Person: Weigand Talavera, Rosa María
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First Name
Rosa María
Last Name
Weigand Talavera
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Óptica
Area
Optica
Identifiers
12 results
Search Results
Now showing 1 - 10 of 12
Item On the generality of measuring ultrabroad-band ultrashort laser pulses with the d-scan technique using ensembles of dielectric nano- and microparticles(Optics and Laser Technology, 2024) Pérez Benito, Óscar; Cabrera Granado, Eduardo; García Martín, Susana; García González, Ester; Weigand Talavera, Rosa MaríaWe 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.Item Dispersion-scan measurements of few-cycle pulses compressed with the multiplate continuum process(2017 Conference On Lasers and Electro-Optics Europe & European Quantum Electronics Conference (Cleo/Europe-Eqec), 2017) Canhota, Miguel; Weigand Talavera, Rosa María; Crespo, Helder M.Item Full temporal characterization of ultrabroadband few-cycle laser pulses using atomically thin WS_2(ACS Photonics, 2023) Pérez Benito, Óscar; Hernández Rueda, Francisco Javier; Martínez Maestro, Laura; Noordam, Marc L.; Kuipers, L.; Weigand Talavera, Rosa MaríaNowadays, 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).Item Powerful algebraic model to design Q-switched lasers using saturable absorbers(Optics and laser technology, 2023) Pérez Alonso, Vanesa; Weigand Talavera, Rosa María; Sánchez Balmaseda, Margarita María; Guerra Pérez, José ManuelUsing 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.Item On the Q-switched operation of Titanium: sapphire lasers using a graphene-based saturable absorber mirror(Optics and laser technology, 2015) Weigand Talavera, Rosa María; Pinto, T.; Crespo, H. M.; Guerra, J. M.We numerically demonstrate Q-switched operation of Titanium:Sapphire lasers using mono and multilayer graphene, deposited on a totally reflecting end mirror as a saturable absorber. Output energies, pulse duration and repetition frequencies of the Q-switched pulse trains are given as a function of the pump intensity for different number of graphene layers and cavity lengths. For the geometries studied, pulses from 17 to 491 ns can be achieved, with energies ranging from 11 to 74 μJ and repetition rates from 0.06 to 2.5 MHz. These results can be useful for designing and building laser cavities for Q-switched and mode-locked operation in laser media with short lifetimes as Titanium:Sapphire.Item Optical transmission properties of Pentelic and Paros marble(Applied optics, 2015) Weigand Talavera, Rosa María; García, Pablo A.; Campos Acosta, Joaquín; Storch de Gracía, JacoboAncientGreek 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.Item In-situ temporal characterization of chirped ultra-broadband laser pulses exciting a dual-light emitter Er3+-doped perovskite(Photonics, 2023) Pérez Benito, Óscar; Weigand Talavera, Rosa MaríaWe 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.Item Inline self-diffraction dispersion-scan of over octave-spanning pulses in the single-cycle regime(Optics letters, 2017) Canhota, Miguel; Silva, Francisco; Weigand Talavera, Rosa María; Crespo, Helder M.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.Item Q-switched operation with carbon-based saturable absorbers in a Nd:YLF Laser(Applied sciences, 2015) Weigand Talavera, Rosa María; Sánchez Balmaseda, Margarita María; Guerra Pérez, José ManuelWe 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.Item Chirp-dependent dual light emission in Na_(0.95)Er_(0.05)Nb_(0.9)Ti_(0.1)O_(3) perovskite(Optical materials, 2022) Pérez Benito, Óscar; Antón Revilla, Miguel Ángel; Urones Garrote, Esteban; García Martín, Susana; García González, Ester; Weigand Talavera, Rosa MaríaPolar 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.