Advanced photonic devices for microfluidic systems: random lasers

Abstract

A Lab-on-a-chip is an integrated device used for complete in-situ analysis of chemical reactions, as, for example, detection of infectious diseases, that can be used remotely or at the point-of-care. The production of these labs is the core of the FAPESP thematic project on microfluidics, which is a truly multidisciplinary project at the Center for Lasers and Applications at IPEN/SP. In these pocket laboratories, chemical reaction analysis is done through on-board light sources and powerful sensors with very high sensitivity.In the first phase of the thematic project we succeeded in writing waveguides in doped glasses using femtosecond lasers and we reached laser amplification in these glasses. This technology, while partly functional, is not practical and overpriced for disposable devices that could be used in remote locations and at the point of care. For this reason, we anticipate in this project, which corresponds to the second phase of the thematic project, the use of directional (see reference 11) and highly efficient (50%, ref 14) random lasers in microfluidic channels as well as the use of advanced photonic sensors based on new phenomena of light emission. These random lasers, which do not need optics, will have low operating threshold (ref. 15) and high efficiency. The signal increase of the detectors will be obtained by increasing the light-matter interaction during the localization regime (ref 4) through, for example, a Raman process with a signal increase of 20-50 times. The final product will be miniaturized devices that will allow portable laboratory tests to be carried out on time and at remote sites, as intended mainly in the case of infectious diseases and point of care. (AU)