenerate cascaded four-wave mixing (cascaded FWM, or CFWM). Here, we present a review of our work on the generation and measurement of multicolored light pulses based on third-order nonlinearities in transparent solids, from the discovery and first demonstration of highly-nondegenerate CFWM, to the coherent synthesis of single-cycle pulses by superposition of the multicolored light pulses produced by CFWM. We will also present the development and main results of a dedicated 2.5-D nonlinear propagation model, i.e., with propagation occurring along a two-dimensional plane while assuming cylindrically symmetric pump beam profiles, capable of adequately describing noncollinear FWM and CFWM processes. A new method for the generation of femtosecond pulses in the deep-ultraviolet (DUV) based on FWM and CFWM will also be described. These experimental and theoretical results show that highly-nondegenerate third-order nonlinear optical processes are formally well understood and provide broader bandwidths than other nonlinear optical processes for the generation of ultrashort light pulses with wavelengths extending from the near-infrared to the deep-ultraviolet, which have many applications in science and technology., COMPETE/FEDER, Fundação para a Ciência e Tecnologia (FCT), Universidad Complutense de Madrid, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

Recibido / Received: 30/10/2010. Aceptado / Accepted: 15/12/2010, En este trabajo presentamos las líneas de investigación del Grupo de Física del Láser, Óptica Cuántica y Óptica No Lineal de la UCM. La investigación comprende trabajos experimentales y teóricos en el desarrollo de prototipos de láser, análisis de inestabilidades espacio-temporales en láseres de gran apertura, el estudio de propagación de radiación en régimen de luz lenta y de pulsos ultracortos en medios resonantes y no resonantes, la generación de radiación por procesos no lineales y el estudio de memorias ópticas por eco fotónico., We report on the main research lines carried out by our group. Our research comprises experimental and theoretical work in the development of laser prototypes, spatio-temporal instabilities in broadarea lasers, radiation propagation in the slow light regime and ultrashort pulse propagation in resonant and non-resonant media, radiation generation by non-linear processes and optical memories by photon-echo., Ministerio de Ciencia e Innovación de España (MICINN), Ministerio de Educación y Ciencia de España (MEC), Universidad Complutense de Madrid (España), Banco Santander Central Hispano (España), Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub

We demonstrate that temporal characterization of ultrabroadband laser pulses (∼ 7 fs) through the d-scan technique can be implemented using ensembles of SHG micro and/or nanocrystals independently of their crystal size and/or composition. The experimental results have been supported by numerical simulations based on the Finite-Difference-Time-Domain (FDTD) algorithm. Both, experiment and simulations show that, in spite of the low optical quality of the samples and the unavoidable appearance of incoherent light, the technique is robust and allows to measure ultrashort laser pulses using clusters of randomly distributed and piled-up polar micro- and nanocrystals., Ministerio de Economía, Comercio y Empresa (España), Ministerio de Ciencia, Innovación y Universidades (España), Universidad Complutense de Madrid, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, inpress