Publications de Yu-Chi Chang | EPFL Graph Search

Droplet-based Liquid-Liquid Extraction and On-Chip IR-Waveguide-Spectroscopy Detection of Cocaine in Human Saliva

Nico de Rooij, Hans Peter Herzig, Peter Van der Wal, Lubos Hvozdara, Philip Wägli, Yu-Chi Chang

We present a portable microsystem to quantitatively detect cocaine in human saliva. The chip combines a simple microfluidic method for multiphase liquid-liquid extraction to transfer cocaine from IR-light absorbing saliva to an IRtransparent solvent with t ...

2012

Design, Fabrication and Characterization of Mid-Infrared Strip Waveguide for Laser Spectroscopy in Liquid Environments

Yu-Chi Chang

Optical sensors based on the interaction between molecular vibrations and mid infrared radiations attracted high attentions in the last decades. In this study, we present the development of a waveguide evanescent field sensor based on the absorption spectr ...

EPFL2012

Demonstration of superprism effect in silicon pillar 2-D photonic crystal infiltrated with liquid crystals

Hans Peter Herzig, Vincent Paeder, Pierre-Yves Baroni, Yu-Chi Chang

Superprism-based deflection of an optical beam is observed in a photonic crystal composed of a triangular lattice of pillars infiltrated with a liquid crystal. The device is based on a Silicon-on-insulator substrate and operates in the telecommunications b ...

2011

Single Mode Mid-infrared Waveguide for Evanescent Sensor Scheme in Liquids

Hans Peter Herzig, Vincent Paeder, Lubos Hvozdara, Philip Wägli, Yu-Chi Chang

A Si/Ge based, single mode, mid-infrared optical waveguide, is used as an evanescent sensor in liquid matrix. The selectivity is achieved by the use of quantum cascade lasers (QCLs) tuned to the maximum absorption of a given analyte. The cocaine detection ...

2011