High sensitive chiral molecule detector based on the amplified lateral shift in Kretschmann configuration involving chiral TDBCs*

Abstract

We investigate a high sensitive chiral molecule detector based on Goos–Hanchen shift (S) in Kretschmann configuration involving chiral tri (diethylene glycol monobutyl) citrates (TDBCs). Fresnel equations and the stationary phase method are employed to calculate S. Due to the interaction between surface plasmon polaritons and chiral TDBCs, S with chiral TDBCs are amplified at near the resonant wavelengths of chiral TDBCs. Our calculation results show that although the difference between the resonant wavelengths of left and right TDBCs is 4.5 nm, the positions of the largest S for the structures with left TDBCs and right TDBCs do not overlap. S reaches 400 times (or 200 times) the incident wavelength around the resonant wavelength of left TDBCs (or right TDBCs). The difference of S with chiral TDBCs (Δ S) can reach 400 times or 200 times the incident wavelength in certain conditions, which can be directly observed in experiments. Left TDBCs and right TDBCs are easily distinguished. There is an optimal thickness of the metal film to realize the largest difference of S between Kretschmann configurations with left TDBCs and right TDBCs. Furthermore, we discuss the oscillator strength f, which is mainly determined by TDBC concentration. We find that our proposed detector is quite sensitive with f. By changing f from 0.008 to 0.014 with the step of 0.002, the change of Δ S is no less than five times the incident wavelength (2.9 μm). Our proposed structure is very sensitive to the chirality and the concentration of TDBCs and has potential applications in distinguishing the chirality detector.