Study on the fluorescence enhancement characteristics of double-layer dislocated metal gratings

Abstract

In this paper, a double-layer dislocated metal grating hybrid structure is proposed, which is composed of a dislocated metal grating and an inclined dielectric grating. By locating the fluorescent material in the polymethyl methacrylate (PMMA) region of the hybrid structure, the structure achieves a remarkable far-field fluorescence directional emission enhancement. The effects of polarization state, metal grating period, and other parameters on directional fluorescence emission enhancement are studied by the finite-difference time-domain method. After optimizing the parameters, the fluorescence enhancement factor is as high as 1560-fold, of which the emission enhancement is 39-fold and the excitation enhancement is 40-fold. The far-field radiation angle is less than 18°, and the far-field radiation characteristics are improved. This work has application potential in fluorescence detection, imaging, and other luminescence devices.