One of many possible applications of a one-dimensional photonic crystal (1DPhC) is sensing utilizing the Bloch surface wave (BSW). In this paper, we present a method of relative humidity (RH) sensing based on the phase shift of the BSW supported by a truncated 1DPhC represented by a multilayered structure. The structure is composed of six TiO2/SiO2 bilayers with a termination layer of TiO2. The BSW is excited by a total internal reflection of light in the Kretschmann configuration. A spectral interferometric technique is used to obtain a channeled spectrum due to projections of both reflected s and p polarized light waves. The phase is retrieved using a Windowed Fourier transform and spectral derivatives forming peaks are calculated. The sensing concept is based on tracking the derivative peak as a function of RH. A sensitivity to humidity of 0.028 nm/%RH and figure of merit of 0.0042 %RH−1 were determined.
A theoretical study of a new sensing concept based on Bloch surface waves (BSWs), which utilizes a onedimensional photonic crystal (1DPhC) represented by a multilayer structure, is presented. 1DPhCs have a number of useful features, including physical and chemical robustness. We model the response of a BK7 prism/multilayer/analyte system in the Kretschmann configuration for s- and p-polarized waves. We show that the 1DPhC supports surface electromagnetic waves at frequencies within the forbidden transmission band of the multilayer structure. A dip in the reflectance spectrum for s-polarized wave represents the excitation of the BSW and this is demonstrated for air and gaseous analytes.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.