Chemical Sensing with Dynamical Nonlinear Information
Satoshi Nakata, Suguru Izuhara, Kenta Masui and Mohammed R. Islam
Using different chemical-sensing systems we show that by observation of time-dependent nonlinear responses one can improve the sensor selectivity with respect to target samples. We discuss the nonlinear perturbation and the related response in two cases: 1: A periodic change in temperature was applied to a SnO2 semiconductor gas sensor. The resulting sensor response was analyzed by fast Fourier transformation and the higher harmonics are a source of abundant information for molecular recognition. 2: The measurements of synchronization in a Wien bridge circuit connected to the electrode system or the semiconductor gas sensor coupled with an external sinusoidal operational force. In this case, sensing is based on the shape of return maps.
Keywords: Nonlinear, chemical sensor, synchronization.