Pedro S. Guimarães

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The use of remote labs in undergraduate courses has been reported in literature several times since the mid 90’s. Nevertheless, very few articles present results about the correspondent learning gains obtained by students, and in what conditions those systems can be more efficient, thus suggesting a lack of data concerning their pedagogical effectiveness.(More)
The relative intensity of photonic modes in microcavity pillars with embedded self-assembled quantum dots is shown to be a sensitive function of quantum dot dipole orientation and position. This is deduced from a comparison of experiment and calculated intensities of light emission for many nominally identical pillars. We are able to obtain the overall(More)
We study the reflectivity spectra of photonic crystal slab cavities using an extension of the scattering matrix method that allows treating finite sizes of the spot of the excitation beam. The details of the implementation of the method are presented and then we show that Fano resonances arise as a consequence of the electromagnetic interference between the(More)
In order to provide a more flexible learning environment in physics, the developed projectile launch apparatus enables students to determine the acceleration of gravity and the dependence of a set of parameters in the projectile movement. This apparatus is remotely operated and accessed via web, by first scheduling an access time slot. This machine has a(More)
We show that the combined effect of photon emission and Coulomb interactions may drive an exciton-polariton system towards a dynamical coherent state, even without phonon thermalization or any other relaxation mechanism. Exact diagonalization results for a finite system (a multilevel quantum dot interacting with the lowest-energy photon mode of a(More)
The photoluminescence (PL) properties of thin films of the conjugated polymer [poly(2,5-bis(2(')-ethyl-hexyl)-1,4-phenylenevinylene] have been investigated. At low temperatures the PL spectra show a narrow peak for the electronic transition and a series of well defined vibronic sidebands, which clearly reveal the electron coupling with two different(More)
We investigate the effects of the excitation power on the photoluminescence spectra of aqueous CdTe/CdS core-shell quantum dots. We have focused our efforts on nanoparticles that are drop-cast on a silicon nitride substrate and dried out. Under such conditions, the emission intensity of these nanocrystals decreases exponentially and the emission center(More)
The temperature dependence of the photoluminescence properties of a thin film of poly[2-methoxy-5-(2(')-ethylhexyloxy)-p-phenylene-vinylene], MEH-PPV, fabricated by spin coating, is analyzed. The evolution with temperature of the peak energy of the purely electronic transition, of the first vibronic band, of the effective conjugation length, and of the(More)
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