Educação matemática pela arte
Gusmão, Lucimar Donizete
2013-08-28
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5 records were found.
Scanning near-field optical microscopy (SNOM) has been applied to investigate the dispersion and nonlinear phenomena in a multimode Ta2O5 rectangular waveguide. Unlike the conventional approach of observing only the output spectra, the SNOM technique can collect the localised spectra from the evanescent field at various locations of the waveguide. This provides the visualisation of pulse evolution prior to the final development as the output light. The SNOM-acquired spectra consist of unique features which have not been observed before in previous nonlinear pulse propagation researches. These distinctive characteristics are attributed to the localised nature of the data and the multimode nonlinear pulse propagation. In order to understand the underlying physics of the experimental data, a numerical model simulating this SNOM visualisat...
We describe the first non-destructive measurements of the evolution of the optical continuum along a non-linear waveguide. By utilizing near-field microscopy, the spectral variation can be imaged along and across the waveguide with sub-wavelength resolution.
Measurement of spectral interference with a near-field scanning optical microscope is used to determine directly the variation of group velocity between modes of a planar slab waveguide as the modes propagate along the guide.
Near-field scanning optical microscopy provides a tool for studying the behavior of optical fields inside waveguides. In this experiment the authors measure directly the variation of group velocity between different modes of a planar slab waveguide as the modes propagate along the guide. The measurement is made using the spectral interference between pulses propagating inside the waveguide with different group velocities, collected using a near-field scanning optical microscope at different points down the guide and spectrally resolved. The results are compared to models of group velocities in simple guides.
We describe what is to our knowledge the first nondestructive measurement of the evolution of an optical continuum as a function of distance along a nonlinear waveguide. Spectral mapping is achieved on a subwavelength scale by utilizing near-field microscopy to probe the waveguide's evanescent field. The measured continuum broadening along the waveguide agrees in general form with predictions of broadening from theoretical calculations, but differs in some important details. Subwavelength resolution measurements are made both along and across the waveguide to reveal spectral variations not seen before by other techniques.
