Spinning nanorods - active optical manipulation of semiconductor nanorods using polarised light

In this Letter we show how a single beam optical trap offers the means for three-dimensional manipulation of semiconductor nanorods in solution. Furthermore rotation of the direction of the electric field provides control over the orientation of the nanorods, which is shown by polarisation analysis of two photon induced fluorescence. Statistics over tens of trapped agglomerates reveal a correlation between the measured degree of polarisation, the trap stiffness and the intensity of the emitted light, confirming that we are approaching the single particle limit.Comment: 7 pages, 4 figure

Terahertz lasing from intersubband polariton-polariton scattering in asymmetric quantum wells

Electric dipole transitions between different cavity polariton branches or between dressed atomic states with the same excitation number are strictly forbidden in centro-symmetric systems. For doped quantum wells in semiconductor microcavities, the strong coupling between an intersubband transition in the conduction band and a cavity mode produces two branches of intersubband cavity polaritons, whose normal-mode energy splitting is tunable and can be in the terahertz region. Here, we show that, by using asymmetric quantum wells, it is possible to have allowed dipolar transitions between different polaritonic branches, leading to the emission of terahertz photons. We present a quantum field theory for such a system and predict that high-efficiency, widely tunable terahertz lasing can be obtained

Fatal infection with Taenia martis metacestodes in a ring-tailed lemur (Lemur catta) living in an Italian zoological garden

A case of fatal infection caused by larval forms of Taenia martis in a ring-tailed lemur (Lemur catta) living in the Rome zoological garden is described. The animal, living in a semi-natural pen with other 15 conspecific individuals and being fed with fresh fruit and vegetables, yoghurt and eggs, was transported to the Istituto Zooprofilattico of Rome for post-mortem examination. The anamnesis included, ten days before the death, apathy, lack of appetite, abdominal distension and diarrhoea. A severe exudative fibrinous-purulent peritonitis with numerous adhesions between the abdominal wall and the bowel loops was detected. After intestine removal, two free and viable, 4cm long, whitish, leaf-like parasitic forms were pinpointed. Macroscopic examination of the two parasites allowed their identification as larval stages of cestodes, identified via molecular analysis as T. martis metacestodes. This report represents the first record of T. martis infection in the host species and in a zoological garden and for the pathological relevance of the infection