Person:
Gómez Calderón, Óscar

First Name

Óscar

Last Name

Gómez Calderón

URI

https://hdl.handle.net/20.500.14352/79942

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Óptica y Optometría

Department

Óptica

Area

Optica

Identifiers

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Now showing 1 - 10 of 10

Líneas de investigación del Grupo UCM de Física del Láser, Óptica Cuántica y Óptica No Lineal
(Óptica Pura y Aplicada, 2011) Antón Revilla, Miguel Ángel; Arrieta Yáñez, Francisco; Cabrera Granado, Eduardo; Carreño Sánchez, Fernando; Ezquerro Rodríguez, José Miguel; Gómez Calderón, Óscar; Gonzalo Fonrodona, Isabel; Guerra Pérez, José Manuel; Melle Hernández, Sonia; Soler Rus, Miguel Odín; Sánchez Balmaseda, Margarita María; Weigand Talavera, Rosa María
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.
Dynamic population gratings in highly doped erbium fibers
(Journal of the Optical Society of America B, 2011) Melle Hernández, Sonia; Gómez Calderón, Óscar; Zhuo, Zhong C.; Antón Revilla, Miguel Ángel; Carreño Sánchez, Fernando
The efficiency of the dynamic population gratings recorded in highly doped erbium fibers has been studied. We find that the grating response increases with optical density, although the presence of erbium ion pairs in fibers with ion density of the order of 6:3 × 1025 m−3 degrades the grating efficiency. The experimental results have been reproduced including inhomogeneous upconversion processes in the nonlinear coupled-wave equations.
Homogeneous broadening effect on temperature dependence of green upconversion luminescence in erbium doped fibers
(Journal of Luminescence, 2013) Egatz-Gómez, Ana; Gómez Calderón, Óscar; Melle Hernández, Sonia; Carreño Sánchez, Fernando; Antón Revilla, Miguel Ángel; Gort, Elske M.
We study the green upconversion luminescence of Er3+ ions in an aluminosilicate optical fiber upon near infrared excitation at 787 nm. The dependence of the upconversion luminescence on temperature has been determined. As temperature drops from room to cryogenic temperatures, the upconversion green emission reaches a maximum around 40 K, and then decreases. A nearly quadratic dependence of the upconversion luminescence with excitation power is found, which is consistent with a sequential stepwise two-photon absorption process. These results have been explained with a semiclassical model that considers the inhomogeneous broadening of the optical transitions due to glass imperfections, and the dependence of the homogeneous linewidth broadening on temperature.
Plasmon-enhanced terahertz emission in self-assembled quantum dots by femtosecond pulses
(Journal of Applied Physics, 2014) Carreño Sánchez, Fernando; Antón Revilla, Miguel Ángel; Melle Hernández, Sonia; Gómez Calderón, Óscar; Cabrera Granado, Eduardo; Cox, Joel; Singh, Mahi R.; Egatz-Gómez, Ana
A scheme for terahertz (THz) generation from intraband transition in a self-assembled quantum dot (QD) molecule coupled to a metallic nanoparticle (MNP) is analyzed. The QD structure is described as a three-level atom-like system using the density matrix formalism. The MNP with spherical geometry is considered in the quasistatic approximation. A femtosecond laser pulse creates a coherent superposition of two subbands in the quantum dots and produces localized surface plasmons in the nanoparticle which act back upon the QD molecule via dipole-dipole interaction. As a result, coherent THz radiation with a frequency corresponding to the interlevel spacing can be obtained, which is strongly modified by the presence of the MNP. The peak value of the terahertz signal is analyzed as a function of nanoparticle's size, the MNP to QD distance, and the area of the applied laser field. In addition, we theoretically demonstrate that the terahertz pulse generation can be effectively controlled by making use of a train of femtosecond laser pulses. We show that by a proper choice of the parameters characterizing the pulse train a huge enhancement of the terahertz signal is obtained.
Radiation emission from an asymmetric quantum dot coupled to a plasmonic nanostructure
(Journal of Optics, 2016) Antón Revilla, Miguel Ángel; Carreño Sánchez, Fernando; Gómez Calderón, Óscar; Melle Hernández, Sonia; Cabrera Granado, Eduardo
We propose a scheme for controlling the absorption and RFS of a quantum dot (QD) with broken inversion symmetry interacting with a plasmonic nanostructure. The QD is described as a two-level atom-like system with a permanent dipole moment in the excited state. A linearly polarized laser field drives the optical transition of the QD and produces localized surface plasmons in the MNP. The influence of plasmonic effects between the nanoparticle and the dot is analyzed using the Green tensor method. We found terahertz (THz) emission in the resonance fluorescence spectrum when the laser frequency lies above the transition frequency. The position and strength of the THz peaks is controlled by means of the dot-nanoparticle separation. The quantum nature of the emitted THz photons is analyzed by evaluating the second-order fluorescence intensity correlation function. We found a periodic alternation of photon bunching and anti-bunching with a period that depends on the polarization of the driving field.
