We have developed an instrument for real time continuous interferometric measurement of dimensional change in stimuli-responsive hydrogel sensors. The instrument consists of a superfluorecent LED and a low-cost grating spectrometer. All signal conditioning and processing is performed using a microprocessor. We have tested the instrument with a glucose sensitive hydrogel sensor. The rms noise on the length measurement is less than 1.4 nm, whereas rms noise on the length change is less than 0.25 nm. An observed bias of the length measurement can be reduced by minor changes in the frequency estimation algorithm used.

Date Published: 9 March 2015
PDF: 6 pages
Proc. SPIE 9332, Optical Diagnostics and Sensing XV: Toward Point-of-Care Diagnostics, 93320A (9 March 2015); doi: 10.1117/12.2080209

Published in SPIE Proceedings Vol. 9332:
Optical Diagnostics and Sensing XV: Toward Point-of-Care Diagnostics
Gerard L. Coté, Editor(s)