Tamm State-CoupledEmission: Effect of Probe Location and Emission Wavelength

摘要

We report the effect of the probe location and wavelength on the emission spatial distribution and spectral properties of fluorophores located on structures which display Tamm states. Our structure consists of a one-dimensional photonic crystal (1DPC)—that is, a multilayer structure of alternate high and low refractive index dielectrics—and a thin top silver film. Simulations show the presence of Tamm and surface plasmon modes in the structure. The electric field intensities for the Tamm modes are located mostly in the dielectric layer below the metal film. The corresponding field intensities for the surface plamon modes are located above the metal film in the distal side. Tamm states can be in resonance with the incident light normal or near normal to the surface, within the light line, and can be accessed without the use of a coupling prism or gratings. We investigated the emission spectra and angular distribution of the emission for probes located above and below the metal film to explore the interaction of fluorophores with Tamm plasmons and surface plasmons modes. Threeprobes were chosen with different overlap of the emission spectrawith the Tamm modes. The fluorophores below the metal film coupledpredominantly with the Tamm state and displayed more intense and onlyTamm state-coupled emission (TSCE). Probes above the metal film displayboth surface plasmon-coupled emission (SPCE) and Tamm state-coupledemission. In contrast to SPCE, which shows only KR, P-polarized emission,the Tamm states can display both S- and P-polarized emission and canbe populated using both RK and KR illuminations. The TSCE angle ishighly sensitive to wavelength, which suggests the use of Tamm structuresto provide both directional emission and wavelength dispersion. Thecombination of plasmonic and photonic structures with directionalemission close to surface normal offers the opportunities for newdesign formats for clinical testing, portable devices, and other fluorescence-basedapplications.