Phase shift of amplitude-modulated optical signals in graphene oxide water dispersions due to thermal lens focal length oscillation
(Journal of the Optical Society of America B, 2014) Melle Hernández, Sonia; Gómez Calderón, Óscar; Egatz-Gómez, Ana; Cabrera Granado, Eduardo; Carreño Sánchez, Fernando; Salavagione, H. J.; Antón Revilla, Miguel Ángel
We analyze the phase shift induced in an amplitude-modulated laser beam propagating through a water dispersion of graphene oxide sheets in a fiber-to-fiber U-bench. This phase shift arises from the thermally induced nonlinear refraction in the sample. The system exhibits strong optical limiting performance for weak continuous-wave signals. A theoretical model including beam propagation and thermal lens focal length oscillation reproduces the experimental findings.
Project number: 200
Desarrollo de herramientas interactivas con acceso remoto para el aprendizaje de óptica biomédica
(2015) Cabrera Granado, Eduardo; Gómez Calderón, Óscar; Melle Hernández, Sonia; Antón Revilla, Miguel Ángel; Carreño Sánchez, Fernando; Díaz García, Elena; López Alonso, José Manuel; Arrieta Yañez, Francisco
Nuevos documentos de trabajo y consulta basados en IPython Notebook han sido desarrollados con el fin de ofrecer nuevas herramientas para el aprendizaje de la asignatura de Óptica Biomédica de la Facultad de Óptica y Optometría. Este tipo de documentos permiten una mayor libertad al estudiante para explorar distintos temas de Óptica Biomédica facilitando su acceso remoto sin la necesidad de instalar software en su ordenador personal.
Project number: 97
Generación de materiales y recursos para la implantación del Plan de Lenguas para la Internacionalización PLI en la Facultad de Óptica y Optometría
(2016) Sánchez Pérez, María Isabel; Alda Serrano, Javier; Carreño Sánchez, Fernando; Cabrero Granado, Eduardo; Peces Peña, María Dolores; Garrido Mercado, Rafaela; Puell Marín, María Cinta; Martín Pérez, Yolanda; López Alonso, José Manuel; Gómez Calderón, Óscar; Melle Hernández, Sonia; Movilla Serrano, Jesús María
Optical pumping of a single hole spin in a p-doped quantum dot coupled to a metallic nanoparticle
(Physical review B, 2013) Antón Revilla, Miguel Ángel; Carreño Sánchez, Fernando; Melle Hernández, Sonia; Gómez Calderón, Óscar; Cabrera Granado, Eduardo; Singh, Mahi R.
The preparation of quantum states with a defined spin is analyzed in a hybrid system consisting of a p-doped semiconductor quantum dot (QD) coupled to a metallic nanoparticle. The quantum dot is described as a four-level atom-like system using the density matrix formalism. The lower levels are Zeeman-split hole spin states and the upper levels correspond to positively charged excitons containing a spin-up, spin-down hole pair and a spin electron. A metallic nanoparticle with spheroidal geometry is placed in close proximity to the quantum dot, and its effects are considered in the quasistatic approximation. A linearly polarized laser field drives two of the optical transitions of the QD and produces localized surface plasmons in the nanoparticle which act back upon the QD. The frequencies of these localized plasmons are very different along the two principal axes of the nanoparticle, thus producing an anisotropic modification of the spontaneous emission rates of the allowed optical transitions which is accompanied by local-field corrections. This effect translates into a preferential acceleration of some of the optical pathways and therefore into a fast initialization of the QD by excitation with a short optical pulse. The population transfer between the lower levels of the QD and the fidelity is analyzed as a function of the nanoparticle's aspect ratio, the external magnetic field, and the Rabi frequency of the driving field. It is also shown that the main effect of the local-field corrections is a lengthening of the time elapsed to reach the steady-state. The hole spin is predicted to be successfully cooled from 5 to 0.04 K at a magnetic field of 4.6 T applied in the Voigt geometry.
Spectral hole burning in erbium-doped fibers for slow light
(Journal of the Optical Society of America B, 2012) Melle Hernández, Sonia; Gómez Calderón, Óscar; Antón Revilla, Miguel Ángel; Carreño Sánchez, Fernando; Egatz-Gómez, Ana
The homogeneous linewidth of the transition I15/24−I13/24 in highly doped erbium fibers and its dependence with temperature in the range from 10 to 50 K are experimentally characterized using spectral hole burning. The homogeneous linewidth dependence with temperature is quadratic above 20 K where homogeneous broadening is dominated by two-phonon Raman processes, and linear at lower temperatures where direct phonon processes occur. This characteristic power-law dependence was also derived from transmittance measurements. The solution of nonlinear field equations using the results obtained from our experiments predicts that Gaussian probe pulses propagate at subluminal speed through the narrow spectral holes burned in erbium-doped fibers. For gigahertz pulses in the telecommunication window, a fractional delay as high as 0.6 is predicted.