Joan Josep Carvajal

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Stable and self-starting mode-locking of a Tm:KLu(WO(4))(2) crystal laser is demonstrated using a transmission-type single-walled carbon nanotube (SWCNT) based saturable absorber (SA). These experiments in the 2 microm regime utilize the E11 transition of the SWCNTs for nonlinear saturable absorption. The recovery time of the SWCNT-SA is measured by(More)
Porous GaN based LEDs produced by corrosion etching techniques demonstrated enhanced light extraction efficiency in the past. However, these fabrication techniques require further postgrown processing steps, which increases the price of the final system. Also, the penetration depth of these etching techniques is limited, and affects not only the(More)
We demonstrate continuous wave (CW) room temperature laser operation of the monoclinic Ho(3+)-doped KLu(WO(4))(2) crystal using a diode-pumped Tm(3+):KLu(WO(4))(2) laser for in-band pumping. The slope efficiency achieved amounts to ~55% with respect to the absorbed power and the maximum output power of 648 mW is generated at 2078 nm.
Buried channel waveguides were fabricated by liquid phase epitaxial growth of a lattice-matched KY(0.58)Gd(0.22)Lu(0.17)Tm(0.03)(WO4)2 film on a microstructured KY(WO4)2 substrate. Channels were transferred to the substrates by standard photolithography and Ar-ion milling. The bottom and sidewalls of the milled channels were smooth enough (rms roughness =(More)
KTiOPO(4) (KTP) nanocrystals have been synthesized by the modified Pechini method using ethylenediaminetetraacetic acid (EDTA) and ethylene glycol (EG) as chelating and sterification agents, respectively. Orthorhombic KTP has been obtained by calcination at 1073 K for several hours. Differential thermal and thermogravimetric (DTA-TG) analyses have been used(More)
A diode-pumped thin-disk laser based on Tm:KLu(WO4)2/KLu(WO4)2 epitaxies is realized. The emission is in the 1850-1945 nm spectral range for Tm-doping between 5 and 15 at. %. The maximum slope efficiency of 47% with respect to the absorbed power obtained with 5 at. % Tm:KLu(WO4)2/KLu(WO4)2 corresponds to a maximum output power of ~6 W in cw operation.
Non-contact thermometry is essential in biomedical studies requiring thermal sensing and imaging with high thermal and spatial resolutions. In this work, we report the potential use of Er:Yb:NaYF4 and Er:Yb:NaY2F5O up-conversion nanoparticles as thermal sensors by means of lifetime based luminescent thermometry. We demonstrate how Er:Yb:NaY2F5O nanocrystals(More)
We report the formation of two-dimensional disordered arrays of poly(methyl)methacrylate (PMMA) microcolumns with embedded single size distribution of Lu0.990Er0.520Yb0.490 nanocrystals, (Er,Yb):Lu2O3, using a disordered porous silicon template. The cubic (Er,Yb):Lu2O3 nanocrystals, which crystallize into the cubic system with Ia3¯ space group, were(More)
By means of micro-structural and optical characterization of the Yb:Nb:RbTiOPO(4) crystal, we demonstrated that the broad emission band of Yb(3+) in these crystals is due to the large splitting of the ytterbium ground state only, and not to a complex multisite occupation by the ytterbium ions in the crystals. We used this broad emission band to demonstrate(More)
We demonstrate a 60-fold enhancement of the second harmonic generation (SHG) response at the nanoscale in a hybrid metal-dielectric system. By using complex silver nanostructures photochemically deposited on the polar surface of a ferroelectric crystal, we tune the plasmonic resonances from the visible to the near-infrared (NIR) spectral region, matching(More)