Band engineering stands as an efficient route to induce strongly correlated quantum many-body phenomena. Besides inspiring analogies among diverse physical fields, tuning on demand the group velocity is highly attractive in photonics because it allows unconventional flows of light. Λ-schemes offer a route to control the propagation of light in a lattice-free configurations, enabling exotic phases such as slow-light and allowing for highly optical non-linear systems.
View Article and Find Full Text PDFThe transmission properties of a photonic crystal immersed in several different oils have been characterized using terahertz time domain spectroscopy in the spectral range of 0.3-1.5 THz.
View Article and Find Full Text PDFIn this article, we show an alternative low-cost fabrication method to obtain poly(dimethyl siloxane) (PDMS) microfluidic devices. The proposed method allows the inscription of micron resolution channels on polystyrene (PS) surfaces, used as a mold for the wanted microchip's production, by applying a high absorption coating film on the PS surface to ablate it with a focused low-power visible laser. The method allows for obtaining micro-resolution channels at powers between 2 and 10 mW and can realize any two-dimensional polymeric devices.
View Article and Find Full Text PDFA method to design Ronchi-Hartmann screens for improved alignment in the testing of fast plano-convex spherical lenses is presented. We design null screens that produce aligned straight fringes for observed patterns. The designs of these null screens are based on knowledge of the caustic by refraction.
View Article and Find Full Text PDFA positioning system with approximately nanometer resolution has been developed based on a new implementation of a motor-driven screw scheme. In contrast to conventional positioning systems based on piezoelectric elements, this system shows remarkably low levels of drift and vibration, and eliminates the need for position feedback during typical data acquisition processes. During positioning or scanning processes, non-repeatability and hysteresis problems inherent in mechanical positioning systems are greatly reduced using a software feedback scheme.
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