We present a new integrated optical sensor for absorption spectroscopy in a hostile environment, based on a nanochannel waveguide structure in glass. The nanochannel waveguide is made by bonding two ion-exchanged borosilicate glass wafers, one of them being etched by reactive ion etching to create a 100 nm deep fluidic channel. Typical fluid/light interaction factors of 2.3 % can be achieved inside a 7.4 pL volume of fluid, over a 550 nm bandwidth, surmounting evanescent wave sensors in terms of confinement efficiency and allowing spectrometric measurements. Absorption measurements have been performed on hexahydrate neodymium nitrate in nitric acid solutions of various concentrations leading to a minimum detectable absorption coefficient of 0.57 cm^-1, which can be further decreased by implementing low bending-loss spiral-like nanochannel waveguides.

Date Published: 6 March 2013
PDF: 12 pages
Proc. SPIE 8627, Integrated Optics: Devices, Materials, and Technologies XVII, 86270L (6 March 2013); doi: 10.1117/12.2002431

Published in SPIE Proceedings Vol. 8627:
Integrated Optics: Devices, Materials, and Technologies XVII
Jean Emmanuel Broquin; Gualtiero Nunzi Conti, Editor(s)