  The possibility of constructing a surface exciton polariton (SEP) based
sensor at room temperature is explored. The proposed SEP sensor is based on the
Kretschmann-Raether configuration of conventional surface plasmon resonance
(SPR) sensor, where the metal thin film was replaced by the J-aggregate cyanine
dye film. The excitation of SEP results in a strong electric field at the
interface of TDBC and analyte, and exponentially decaying into the analyte,
which is sensitive to the refractive index variations of analyte. The
sensitivity of 118.1818 $^\circ/\text{RIU}$ (140.4286 $^\circ/\text{RIU}$) was
achieved for the proposed SEP sensor within the refractive index range
1.0-1.001 (1.33-1.36) of gaseous analyte (aqueous solutions), which is about 2
(3.5) times higher than that of conventional gold-based SPR sensor. The
significant superiority of the SEP sensor in sensitivity revealing SEP as a new
promising mechanism for sensing applications.
