RESUMO
We investigate reversible deformations of polymeric microstructures fabricated using direct laser writing three-dimensional lithography upon immersion in various solvents. Swelling and shrinkage of sub-micrometre size features are induced by interaction with surrounding solvent and such deformations can be exploited to create larger structures whose size, shape, and other structural parameters depend on the surroundings. We describe diffractive optical elements, micro-mechanical sensors and also hybrid deformable structures, that can be used to implement micro-actuation, micro-sensing, and other functionalities highly sought for micro-optical, micro-mechanical, and micro-fluidic systems.
RESUMO
This work reports fabrication of inverse silica opal photonic crystal structures from direct polystyrene micro sphere opals using low-temperature sol-gel infiltration of silica, and examines performance of these photonic crystals as environmental refractive index sensors. Sensitivity of the spectral position and optical attenuation of photonic stop gaps is found to allow detection of the index changes by the amount of ~10(-3). The high value of sensitivity, which is comparable with those of other optical sensing techniques, along with simplicity of the optical detection setup required for sensing, and the low-temperature, energy-efficient fabrication process make inverse silica opals attractive systems for optical sensing applications.
RESUMO
We find strong influence of final-state stimulation on the time-resolved light emission dynamics from semiconductor microcavities after pulsed excitation allowing angle-resonant polariton-polariton scattering on the lower-polariton branch. The polariton dynamics can be controlled by injection of final-state polaritons at densities below a polariton saturation density of 5x10(8) cm(-2). A bosonic enhancement factor in the dynamics of up to 700 is evaluated.