Browsing CAP - Indexed Articles in Conferences by Author "Ana Rita Ribeiro"
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ItemCAPTURA DE CÉLULAS COM LUZ( 2012) Ariel Guerreiro ; Ana Rita Ribeiro ; Pedro Jorge
ItemComputational modeling of red blood cells trapping using Optical Fiber Tweezers( 2017) Joana Isabel Paiva ; Ana Rita Ribeiro ; Pedro Jorge ; Carla Carmelo Rosa ; João Paulo CunhaOptical Tweezers (OT) are able to trap/manipulate dielectric particles with few microns in a contactless manner due to forces exerted on them by a strongly focused optical beam. OT are being applied in Biology/Medicine, especially Optical Fiber Tweezers (OFT), for being simpler and more flexible than the conventional setups. Despite of the trapping phenomena of symmetrical particles by OFTs being already modeled, effects regarding complex bodies remain poorly understood. Here we provide a 2D characterization of the trapping forces exerted by a laser OFT on a geometric form of a Red Blood Cell (RBC), occupying different positions in a grid, using the method proposed by Barnett&Loudon. Comparisons were made between the forces exerted on a RBC having the mean normal size; a RBC with 80% of the normal size and an 1.5µm circular particle, due to the size and shape variability of biological-derived structures. The influence of RBCs inclination angles regarding its major axis on trapping performance was also evaluated for angles of p/4 and p/2. Simulation results showed that trapping phenomena are possible for all the conditions evaluated, as well as calculated trapping forces range was according with the literature (pN). We observed that, despite of modeled particles having the same optical characteristics, features such as particle geometry, size, position and inclination degree influence trapping. Trapping forces magnitude was higher for RBC relatively to the circular symmetrical particle; for large RBCs than RBCs with smaller dimensions; and for inclined RBCs than erythrocytes horizontally aligned. Those results reinforce the importance of modeling optical experiments to determine relevant parameters which affect trapping performance. © 2017 IEEE.
ItemFiber Optical Beam Shaping Using Polymeric Structures( 2014) Ana Rita Ribeiro ; Queiros,RB ; Ariel Guerreiro ; Ecoffet,C ; Soppera,O ; Pedro JorgeA method to control the output intensity profile of optical fibers is presented. Using guided wave photo-polymerization in multimode structures the fabrication with modal assisted shaping of polymeric micro lenses is demonstrated. Results showing that a given linear polarized mode can be selectively excited controlling the intensity distribution at the fiber tip are presented. This pattern is then reproduced in the polymeric micro structure fabricated at the fiber tip thus modulating its output intensity distribution. Such structures can therefore be used to obtain at the fiber tip predetermined intensity patterns for attaining optical trapping or patterned illumination.
ItemMicrofluidic chip for spectroscopic and refractometric analysis( 2012) Hugo Aguas ; Ana Rita Ribeiro ; Iracema Martinho ; Iwona Bernacka ; DAvid Barata ; Pedro Jorge ; Abel Oliva