Deep ultraviolet tip-enhanced fluorescence

Abstract

Theoretical calculations were performed for the deep ultraviolet (DUV) tip-enhanced fluorescence (TEF) using Al@Al2O3 core-shell tips. Fluorescence enhancement, spatial resolution and surface plasmon coupled emission (SPCE) of DUV-TEF were quantitatively studied by finite-difference time-domain (FDTD) method. FDTD results demonstrate that the enhancement factor (EF) of TEF can be as high as 3 orders of magnitudes in the optimal TEF geometry. At the DUV excitation wavelength of 244 nm, the spatial resolution and SPCE angles are 6 nm and ±23°, respectively, showing maximum EF of 7.4 ×102. Our results not only help understanding the underlying physical mechanism for developing high-sensitivity and high-resolution DUV-TEF platform, but also contribute to expanding TEF technology from visible to UV range.