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
4 results
Search Results
Now showing 1 - 4 of 4
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 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 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 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.